Abstraction Health

Glycine — Expert Claims

Extracted from publicly available podcast transcripts and videos. Each claim is attributed and sourced.

Expert Consensus

Universal consensusResearch agrees
3/5
Experts mention
3
Recommend
1
Flag caution
Rhonda Patrick
Rhonda Patrick Recommends Caution
Research agrees104 claims9grams or 3gramsdissolved in water
Andrew Huberman
Andrew Huberman Recommends
Partially supported66 claims3gramsdissolved in water
Mark Hyman
Mark Hyman Recommends
Research agrees6 claims500milligramscapsule

Dose divergence: Experts recommend different amounts (9grams, 3grams, 500milligrams). Check the Stack & Timing tab for study-backed dosing ranges.

Claims are extracted using AI (Claude) from publicly available transcripts, each attributed to its source with an extraction-confidence rating (high / medium / low) so it can be verified, then compared against PubMed research. See how our data is made.

Experts in this data:Rhonda PatrickAndrew HubermanMark Hyman

176 expert mentions

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Direct recommendation

Bone broth and collagen peptide supplements are glycine-rich foods, but supplemental glycine at 3 to 10 grams per day is an alternative.

Extracted claim

Supplemental glycine at 3 to 10 grams per day is an alternative to bone broth and collagen peptide supplements for supporting collagen synthesis.

Insufficient evidence to assessHigh confidence

The provided research corpus does not contain studies that directly evaluate supplemental glycine as an alternative to bone broth or collagen peptides for collagen synthesis support. While PMID 378513…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Direct recommendation

Bone broth and collagen peptide supplements are glycine-rich foods, but supplemental glycine at 3 to 10 grams per day is an alternative.

Extracted claim

Supplemental glycine at 3 to 10 grams per day is an alternative to bone broth and collagen peptide supplements for supporting collagen synthesis.

Insufficient evidence to assessHigh confidence

None of the provided studies directly evaluate supplemental glycine (3–10 g/day) as an alternative to bone broth or collagen peptide supplements for collagen synthesis support. PMID 37851316, a system…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Direct recommendation

The dose that I take and that was used in that study is 3 grams about 30 minutes before bed. Glycine is cheap, has essentially no side effects at this dose, and it tastes slightly sweet, which makes it easy to dissolve in water and drink.

Extracted claim

Huberman recommends 3 grams of glycine taken about 30 minutes before bed for sleep, noting it is cheap, has essentially no side effects at this dose, and can be dissolved in water due to its slightly sweet taste.

3 gramsdissolved in water30 minutes before bed📍 sleep optimization
Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly investigate glycine supplementation at 3 grams for sleep improvement, sleep onset, or sleep quality outcomes. While PMID 28337245 (a review on glycine's multif…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Direct recommendation

The dose that I take and that was used in that study is 3 grams about 30 minutes before bed. Glycine is cheap, has essentially no side effects at this dose, and it tastes slightly sweet, which makes it easy to dissolve in water and drink.

Extracted claim

Huberman recommends 3 grams of glycine taken about 30 minutes before bed for sleep, noting it is cheap, has essentially no side effects at this dose, and can be dissolved in water due to its slightly sweet taste.

3 gramsdissolved in water30 minutes before bed📍 sleep optimization
Insufficient evidence to assessHigh confidence

The provided research corpus does not contain studies directly examining glycine supplementation for sleep outcomes. The most relevant paper is the systematic review (PMID: 37851316) on glycine admini…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Direct recommendation

The dose studied is 3 grams taken 30 to 60 minutes before sleep.

Extracted claim

The recommended dose of glycine for sleep is 3 grams taken 30 to 60 minutes before sleep.

3 grams30 to 60 minutes before sleep📍 For sleep benefit, based on the studied dose
Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly investigate glycine supplementation for sleep quality, dosing, or timing. The retrieved literature covers unrelated topics such as GlyNAC for aging, glycine as…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Direct recommendation

The dose that I take and that was used in that study is 3 grams about 30 minutes before bed. Glycine is cheap, has essentially no side effects at this dose, and it tastes slightly sweet, which makes it easy to dissolve in water and drink.

Extracted claim

Huberman recommends 3 grams of glycine taken about 30 minutes before bed for sleep, noting it is cheap, has essentially no side effects at this dose, and can be dissolved in water due to its slightly sweet taste.

3 gramsdissolved in water30 minutes before bed📍 sleep optimization
Insufficient evidence to assessHigh confidence

None of the 10 published studies listed directly evaluate glycine supplementation at 3 grams taken before bed for sleep improvement. The GlyNAC RCT (PMID: 35975308) and glycine reviews (PMIDs: 3751099…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Direct recommendation

The dose that I take and that was used in that study is 3 grams about 30 minutes before bed. Glycine is cheap, has essentially no side effects at this dose, and it tastes slightly sweet, which makes it easy to dissolve in water and drink.

Extracted claim

Huberman recommends 3 grams of glycine taken about 30 minutes before bed for sleep, noting it is cheap, has essentially no side effects at this dose, and can be dissolved in water due to its slightly sweet taste.

3 gramsdissolved in water30 minutes before bed📍 sleep optimization
Insufficient evidence to assessHigh confidence

The provided research corpus does not contain studies directly evaluating glycine supplementation for sleep improvement. While PMID 37851316 is a systematic review on glycine administration in human a…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Direct recommendation

The dose studied is 3 grams taken 30 to 60 minutes before sleep.

Extracted claim

The recommended dose of glycine for sleep is 3 grams taken 30 to 60 minutes before sleep.

3 grams30 to 60 minutes before sleep📍 For sleep benefit, based on the studied dose
Insufficient evidence to assessHigh confidence

None of the 10 provided research papers directly address glycine supplementation for sleep, nor do any examine the specific dose (3 grams) or timing (30–60 minutes before sleep) cited in the expert's…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Direct recommendation

The dose studied is 3 grams taken 30 to 60 minutes before sleep.

Extracted claim

The recommended dose of glycine for sleep is 3 grams taken 30 to 60 minutes before sleep.

3 grams30 to 60 minutes before sleep📍 For sleep benefit, based on the studied dose
Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly examine glycine supplementation for sleep quality, dosing protocols, or timing recommendations. The retrieved literature covers tangentially related topics suc…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Direct recommendation

Bone broth and collagen peptide supplements are glycine-rich foods, but supplemental glycine at 3 to 10 grams per day is an alternative.

Extracted claim

Supplemental glycine at 3 to 10 grams per day is an alternative to bone broth and collagen peptide supplements for supporting collagen synthesis.

Insufficient evidence to assessHigh confidence

The available research does not directly address the claim that supplemental glycine at 3–10 grams per day serves as an alternative to bone broth or collagen peptides for collagen synthesis support. P…

Mark Hyman
Mark Hyman
Cleveland Clinic Center for Functional Medicine
Direct recommendation

I can tell you the best way to lower homoy um is 500 milligrams daily in a capsule form of trimethyl glycine TMG lots of great manufacturers that make it out there I make one symbiotica makes it Thorn pure encapsulations it's not an expensive nutrient if you have hyper homo symia that's a that's a must have supplement

Extracted claim

Trimethylglycine (TMG) at 500 mg daily in capsule form is the best way to lower homocysteine, and is a must-have supplement for people with hyperhomocysteinemia.

500 milligramscapsuledaily📍 recommended for lowering homocysteine levels, described as a must-have for those with hyperhomocysteinemia
Insufficient evidence to assessHigh confidence

None of the 20 published research summaries provided address trimethylglycine (TMG) supplementation or its effects on homocysteine levels. While several studies discuss glycine (PMIDs 28337245, 378513…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Direct recommendation

Bone broth and collagen peptide supplements are glycine-rich foods, but supplemental glycine at 3 to 10 grams per day is an alternative.

Extracted claim

Supplemental glycine at 3 to 10 grams per day is an alternative to bone broth and collagen peptide supplements for supporting collagen synthesis.

Partially supportedHigh confidence

The claim that glycine supplementation supports collagen synthesis has biological plausibility supported by the included literature. The glycine review (PMID: 28337245) discusses its multifarious bene…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Direct recommendation

The dose that I take and that was used in that study is 3 grams about 30 minutes before bed. Glycine is cheap, has essentially no side effects at this dose, and it tastes slightly sweet, which makes it easy to dissolve in water and drink.

Extracted claim

Huberman recommends 3 grams of glycine taken about 30 minutes before bed for sleep, noting it is cheap, has essentially no side effects at this dose, and can be dissolved in water due to its slightly sweet taste.

3 gramsdissolved in water30 minutes before bed📍 sleep optimization
Insufficient evidence to assessHigh confidence

The provided research list does not contain studies directly evaluating glycine supplementation for sleep outcomes, dosing, or timing. While PMID 37851316 (a systematic review on glycine administratio…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Direct recommendation

The dose studied is 3 grams taken 30 to 60 minutes before sleep.

Extracted claim

The recommended dose of glycine for sleep is 3 grams taken 30 to 60 minutes before sleep.

3 grams30 to 60 minutes before sleep📍 For sleep benefit, based on the studied dose
Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly examine glycine supplementation for sleep outcomes, dosing protocols, or timing recommendations. The most potentially relevant study (PMID: 37851316) is a syst…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Direct recommendation

Bone broth and collagen peptide supplements are glycine-rich foods, but supplemental glycine at 3 to 10 grams per day is an alternative.

Extracted claim

Supplemental glycine at 3 to 10 grams per day is an alternative to bone broth and collagen peptide supplements for supporting collagen synthesis.

Partially supportedHigh confidence

Several studies in the provided list offer indirect support for the claim. The RCT on GlyNAC supplementation (PMID: 35975308) demonstrates that supplemental glycine has measurable biological effects i…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Direct recommendation

The dose that I take and that was used in that study is 3 grams about 30 minutes before bed. Glycine is cheap, has essentially no side effects at this dose, and it tastes slightly sweet, which makes it easy to dissolve in water and drink.

Extracted claim

Huberman recommends 3 grams of glycine taken about 30 minutes before bed for sleep, noting it is cheap, has essentially no side effects at this dose, and can be dissolved in water due to its slightly sweet taste.

3 gramsdissolved in water30 minutes before bed📍 sleep optimization
Insufficient evidence to assessHigh confidence

None of the 10 studies listed directly investigate glycine supplementation (3g) for sleep improvement. The closest relevant papers are a review on glycine's anti-inflammatory and multifarious benefits…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Direct recommendation

Bone broth and collagen peptide supplements are glycine-rich foods, but supplemental glycine at 3 to 10 grams per day is an alternative.

Extracted claim

Supplemental glycine at 3 to 10 grams per day is an alternative to bone broth and collagen peptide supplements for supporting collagen synthesis.

Insufficient evidence to assessHigh confidence

None of the provided studies directly test supplemental glycine (3–10 g/day) as an alternative to bone broth or collagen peptides for collagen synthesis. The most relevant study (PMID 27852613) examin…

Mark Hyman
Mark Hyman
Cleveland Clinic Center for Functional Medicine
Direct recommendation

I can tell you the best way to lower homoy um is 500 milligrams daily in a capsule form of trimethyl glycine TMG lots of great manufacturers that make it out there I make one symbiotica makes it Thorn pure encapsulations it's not an expensive nutrient if you have hyper homo symia that's a that's a must have supplement

Extracted claim

Trimethylglycine (TMG) at 500 mg daily in capsule form is the best way to lower homocysteine, and is a must-have supplement for people with hyperhomocysteinemia.

500 milligramscapsuledaily📍 recommended for lowering homocysteine levels, described as a must-have for those with hyperhomocysteinemia
Insufficient evidence to assessHigh confidence

None of the 20 published studies provided directly evaluate trimethylglycine (TMG) for lowering homocysteine or treating hyperhomocysteinemia. While some studies touch on related topics — such as the…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Direct recommendation

Bone broth and collagen peptide supplements are glycine-rich foods, but supplemental glycine at 3 to 10 grams per day is an alternative.

Extracted claim

Supplemental glycine at 3 to 10 grams per day is an alternative to bone broth and collagen peptide supplements for supporting collagen synthesis.

Insufficient evidence to assessHigh confidence

None of the provided studies directly test supplemental glycine (3–10 g/day) as a substitute for bone broth or collagen peptides in supporting collagen synthesis. The most relevant study (PMID 2785261…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Direct recommendation

Bone broth and collagen peptide supplements are glycine-rich foods, but supplemental glycine at 3 to 10 grams per day is an alternative.

Extracted claim

Supplemental glycine at 3 to 10 grams per day is an alternative to bone broth and collagen peptide supplements for supporting collagen synthesis.

Partially supportedHigh confidence

The claim that glycine supplementation supports collagen synthesis has biological plausibility supported by the glycine review literature (PMIDs 37510995, 28337245), as glycine is a primary amino acid…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Direct recommendation

The dose studied is 3 grams taken 30 to 60 minutes before sleep.

Extracted claim

The recommended dose of glycine for sleep is 3 grams taken 30 to 60 minutes before sleep.

3 grams30 to 60 minutes before sleep📍 For sleep benefit, based on the studied dose
Insufficient evidence to assessHigh confidence

None of the 10 listed studies specifically examine glycine supplementation for sleep, the 3-gram dose, or the 30-to-60-minute pre-sleep timing window. While two reviews (PMIDs 37510995 and 28337245) d…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Direct recommendation

The dose studied is 3 grams taken 30 to 60 minutes before sleep.

Extracted claim

The recommended dose of glycine for sleep is 3 grams taken 30 to 60 minutes before sleep.

3 grams30 to 60 minutes before sleep📍 For sleep benefit, based on the studied dose
Insufficient evidence to assessHigh confidence

None of the 10 published research studies provided directly investigate glycine supplementation for sleep, nor do they address the specific dosing recommendation of 3 grams taken 30–60 minutes before…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Direct recommendation

The dose studied is 3 grams taken 30 to 60 minutes before sleep.

Extracted claim

The recommended dose of glycine for sleep is 3 grams taken 30 to 60 minutes before sleep.

3 grams30 to 60 minutes before sleep📍 For sleep benefit, based on the studied dose
Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly examine glycine supplementation for sleep outcomes, dosing protocols, or timing recommendations. The most relevant study (PMID: 37851316) is a systematic revie…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Direct recommendation

The dose studied is 3 grams taken 30 to 60 minutes before sleep.

Extracted claim

The recommended dose of glycine for sleep is 3 grams taken 30 to 60 minutes before sleep.

3 grams30 to 60 minutes before sleep📍 For sleep benefit, based on the studied dose
Insufficient evidence to assessHigh confidence

None of the 10 published research sources listed address glycine supplementation for sleep, specific dosing for sleep, or the 30-60 minute pre-sleep timing recommendation. While glycine's anti-inflamm…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Direct recommendation

The dose that I take and that was used in that study is 3 grams about 30 minutes before bed. Glycine is cheap, has essentially no side effects at this dose, and it tastes slightly sweet, which makes it easy to dissolve in water and drink.

Extracted claim

Huberman recommends 3 grams of glycine taken about 30 minutes before bed for sleep, noting it is cheap, has essentially no side effects at this dose, and can be dissolved in water due to its slightly sweet taste.

3 gramsdissolved in water30 minutes before bed📍 sleep optimization
Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly investigate glycine supplementation (3g or any dose) as a sleep aid in humans. While PMID 28337245 is a general review of glycine's benefits and PMID 35975308…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Evidence-backed claim

This was a randomized crossover study that gave 3 grams of glycine before bed to healthy volunteers and measured sleep architecture via polysomnography. The glycine group showed significant increases in slow-wave sleep — stage 3 non-REM sleep — and reductions in next-day fatigue and sleepiness.

Extracted claim

The Bannai et al. 2012 randomized crossover study found that 3 grams of glycine taken before bed significantly increased slow-wave sleep and reduced next-day fatigue and sleepiness in healthy volunteers.

3 gramsbefore bed📍 Given to healthy volunteers in a randomized crossover study
Insufficient evidence to assessHigh confidence

None of the 10 provided research abstracts correspond to the Bannai et al. 2012 randomized crossover study on glycine and sleep that the expert cites. The provided literature covers topics such as Gly…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Evidence-backed claim

Glycine is generally recognized as safe by the FDA, and the therapeutic range in studies is typically 3 to 15 grams. At 3 grams for sleep, you're well within the safe range.

Extracted claim

Glycine is generally recognized as safe by the FDA, and the therapeutic range in studies is typically 3 to 15 grams, with 3 grams for sleep being well within the safe range.

3 grams📍 sleep; noted as well within safe range of 3–15 grams
Partially supportedHigh confidence

The glycine safety claim and dosage range are partially supported by the available literature. The GlyNAC RCT (PMID: 35975308) and multiple reviews on glycine (PMIDs: 37510995, 28337245) confirm glyci…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Evidence-backed claim

There's actually a clinical trial by Kumar et al. showing that supplementing with glycine and N-acetylcysteine in older adults significantly restored glutathione levels and improved several markers of oxidative stress and mitochondrial function.

Extracted claim

A clinical trial by Kumar et al. showed that supplementing with glycine and N-acetylcysteine in older adults significantly restored glutathione levels and improved markers of oxidative stress and mitochondrial function.

Supported by researchHigh confidence

The expert's claim is directly supported by PMID 35975308, which is an RCT examining GlyNAC (glycine and N-acetylcysteine) supplementation in older adults. The study title explicitly references improv…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Evidence-backed claim

The key study I want to point to is by Bannai and Kawai, published in 2012 in the journal Sleep and Biological Rhythms. They gave subjects 3 grams of glycine before bed and saw significant improvements in sleep quality ratings, reductions in fatigue and sleepiness the following day, and objective improvements in polysomnography — specifically increased slow-wave sleep, which is deep non-REM sleep.

Extracted claim

A 2012 study by Bannai and Kawai in Sleep and Biological Rhythms found that 3 grams of glycine before bed significantly improved sleep quality ratings, reduced next-day fatigue and sleepiness, and objectively improved polysomnography results, specifically increasing slow-wave sleep.

3 gramsbefore bed📍 sleep quality improvement in study subjects
Insufficient evidence to assessHigh confidence

The expert specifically references a 2012 study by Bannai and Kawai published in Sleep and Biological Rhythms examining 3g glycine before bed and polysomnography outcomes. None of the 10 retrieved Pub…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Evidence-backed claim

This was a randomized crossover study that gave 3 grams of glycine before bed to healthy volunteers and measured sleep architecture via polysomnography. The glycine group showed significant increases in slow-wave sleep — stage 3 non-REM sleep — and reductions in next-day fatigue and sleepiness.

Extracted claim

The Bannai et al. 2012 randomized crossover study found that 3 grams of glycine taken before bed significantly increased slow-wave sleep and reduced next-day fatigue and sleepiness in healthy volunteers.

3 gramsbefore bed📍 Given to healthy volunteers in a randomized crossover study
Insufficient evidence to assessHigh confidence

The expert specifically cites the Bannai et al. 2012 study on glycine and sleep, but this study does not appear in any of the 10 provided PubMed references. None of the listed studies address glycine'…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Evidence-backed claim

This was a randomized crossover study that gave 3 grams of glycine before bed to healthy volunteers and measured sleep architecture via polysomnography. The glycine group showed significant increases in slow-wave sleep — stage 3 non-REM sleep — and reductions in next-day fatigue and sleepiness.

Extracted claim

The Bannai et al. 2012 randomized crossover study found that 3 grams of glycine taken before bed significantly increased slow-wave sleep and reduced next-day fatigue and sleepiness in healthy volunteers.

3 gramsbefore bed📍 Given to healthy volunteers in a randomized crossover study
Insufficient evidence to assessHigh confidence

The expert specifically cites the Bannai et al. 2012 study on glycine and sleep, but this study is not present in the provided PubMed research list. None of the 10 listed studies address glycine's eff…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Evidence-backed claim

A 2019 paper by Ables and colleagues showed that adding glycine to a high-methionine diet in mice produced similar longevity outcomes to methionine restriction itself.

Extracted claim

A 2019 paper by Ables and colleagues showed that adding glycine to a high-methionine diet in mice produced similar longevity outcomes to methionine restriction itself.

Insufficient evidence to assessHigh confidence

None of the 10 published research entries provided contain the Ables et al. (2019) study that the expert specifically references, nor do any of them address the direct comparison of glycine supplement…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Evidence-backed claim

The key study I want to point to is by Bannai and Kawai, published in 2012 in the journal Sleep and Biological Rhythms. They gave subjects 3 grams of glycine before bed and saw significant improvements in sleep quality ratings, reductions in fatigue and sleepiness the following day, and objective improvements in polysomnography — specifically increased slow-wave sleep, which is deep non-REM sleep.

Extracted claim

A 2012 study by Bannai and Kawai in Sleep and Biological Rhythms found that 3 grams of glycine before bed significantly improved sleep quality ratings, reduced next-day fatigue and sleepiness, and objectively improved polysomnography results, specifically increasing slow-wave sleep.

3 gramsbefore bed📍 sleep quality improvement in study subjects
Insufficient evidence to assessHigh confidence

The expert's claim refers specifically to a 2012 study by Bannai and Kawai published in Sleep and Biological Rhythms examining glycine's effects on sleep quality, fatigue, and polysomnography outcomes…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Evidence-backed claim

Glycine is generally recognized as safe by the FDA, and the therapeutic range in studies is typically 3 to 15 grams. At 3 grams for sleep, you're well within the safe range.

Extracted claim

Glycine is generally recognized as safe by the FDA, and the therapeutic range in studies is typically 3 to 15 grams, with 3 grams for sleep being well within the safe range.

3 grams📍 sleep; noted as well within safe range of 3–15 grams
Partially supportedHigh confidence

The provided literature includes reviews and an RCT referencing glycine supplementation (PMIDs 37510995, 28337245, 35975308), which supports glycine's general safety profile and use in therapeutic con…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Evidence-backed claim

The key study I want to point to is by Bannai and Kawai, published in 2012 in the journal Sleep and Biological Rhythms. They gave subjects 3 grams of glycine before bed and saw significant improvements in sleep quality ratings, reductions in fatigue and sleepiness the following day, and objective improvements in polysomnography — specifically increased slow-wave sleep, which is deep non-REM sleep.

Extracted claim

A 2012 study by Bannai and Kawai in Sleep and Biological Rhythms found that 3 grams of glycine before bed significantly improved sleep quality ratings, reduced next-day fatigue and sleepiness, and objectively improved polysomnography results, specifically increasing slow-wave sleep.

3 gramsbefore bed📍 sleep quality improvement in study subjects
Insufficient evidence to assessHigh confidence

None of the 10 retrieved studies correspond to the Bannai and Kawai (2012) Sleep and Biological Rhythms study cited by Huberman, nor do any of them investigate glycine supplementation for sleep qualit…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Evidence-backed claim

Glycine is generally recognized as safe by the FDA, and the therapeutic range in studies is typically 3 to 15 grams. At 3 grams for sleep, you're well within the safe range.

Extracted claim

Glycine is generally recognized as safe by the FDA, and the therapeutic range in studies is typically 3 to 15 grams, with 3 grams for sleep being well within the safe range.

3 grams📍 sleep; noted as well within safe range of 3–15 grams
Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly examine glycine's FDA GRAS status, its therapeutic dosing range, or its specific effects on sleep at 3 grams. While PMID 28337245 (a narrative review on glycin…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Evidence-backed claim

A 2019 paper by Ables and colleagues showed that adding glycine to a high-methionine diet in mice produced similar longevity outcomes to methionine restriction itself.

Extracted claim

A 2019 paper by Ables and colleagues showed that adding glycine to a high-methionine diet in mice produced similar longevity outcomes to methionine restriction itself.

Insufficient evidence to assessHigh confidence

None of the 10 provided PubMed studies reference the 2019 Ables et al. paper or examine glycine supplementation on a high-methionine diet in the context of longevity outcomes in mice. The claim is a s…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Evidence-backed claim

There's actually a clinical trial by Kumar et al. showing that supplementing with glycine and N-acetylcysteine in older adults significantly restored glutathione levels and improved several markers of oxidative stress and mitochondrial function.

Extracted claim

A clinical trial by Kumar et al. showed that supplementing with glycine and N-acetylcysteine in older adults significantly restored glutathione levels and improved markers of oxidative stress and mitochondrial function.

Insufficient evidence to assessHigh confidence

None of the 10 provided studies reference the Kumar et al. clinical trial cited by Rhonda Patrick, nor do any of them directly investigate glycine and N-acetylcysteine (GlyNAC) supplementation in olde…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Evidence-backed claim

A 2019 paper by Ables and colleagues showed that adding glycine to a high-methionine diet in mice produced similar longevity outcomes to methionine restriction itself.

Extracted claim

A 2019 paper by Ables and colleagues showed that adding glycine to a high-methionine diet in mice produced similar longevity outcomes to methionine restriction itself.

Insufficient evidence to assessHigh confidence

None of the 10 provided studies reference the Ables et al. 2019 paper or investigate glycine supplementation in the context of methionine restriction and longevity outcomes in mice. The retrieved lite…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Evidence-backed claim

This was a randomized crossover study that gave 3 grams of glycine before bed to healthy volunteers and measured sleep architecture via polysomnography. The glycine group showed significant increases in slow-wave sleep — stage 3 non-REM sleep — and reductions in next-day fatigue and sleepiness.

Extracted claim

The Bannai et al. 2012 randomized crossover study found that 3 grams of glycine taken before bed significantly increased slow-wave sleep and reduced next-day fatigue and sleepiness in healthy volunteers.

3 gramsbefore bed📍 Given to healthy volunteers in a randomized crossover study
Insufficient evidence to assessHigh confidence

None of the 10 provided PubMed records correspond to or directly address the Bannai et al. 2012 randomized crossover study on glycine and sleep. While PMID 37851316 is a systematic review on glycine a…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Evidence-backed claim

The key study I want to point to is by Bannai and Kawai, published in 2012 in the journal Sleep and Biological Rhythms. They gave subjects 3 grams of glycine before bed and saw significant improvements in sleep quality ratings, reductions in fatigue and sleepiness the following day, and objective improvements in polysomnography — specifically increased slow-wave sleep, which is deep non-REM sleep.

Extracted claim

A 2012 study by Bannai and Kawai in Sleep and Biological Rhythms found that 3 grams of glycine before bed significantly improved sleep quality ratings, reduced next-day fatigue and sleepiness, and objectively improved polysomnography results, specifically increasing slow-wave sleep.

3 gramsbefore bed📍 sleep quality improvement in study subjects
Insufficient evidence to assessHigh confidence

The expert's claim specifically references a 2012 study by Bannai and Kawai published in Sleep and Biological Rhythms regarding glycine's effects on sleep quality, fatigue, and polysomnography (slow-w…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Evidence-backed claim

This was a randomized crossover study that gave 3 grams of glycine before bed to healthy volunteers and measured sleep architecture via polysomnography. The glycine group showed significant increases in slow-wave sleep — stage 3 non-REM sleep — and reductions in next-day fatigue and sleepiness.

Extracted claim

The Bannai et al. 2012 randomized crossover study found that 3 grams of glycine taken before bed significantly increased slow-wave sleep and reduced next-day fatigue and sleepiness in healthy volunteers.

3 gramsbefore bed📍 Given to healthy volunteers in a randomized crossover study
Insufficient evidence to assessHigh confidence

None of the 10 provided research sources correspond to the Bannai et al. 2012 randomized crossover study on glycine and sleep that the expert references. The provided literature includes reviews on gl…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Evidence-backed claim

The key study I want to point to is by Bannai and Kawai, published in 2012 in the journal Sleep and Biological Rhythms. They gave subjects 3 grams of glycine before bed and saw significant improvements in sleep quality ratings, reductions in fatigue and sleepiness the following day, and objective improvements in polysomnography — specifically increased slow-wave sleep, which is deep non-REM sleep.

Extracted claim

A 2012 study by Bannai and Kawai in Sleep and Biological Rhythms found that 3 grams of glycine before bed significantly improved sleep quality ratings, reduced next-day fatigue and sleepiness, and objectively improved polysomnography results, specifically increasing slow-wave sleep.

3 gramsbefore bed📍 sleep quality improvement in study subjects
Insufficient evidence to assessHigh confidence

None of the 10 retrieved studies directly address the Bannai and Kawai (2012) study cited by Huberman, nor do they provide evidence specifically examining glycine's effects on sleep quality, polysomno…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Evidence-backed claim

A 2019 paper by Ables and colleagues showed that adding glycine to a high-methionine diet in mice produced similar longevity outcomes to methionine restriction itself.

Extracted claim

A 2019 paper by Ables and colleagues showed that adding glycine to a high-methionine diet in mice produced similar longevity outcomes to methionine restriction itself.

Insufficient evidence to assessHigh confidence

None of the 10 published research studies listed above reference the Ables et al. 2019 paper on glycine supplementation in high-methionine diets and longevity outcomes in mice. While several studies i…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Evidence-backed claim

Glycine is generally recognized as safe by the FDA, and the therapeutic range in studies is typically 3 to 15 grams. At 3 grams for sleep, you're well within the safe range.

Extracted claim

Glycine is generally recognized as safe by the FDA, and the therapeutic range in studies is typically 3 to 15 grams, with 3 grams for sleep being well within the safe range.

3 grams📍 sleep; noted as well within safe range of 3–15 grams
Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly address glycine's FDA GRAS status, its therapeutic dosing range (3–15g), or its specific use at 3g for sleep improvement. While PMID 28337245 (a narrative revi…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Evidence-backed claim

Glycine is generally recognized as safe by the FDA, and the therapeutic range in studies is typically 3 to 15 grams. At 3 grams for sleep, you're well within the safe range.

Extracted claim

Glycine is generally recognized as safe by the FDA, and the therapeutic range in studies is typically 3 to 15 grams, with 3 grams for sleep being well within the safe range.

3 grams📍 sleep; noted as well within safe range of 3–15 grams
Insufficient evidence to assessHigh confidence

The provided research list does not contain studies that directly address glycine's FDA GRAS status, its dosage range for sleep (3g) or therapeutic applications (3–15g), or its safety profile in human…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Evidence-backed claim

A 2019 paper by Ables and colleagues showed that adding glycine to a high-methionine diet in mice produced similar longevity outcomes to methionine restriction itself.

Extracted claim

A 2019 paper by Ables and colleagues showed that adding glycine to a high-methionine diet in mice produced similar longevity outcomes to methionine restriction itself.

Insufficient evidence to assessHigh confidence

None of the 10 provided PubMed studies reference the 2019 Ables et al. paper on glycine supplementation in high-methionine diet mouse models, nor do any of them address methionine restriction, dietary…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Evidence-backed claim

The key study I want to point to is by Bannai and Kawai, published in 2012 in the journal Sleep and Biological Rhythms. They gave subjects 3 grams of glycine before bed and saw significant improvements in sleep quality ratings, reductions in fatigue and sleepiness the following day, and objective improvements in polysomnography — specifically increased slow-wave sleep, which is deep non-REM sleep.

Extracted claim

A 2012 study by Bannai and Kawai in Sleep and Biological Rhythms found that 3 grams of glycine before bed significantly improved sleep quality ratings, reduced next-day fatigue and sleepiness, and objectively improved polysomnography results, specifically increasing slow-wave sleep.

3 gramsbefore bed📍 sleep quality improvement in study subjects
Insufficient evidence to assessHigh confidence

None of the 10 retrieved studies directly address the Bannai and Kawai (2012) study cited by Huberman, nor do any of them examine glycine supplementation and sleep outcomes such as slow-wave sleep, fa…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Evidence-backed claim

This was a randomized crossover study that gave 3 grams of glycine before bed to healthy volunteers and measured sleep architecture via polysomnography. The glycine group showed significant increases in slow-wave sleep — stage 3 non-REM sleep — and reductions in next-day fatigue and sleepiness.

Extracted claim

The Bannai et al. 2012 randomized crossover study found that 3 grams of glycine taken before bed significantly increased slow-wave sleep and reduced next-day fatigue and sleepiness in healthy volunteers.

3 gramsbefore bed📍 Given to healthy volunteers in a randomized crossover study
Insufficient evidence to assessHigh confidence

None of the 10 provided research abstracts directly address the Bannai et al. 2012 study on glycine and slow-wave sleep, nor do any of the listed studies investigate glycine's effects on sleep quality…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Evidence-backed claim

The key study I want to point to is by Bannai and Kawai, published in 2012 in the journal Sleep and Biological Rhythms. They gave subjects 3 grams of glycine before bed and saw significant improvements in sleep quality ratings, reductions in fatigue and sleepiness the following day, and objective improvements in polysomnography — specifically increased slow-wave sleep, which is deep non-REM sleep.

Extracted claim

A 2012 study by Bannai and Kawai in Sleep and Biological Rhythms found that 3 grams of glycine before bed significantly improved sleep quality ratings, reduced next-day fatigue and sleepiness, and objectively improved polysomnography results, specifically increasing slow-wave sleep.

3 gramsbefore bed📍 sleep quality improvement in study subjects
Insufficient evidence to assessHigh confidence

The expert's claim specifically references a 2012 study by Bannai and Kawai published in Sleep and Biological Rhythms, but this study does not appear in any of the 10 provided PubMed references. While…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Evidence-backed claim

A 2019 paper by Ables and colleagues showed that adding glycine to a high-methionine diet in mice produced similar longevity outcomes to methionine restriction itself.

Extracted claim

A 2019 paper by Ables and colleagues showed that adding glycine to a high-methionine diet in mice produced similar longevity outcomes to methionine restriction itself.

Insufficient evidence to assessHigh confidence

None of the 10 provided studies are the 2019 Ables et al. paper referenced by the expert, nor do any of them investigate glycine supplementation in the context of methionine restriction or longevity o…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Evidence-backed claim

There's actually a clinical trial by Kumar et al. showing that supplementing with glycine and N-acetylcysteine in older adults significantly restored glutathione levels and improved several markers of oxidative stress and mitochondrial function.

Extracted claim

A clinical trial by Kumar et al. showed that supplementing with glycine and N-acetylcysteine in older adults significantly restored glutathione levels and improved markers of oxidative stress and mitochondrial function.

Insufficient evidence to assessHigh confidence

None of the 10 retrieved studies are the Kumar et al. clinical trial referenced in the expert's claim, nor do any of them investigate glycine and N-acetylcysteine (GlyNAC) supplementation in older adu…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Evidence-backed claim

There's actually a clinical trial by Kumar et al. showing that supplementing with glycine and N-acetylcysteine in older adults significantly restored glutathione levels and improved several markers of oxidative stress and mitochondrial function.

Extracted claim

A clinical trial by Kumar et al. showed that supplementing with glycine and N-acetylcysteine in older adults significantly restored glutathione levels and improved markers of oxidative stress and mitochondrial function.

Partially supportedHigh confidence

The claim aligns with PMID 35975308, an RCT whose title directly references GlyNAC supplementation in older adults improving glutathione deficiency, oxidative stress, mitochondrial dysfunction, and ag…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Evidence-backed claim

There's actually a clinical trial by Kumar et al. showing that supplementing with glycine and N-acetylcysteine in older adults significantly restored glutathione levels and improved several markers of oxidative stress and mitochondrial function.

Extracted claim

A clinical trial by Kumar et al. showed that supplementing with glycine and N-acetylcysteine in older adults significantly restored glutathione levels and improved markers of oxidative stress and mitochondrial function.

Insufficient evidence to assessHigh confidence

None of the 10 retrieved studies directly address the specific claim about glycine and N-acetylcysteine (GlyNAC) supplementation in older adults restoring glutathione levels or improving oxidative str…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Evidence-backed claim

A 2019 paper by Ables and colleagues showed that adding glycine to a high-methionine diet in mice produced similar longevity outcomes to methionine restriction itself.

Extracted claim

A 2019 paper by Ables and colleagues showed that adding glycine to a high-methionine diet in mice produced similar longevity outcomes to methionine restriction itself.

Insufficient evidence to assessHigh confidence

None of the 10 published research entries provided contain the Ables et al. 2019 study on glycine supplementation in high-methionine diet mice, nor any equivalent animal longevity study. While several…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Evidence-backed claim

This was a randomized crossover study that gave 3 grams of glycine before bed to healthy volunteers and measured sleep architecture via polysomnography. The glycine group showed significant increases in slow-wave sleep — stage 3 non-REM sleep — and reductions in next-day fatigue and sleepiness.

Extracted claim

The Bannai et al. 2012 randomized crossover study found that 3 grams of glycine taken before bed significantly increased slow-wave sleep and reduced next-day fatigue and sleepiness in healthy volunteers.

3 gramsbefore bed📍 Given to healthy volunteers in a randomized crossover study
Insufficient evidence to assessHigh confidence

None of the 10 provided research sources include or directly reference the Bannai et al. 2012 randomized crossover study on glycine and sleep that the expert cites. While PMID 37851316 is a systematic…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Evidence-backed claim

There's actually a clinical trial by Kumar et al. showing that supplementing with glycine and N-acetylcysteine in older adults significantly restored glutathione levels and improved several markers of oxidative stress and mitochondrial function.

Extracted claim

A clinical trial by Kumar et al. showed that supplementing with glycine and N-acetylcysteine in older adults significantly restored glutathione levels and improved markers of oxidative stress and mitochondrial function.

Supported by researchHigh confidence

The expert's claim is directly supported by PMID 35975308, an RCT explicitly titled 'Supplementing Glycine and N-Acetylcysteine (GlyNAC) in Older Adults Improves Glutathione Deficiency, Oxidative Stre…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Evidence-backed claim

A 2019 paper by Ables and colleagues showed that adding glycine to a high-methionine diet in mice produced similar longevity outcomes to methionine restriction itself.

Extracted claim

A 2019 paper by Ables and colleagues showed that adding glycine to a high-methionine diet in mice produced similar longevity outcomes to methionine restriction itself.

Insufficient evidence to assessHigh confidence

The expert's claim specifically references a 2019 paper by Ables and colleagues demonstrating that glycine supplementation in a high-methionine mouse diet mimics methionine restriction longevity outco…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Evidence-backed claim

There's actually a clinical trial by Kumar et al. showing that supplementing with glycine and N-acetylcysteine in older adults significantly restored glutathione levels and improved several markers of oxidative stress and mitochondrial function.

Extracted claim

A clinical trial by Kumar et al. showed that supplementing with glycine and N-acetylcysteine in older adults significantly restored glutathione levels and improved markers of oxidative stress and mitochondrial function.

Supported by researchHigh confidence

The expert's claim directly aligns with PMID 35975308, an RCT titled 'Supplementing Glycine and N-Acetylcysteine (GlyNAC) in Older Adults Improves Glutathione Deficiency, Oxidative Stress, Mitochondri…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Evidence-backed claim

There's actually a clinical trial by Kumar et al. showing that supplementing with glycine and N-acetylcysteine in older adults significantly restored glutathione levels and improved several markers of oxidative stress and mitochondrial function.

Extracted claim

A clinical trial by Kumar et al. showed that supplementing with glycine and N-acetylcysteine in older adults significantly restored glutathione levels and improved markers of oxidative stress and mitochondrial function.

Partially supportedHigh confidence

An RCT matching the described study (PMID: 35975308) is present in the literature list and its title directly aligns with the expert's claim, referencing GlyNAC supplementation in older adults and imp…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Evidence-backed claim

The key study I want to point to is by Bannai and Kawai, published in 2012 in the journal Sleep and Biological Rhythms. They gave subjects 3 grams of glycine before bed and saw significant improvements in sleep quality ratings, reductions in fatigue and sleepiness the following day, and objective improvements in polysomnography — specifically increased slow-wave sleep, which is deep non-REM sleep.

Extracted claim

A 2012 study by Bannai and Kawai in Sleep and Biological Rhythms found that 3 grams of glycine before bed significantly improved sleep quality ratings, reduced next-day fatigue and sleepiness, and objectively improved polysomnography results, specifically increasing slow-wave sleep.

3 gramsbefore bed📍 sleep quality improvement in study subjects
Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly address the Bannai and Kawai (2012) study cited by Huberman, nor do any of them evaluate glycine supplementation and sleep outcomes. The systematic review on g…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Evidence-backed claim

Glycine is generally recognized as safe by the FDA, and the therapeutic range in studies is typically 3 to 15 grams. At 3 grams for sleep, you're well within the safe range.

Extracted claim

Glycine is generally recognized as safe by the FDA, and the therapeutic range in studies is typically 3 to 15 grams, with 3 grams for sleep being well within the safe range.

3 grams📍 sleep; noted as well within safe range of 3–15 grams
Insufficient evidence to assessHigh confidence

The provided research corpus does not contain studies directly evaluating glycine's FDA GRAS status, its dosing range, or its specific effects on sleep at 3 grams. While PMID 37851316 (a systematic re…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Evidence-backed claim

Glycine is generally recognized as safe by the FDA, and the therapeutic range in studies is typically 3 to 15 grams. At 3 grams for sleep, you're well within the safe range.

Extracted claim

Glycine is generally recognized as safe by the FDA, and the therapeutic range in studies is typically 3 to 15 grams, with 3 grams for sleep being well within the safe range.

3 grams📍 sleep; noted as well within safe range of 3–15 grams
Insufficient evidence to assessHigh confidence

The provided research corpus does not contain studies that directly assess glycine's FDA GRAS status, its therapeutic dosage range, or its specific effects on sleep at 3 grams. While PMID 37851316 is…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Evidence-backed claim

This was a randomized crossover study that gave 3 grams of glycine before bed to healthy volunteers and measured sleep architecture via polysomnography. The glycine group showed significant increases in slow-wave sleep — stage 3 non-REM sleep — and reductions in next-day fatigue and sleepiness.

Extracted claim

The Bannai et al. 2012 randomized crossover study found that 3 grams of glycine taken before bed significantly increased slow-wave sleep and reduced next-day fatigue and sleepiness in healthy volunteers.

3 gramsbefore bed📍 Given to healthy volunteers in a randomized crossover study
Insufficient evidence to assessHigh confidence

The expert specifically cites the Bannai et al. 2012 study on glycine and sleep, but this study does not appear in the provided PubMed research list. None of the 10 listed studies address glycine's ef…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Mechanism discussion

It's co-agonist with glutamate at NMDA receptors, which is a slightly different role.

Extracted claim

Glycine is a co-agonist with glutamate at NMDA receptors.

Insufficient evidence to assessHigh confidence

None of the 10 listed studies directly address glycine's role as a co-agonist at NMDA receptors. The claim is a well-established pharmacological/neurochemical mechanism described in basic neuroscience…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

The body's endogenous production of glycine is estimated to cover only about a third of its total metabolic requirements, meaning dietary intake matters significantly.

Extracted claim

The body's endogenous production of glycine covers only about one third of its total metabolic requirements, making dietary intake significant.

Partially supportedHigh confidence

The claim that endogenous glycine production covers only approximately one-third of total metabolic requirements is a widely cited figure in nutritional biochemistry, and it is consistent with mechani…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

Part of methionine's potentially harmful effect at high intake is that it depletes glycine through the transsulfuration pathway. Supplementing glycine, particularly on high-protein diets with substantial meat intake, can effectively neutralize that imbalance.

Extracted claim

High methionine intake depletes glycine through the transsulfuration pathway, and supplementing glycine on high-protein diets with substantial meat intake can neutralize that imbalance.

Partially supportedHigh confidence

The mechanistic claim that high methionine intake depletes glycine through the transsulfuration pathway is a recognized biochemical pathway, and the glycine-related reviews (PMIDs 37510995, 28337245)…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

there's a growing argument that it may be conditionally essential, especially as we age or under high physiological demand

Extracted claim

Glycine may be conditionally essential, especially as we age or under high physiological demand, despite being classified as non-essential.

Partially supportedHigh confidence

The claim that glycine may be conditionally essential, particularly with aging or physiological stress, is partially supported by the available literature. The RCT by Sekhar et al. (PMID: 35975308) de…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

glycine promotes peripheral vasodilation, which facilitates the core body temperature drop required for sleep initiation.

Extracted claim

Glycine promotes peripheral vasodilation, which facilitates the core body temperature drop required for sleep initiation.

Insufficient evidence to assessHigh confidence

None of the 10 listed studies directly address the specific mechanistic claim that glycine promotes peripheral vasodilation to facilitate core body temperature drop for sleep initiation. The glycine-r…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

glycine is a key substrate in glutathione synthesis — the body's primary endogenous antioxidant. As glutathione production declines with age, ensuring adequate glycine and cysteine availability becomes more important.

Extracted claim

Glycine is a key substrate in glutathione synthesis, the body's primary endogenous antioxidant, and ensuring adequate glycine availability becomes more important as glutathione production declines with age.

Partially supportedHigh confidence

The claim has two components: (1) glycine as a substrate for glutathione synthesis, and (2) age-related decline in glutathione making glycine availability increasingly important. The RCT (PMID: 359753…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Mechanism discussion

glycine is also a precursor to creatine synthesis in the body and is critical for collagen formation. So there are potential secondary benefits beyond sleep.

Extracted claim

Glycine is a precursor to creatine synthesis in the body and is critical for collagen formation, providing potential secondary benefits beyond sleep.

Partially supportedHigh confidence

The claim that glycine is a precursor to creatine synthesis and critical for collagen formation is mechanistically well-established and receives indirect support from several studies in the provided l…

Mark Hyman
Mark Hyman
Cleveland Clinic Center for Functional Medicine
Mechanism discussion

the beautiful thing about um protein is it's full of other good things like B vitamins amino acids glycine torine cysteine methine all critical

Extracted claim

Protein foods contain glycine along with other amino acids that are critical for health.

Supported by researchHigh confidence

Multiple reviews in the provided literature directly support the claim that glycine is an amino acid found in protein-containing foods and is critical for health. The systematic review (PMID: 37851316…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

The body's endogenous production of glycine is estimated to cover only about a third of its total metabolic requirements, meaning dietary intake matters significantly.

Extracted claim

The body's endogenous production of glycine covers only about one third of its total metabolic requirements, making dietary intake significant.

Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly address the specific claim that endogenous glycine synthesis covers only approximately one-third of total metabolic requirements. While some studies (PMIDs 283…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Mechanism discussion

glycine is also a precursor to creatine synthesis in the body and is critical for collagen formation. So there are potential secondary benefits beyond sleep.

Extracted claim

Glycine is a precursor to creatine synthesis in the body and is critical for collagen formation, providing potential secondary benefits beyond sleep.

Partially supportedHigh confidence

The claim that glycine is a precursor to creatine synthesis is biochemically well-established and is consistent with the review on creatine (PMID: 17430086), which covers endogenous creatine metabolis…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Mechanism discussion

methionine — the amino acid found abundantly in meat — requires glycine for its metabolism. People who eat a lot of animal protein may have relatively higher glycine needs, and supplementing may help balance that ratio.

Extracted claim

Methionine, found abundantly in meat, requires glycine for its metabolism, meaning people who eat a lot of animal protein may have relatively higher glycine needs and supplementing may help balance that ratio.

Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly address the specific mechanistic claim that methionine metabolism requires glycine and that high meat consumption elevates glycine needs. The retrieved literat…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

there's a growing argument that it may be conditionally essential, especially as we age or under high physiological demand

Extracted claim

Glycine may be conditionally essential, especially as we age or under high physiological demand, despite being classified as non-essential.

Partially supportedHigh confidence

The claim that glycine may be conditionally essential, particularly with aging or under physiological stress, finds indirect support from the provided literature. The GlyNAC RCT (PMID: 35975308) is th…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

Part of methionine's potentially harmful effect at high intake is that it depletes glycine through the transsulfuration pathway. Supplementing glycine, particularly on high-protein diets with substantial meat intake, can effectively neutralize that imbalance.

Extracted claim

High methionine intake depletes glycine through the transsulfuration pathway, and supplementing glycine on high-protein diets with substantial meat intake can neutralize that imbalance.

Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly address the mechanistic claim that high methionine intake depletes glycine via the transsulfuration pathway or that glycine supplementation neutralizes this im…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

glycine is a key substrate in glutathione synthesis — the body's primary endogenous antioxidant. As glutathione production declines with age, ensuring adequate glycine and cysteine availability becomes more important.

Extracted claim

Glycine is a key substrate in glutathione synthesis, the body's primary endogenous antioxidant, and ensuring adequate glycine availability becomes more important as glutathione production declines with age.

Partially supportedHigh confidence

The mechanistic claim that glycine is a key substrate in glutathione synthesis is well-established biochemistry, and the RCT (PMID: 35975308) on GlyNAC supplementation in older adults directly support…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

glycine promotes peripheral vasodilation, which facilitates the core body temperature drop required for sleep initiation.

Extracted claim

Glycine promotes peripheral vasodilation, which facilitates the core body temperature drop required for sleep initiation.

Insufficient evidence to assessHigh confidence

None of the 10 retrieved studies address the specific mechanistic claim that glycine promotes peripheral vasodilation to facilitate core body temperature drop for sleep initiation. The provided litera…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

Glycine is also the most abundant amino acid in collagen, comprising about 33% of its total content. For skin aging, joint health, and gut mucosal integrity, maintaining adequate glycine intake to support collagen synthesis is relevant.

Extracted claim

Glycine is the most abundant amino acid in collagen, comprising about 33% of its total content, and is relevant for skin aging, joint health, and gut mucosal integrity.

Insufficient evidence to assessHigh confidence

The expert's claim that glycine comprises approximately 33% of collagen's amino acid content and is relevant for skin aging, joint health, and gut mucosal integrity is a well-established biochemical f…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Mechanism discussion

when you take 3 grams of glycine before bed, it facilitates a reduction in core body temperature by promoting heat dissipation through peripheral vasodilation.

Extracted claim

Taking 3 grams of glycine before bed facilitates a reduction in core body temperature by promoting heat dissipation through peripheral vasodilation.

3 gramsbefore bed📍 sleep optimization
Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly address the claim that 3 grams of glycine before bed reduces core body temperature via peripheral vasodilation. The retrieved literature covers topics such as…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Mechanism discussion

Glycine is an inhibitory neurotransmitter in the central nervous system — it acts on glycine receptors in the brainstem and spinal cord to reduce neuronal excitability.

Extracted claim

Glycine is an inhibitory neurotransmitter in the central nervous system that acts on glycine receptors in the brainstem and spinal cord to reduce neuronal excitability.

Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly address Huberman's mechanistic claim about glycine as an inhibitory neurotransmitter acting on glycine receptors in the brainstem and spinal cord. The studies…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Mechanism discussion

It's co-agonist with glutamate at NMDA receptors, which is a slightly different role.

Extracted claim

Glycine is a co-agonist with glutamate at NMDA receptors.

Insufficient evidence to assessHigh confidence

The expert's claim that glycine acts as a co-agonist with glutamate at NMDA receptors is a well-established neuropharmacological mechanism described extensively in basic science literature, but none o…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

The body's endogenous production of glycine is estimated to cover only about a third of its total metabolic requirements, meaning dietary intake matters significantly.

Extracted claim

The body's endogenous production of glycine covers only about one third of its total metabolic requirements, making dietary intake significant.

Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly address the claim that endogenous glycine synthesis covers only approximately one-third of total metabolic requirements. While several studies are tangentially…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

glycine is a key substrate in glutathione synthesis — the body's primary endogenous antioxidant. As glutathione production declines with age, ensuring adequate glycine and cysteine availability becomes more important.

Extracted claim

Glycine is a key substrate in glutathione synthesis, the body's primary endogenous antioxidant, and ensuring adequate glycine availability becomes more important as glutathione production declines with age.

Partially supportedHigh confidence

The mechanistic claim that glycine is a substrate for glutathione synthesis is well-established biochemistry, and PMID 35975308 (an RCT on GlyNAC supplementation in older adults) directly investigates…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Mechanism discussion

It's co-agonist with glutamate at NMDA receptors, which is a slightly different role.

Extracted claim

Glycine is a co-agonist with glutamate at NMDA receptors.

Insufficient evidence to assessHigh confidence

None of the 10 provided studies address the mechanistic claim that glycine acts as a co-agonist with glutamate at NMDA receptors. The retrieved literature focuses on topics such as GlyNAC supplementat…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

there's a growing argument that it may be conditionally essential, especially as we age or under high physiological demand

Extracted claim

Glycine may be conditionally essential, especially as we age or under high physiological demand, despite being classified as non-essential.

Partially supportedHigh confidence

The GlyNAC RCT (PMID: 35975308) provides the most directly relevant evidence, demonstrating that glycine supplementation in older adults improved glutathione deficiency, oxidative stress, mitochondria…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

Part of methionine's potentially harmful effect at high intake is that it depletes glycine through the transsulfuration pathway. Supplementing glycine, particularly on high-protein diets with substantial meat intake, can effectively neutralize that imbalance.

Extracted claim

High methionine intake depletes glycine through the transsulfuration pathway, and supplementing glycine on high-protein diets with substantial meat intake can neutralize that imbalance.

Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly address the mechanistic claim that high methionine intake depletes glycine via the transsulfuration pathway, nor do any evaluate glycine supplementation as a c…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

glycine promotes peripheral vasodilation, which facilitates the core body temperature drop required for sleep initiation.

Extracted claim

Glycine promotes peripheral vasodilation, which facilitates the core body temperature drop required for sleep initiation.

Insufficient evidence to assessHigh confidence

None of the 10 retrieved studies directly address the specific mechanistic claim that glycine promotes peripheral vasodilation to facilitate core body temperature drop for sleep initiation. The availa…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

Glycine is also the most abundant amino acid in collagen, comprising about 33% of its total content. For skin aging, joint health, and gut mucosal integrity, maintaining adequate glycine intake to support collagen synthesis is relevant.

Extracted claim

Glycine is the most abundant amino acid in collagen, comprising about 33% of its total content, and is relevant for skin aging, joint health, and gut mucosal integrity.

Insufficient evidence to assessHigh confidence

The expert's claim that glycine comprises approximately 33% of collagen and is relevant for skin aging, joint health, and gut mucosal integrity is a well-established biochemical fact supported by deca…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Mechanism discussion

when you take 3 grams of glycine before bed, it facilitates a reduction in core body temperature by promoting heat dissipation through peripheral vasodilation.

Extracted claim

Taking 3 grams of glycine before bed facilitates a reduction in core body temperature by promoting heat dissipation through peripheral vasodilation.

3 gramsbefore bed📍 sleep optimization
Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly investigate the claim that 3 grams of glycine before bed reduces core body temperature via peripheral vasodilation. The available literature covers topics such…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Mechanism discussion

glycine is also a precursor to creatine synthesis in the body and is critical for collagen formation. So there are potential secondary benefits beyond sleep.

Extracted claim

Glycine is a precursor to creatine synthesis in the body and is critical for collagen formation, providing potential secondary benefits beyond sleep.

Partially supportedHigh confidence

The claim that glycine is a precursor to creatine synthesis is consistent with established biochemistry, and PMID 17430086 (a review on creatine as an endogenous metabolite) would be expected to addre…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Mechanism discussion

Glycine is an inhibitory neurotransmitter in the central nervous system — it acts on glycine receptors in the brainstem and spinal cord to reduce neuronal excitability.

Extracted claim

Glycine is an inhibitory neurotransmitter in the central nervous system that acts on glycine receptors in the brainstem and spinal cord to reduce neuronal excitability.

Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly examine glycine's role as an inhibitory neurotransmitter acting on glycine receptors in the brainstem and spinal cord. The studies focus on topics such as GlyN…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Mechanism discussion

methionine — the amino acid found abundantly in meat — requires glycine for its metabolism. People who eat a lot of animal protein may have relatively higher glycine needs, and supplementing may help balance that ratio.

Extracted claim

Methionine, found abundantly in meat, requires glycine for its metabolism, meaning people who eat a lot of animal protein may have relatively higher glycine needs and supplementing may help balance that ratio.

Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly address the mechanistic claim that methionine metabolism requires glycine, or that high animal protein intake elevates glycine needs. The listed papers cover t…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

glycine promotes peripheral vasodilation, which facilitates the core body temperature drop required for sleep initiation.

Extracted claim

Glycine promotes peripheral vasodilation, which facilitates the core body temperature drop required for sleep initiation.

Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly investigate the specific mechanistic claim that glycine promotes peripheral vasodilation to facilitate core body temperature drop for sleep initiation. The mos…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Mechanism discussion

Glycine is an inhibitory neurotransmitter in the central nervous system — it acts on glycine receptors in the brainstem and spinal cord to reduce neuronal excitability.

Extracted claim

Glycine is an inhibitory neurotransmitter in the central nervous system that acts on glycine receptors in the brainstem and spinal cord to reduce neuronal excitability.

Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly address the mechanistic claim that glycine acts as an inhibitory neurotransmitter via glycine receptors in the brainstem and spinal cord. While PMID 37851316 i…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Mechanism discussion

glycine is also a precursor to creatine synthesis in the body and is critical for collagen formation. So there are potential secondary benefits beyond sleep.

Extracted claim

Glycine is a precursor to creatine synthesis in the body and is critical for collagen formation, providing potential secondary benefits beyond sleep.

Insufficient evidence to assessHigh confidence

The expert's claim that glycine is a precursor to creatine synthesis and critical for collagen formation is a well-established biochemical fact, but the provided research corpus does not directly eval…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

glycine is a key substrate in glutathione synthesis — the body's primary endogenous antioxidant. As glutathione production declines with age, ensuring adequate glycine and cysteine availability becomes more important.

Extracted claim

Glycine is a key substrate in glutathione synthesis, the body's primary endogenous antioxidant, and ensuring adequate glycine availability becomes more important as glutathione production declines with age.

Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly address the claim that glycine is a key substrate in glutathione synthesis or that glutathione production declines with age in relation to glycine availability…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

glycine promotes peripheral vasodilation, which facilitates the core body temperature drop required for sleep initiation.

Extracted claim

Glycine promotes peripheral vasodilation, which facilitates the core body temperature drop required for sleep initiation.

Insufficient evidence to assessHigh confidence

None of the 10 retrieved studies directly address the specific mechanistic claim that glycine promotes peripheral vasodilation to facilitate core body temperature drop for sleep initiation. The most r…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

Part of methionine's potentially harmful effect at high intake is that it depletes glycine through the transsulfuration pathway. Supplementing glycine, particularly on high-protein diets with substantial meat intake, can effectively neutralize that imbalance.

Extracted claim

High methionine intake depletes glycine through the transsulfuration pathway, and supplementing glycine on high-protein diets with substantial meat intake can neutralize that imbalance.

Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly address the mechanistic claim about methionine depleting glycine via the transsulfuration pathway or the therapeutic rationale for glycine supplementation on h…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Mechanism discussion

It's co-agonist with glutamate at NMDA receptors, which is a slightly different role.

Extracted claim

Glycine is a co-agonist with glutamate at NMDA receptors.

Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly address the mechanistic claim that glycine acts as a co-agonist with glutamate at NMDA receptors. The retrieved literature covers topics such as bone broth, br…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

there's a growing argument that it may be conditionally essential, especially as we age or under high physiological demand

Extracted claim

Glycine may be conditionally essential, especially as we age or under high physiological demand, despite being classified as non-essential.

Insufficient evidence to assessHigh confidence

The provided research corpus does not contain studies directly addressing the conditional essentiality of glycine with aging or under physiological stress. While PMID 37851316 (a systematic review on…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

The body's endogenous production of glycine is estimated to cover only about a third of its total metabolic requirements, meaning dietary intake matters significantly.

Extracted claim

The body's endogenous production of glycine covers only about one third of its total metabolic requirements, making dietary intake significant.

Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly address the specific mechanistic claim that endogenous glycine synthesis covers only approximately one-third of total metabolic requirements. While PMID 375109…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

Part of methionine's potentially harmful effect at high intake is that it depletes glycine through the transsulfuration pathway. Supplementing glycine, particularly on high-protein diets with substantial meat intake, can effectively neutralize that imbalance.

Extracted claim

High methionine intake depletes glycine through the transsulfuration pathway, and supplementing glycine on high-protein diets with substantial meat intake can neutralize that imbalance.

Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly address the mechanistic claim about methionine depleting glycine via the transsulfuration pathway, nor do any examine glycine supplementation in the context of…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

Glycine is also the most abundant amino acid in collagen, comprising about 33% of its total content. For skin aging, joint health, and gut mucosal integrity, maintaining adequate glycine intake to support collagen synthesis is relevant.

Extracted claim

Glycine is the most abundant amino acid in collagen, comprising about 33% of its total content, and is relevant for skin aging, joint health, and gut mucosal integrity.

Insufficient evidence to assessHigh confidence

None of the provided studies directly address the specific claim that glycine constitutes approximately 33% of collagen's amino acid content, nor do they directly test the mechanistic links between gl…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

glycine is a key substrate in glutathione synthesis — the body's primary endogenous antioxidant. As glutathione production declines with age, ensuring adequate glycine and cysteine availability becomes more important.

Extracted claim

Glycine is a key substrate in glutathione synthesis, the body's primary endogenous antioxidant, and ensuring adequate glycine availability becomes more important as glutathione production declines with age.

Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly address the claim that glycine is a key substrate in glutathione synthesis or that glutathione production declines with age in a way that increases glycine req…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Mechanism discussion

when you take 3 grams of glycine before bed, it facilitates a reduction in core body temperature by promoting heat dissipation through peripheral vasodilation.

Extracted claim

Taking 3 grams of glycine before bed facilitates a reduction in core body temperature by promoting heat dissipation through peripheral vasodilation.

3 gramsbefore bed📍 sleep optimization
Insufficient evidence to assessHigh confidence

None of the 10 retrieved studies directly address the specific mechanistic claim that 3 grams of glycine before bed reduces core body temperature via peripheral vasodilation. The only potentially rele…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Mechanism discussion

methionine — the amino acid found abundantly in meat — requires glycine for its metabolism. People who eat a lot of animal protein may have relatively higher glycine needs, and supplementing may help balance that ratio.

Extracted claim

Methionine, found abundantly in meat, requires glycine for its metabolism, meaning people who eat a lot of animal protein may have relatively higher glycine needs and supplementing may help balance that ratio.

Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly address the mechanistic claim that methionine metabolism requires glycine or that high animal protein intake increases relative glycine needs. While PMID 37851…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Mechanism discussion

when you take 3 grams of glycine before bed, it facilitates a reduction in core body temperature by promoting heat dissipation through peripheral vasodilation.

Extracted claim

Taking 3 grams of glycine before bed facilitates a reduction in core body temperature by promoting heat dissipation through peripheral vasodilation.

3 gramsbefore bed📍 sleep optimization
Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly address the specific claim that 3 grams of glycine before bed reduces core body temperature via peripheral vasodilation. The most relevant study (PMID: 3785131…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Mechanism discussion

It's co-agonist with glutamate at NMDA receptors, which is a slightly different role.

Extracted claim

Glycine is a co-agonist with glutamate at NMDA receptors.

Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly address the mechanistic claim that glycine acts as a co-agonist with glutamate at NMDA receptors. The retrieved literature covers topics such as bone broth, br…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

The body's endogenous production of glycine is estimated to cover only about a third of its total metabolic requirements, meaning dietary intake matters significantly.

Extracted claim

The body's endogenous production of glycine covers only about one third of its total metabolic requirements, making dietary intake significant.

Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly address the claim that endogenous glycine synthesis covers only approximately one-third of total metabolic requirements. While PMID 37510995 ('Glycine: The Sma…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

there's a growing argument that it may be conditionally essential, especially as we age or under high physiological demand

Extracted claim

Glycine may be conditionally essential, especially as we age or under high physiological demand, despite being classified as non-essential.

Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly address the claim that glycine may be conditionally essential with aging or under high physiological demand. While PMID 37851316 (a systematic review on glycin…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

Glycine is also the most abundant amino acid in collagen, comprising about 33% of its total content. For skin aging, joint health, and gut mucosal integrity, maintaining adequate glycine intake to support collagen synthesis is relevant.

Extracted claim

Glycine is the most abundant amino acid in collagen, comprising about 33% of its total content, and is relevant for skin aging, joint health, and gut mucosal integrity.

Insufficient evidence to assessHigh confidence

None of the 10 retrieved studies directly address the specific claim that glycine comprises approximately 33% of collagen's amino acid content, nor do they directly evaluate glycine's roles in skin ag…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Mechanism discussion

glycine is also a precursor to creatine synthesis in the body and is critical for collagen formation. So there are potential secondary benefits beyond sleep.

Extracted claim

Glycine is a precursor to creatine synthesis in the body and is critical for collagen formation, providing potential secondary benefits beyond sleep.

Insufficient evidence to assessHigh confidence

The expert's claim that glycine is a precursor to creatine synthesis and critical for collagen formation is a well-established biochemical fact, but the provided research corpus does not directly eval…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Mechanism discussion

Glycine is an inhibitory neurotransmitter in the central nervous system — it acts on glycine receptors in the brainstem and spinal cord to reduce neuronal excitability.

Extracted claim

Glycine is an inhibitory neurotransmitter in the central nervous system that acts on glycine receptors in the brainstem and spinal cord to reduce neuronal excitability.

Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly address the claim that glycine acts as an inhibitory neurotransmitter via glycine receptors in the brainstem and spinal cord. The closest potentially relevant…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Mechanism discussion

methionine — the amino acid found abundantly in meat — requires glycine for its metabolism. People who eat a lot of animal protein may have relatively higher glycine needs, and supplementing may help balance that ratio.

Extracted claim

Methionine, found abundantly in meat, requires glycine for its metabolism, meaning people who eat a lot of animal protein may have relatively higher glycine needs and supplementing may help balance that ratio.

Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly address the mechanistic claim that methionine metabolism requires glycine, or that high animal protein intake elevates glycine needs. While PMID 37851316 (a sy…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Mechanism discussion

It's co-agonist with glutamate at NMDA receptors, which is a slightly different role.

Extracted claim

Glycine is a co-agonist with glutamate at NMDA receptors.

Insufficient evidence to assessHigh confidence

None of the 10 published research articles provided address glycine's role as a co-agonist at NMDA receptors. The glycine-related studies focus on anti-inflammatory properties (PMID: 37510995, 2833724…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Mechanism discussion

when you take 3 grams of glycine before bed, it facilitates a reduction in core body temperature by promoting heat dissipation through peripheral vasodilation.

Extracted claim

Taking 3 grams of glycine before bed facilitates a reduction in core body temperature by promoting heat dissipation through peripheral vasodilation.

3 gramsbefore bed📍 sleep optimization
Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly examine the claim that 3g of glycine before bed reduces core body temperature via peripheral vasodilation. The most potentially relevant study (PMID: 37851316)…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Mechanism discussion

methionine — the amino acid found abundantly in meat — requires glycine for its metabolism. People who eat a lot of animal protein may have relatively higher glycine needs, and supplementing may help balance that ratio.

Extracted claim

Methionine, found abundantly in meat, requires glycine for its metabolism, meaning people who eat a lot of animal protein may have relatively higher glycine needs and supplementing may help balance that ratio.

Insufficient evidence to assessHigh confidence

None of the 10 retrieved studies directly address the mechanistic claim that methionine metabolism requires glycine and that high animal protein consumers may have elevated glycine needs. The retrieve…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Mechanism discussion

glycine is also a precursor to creatine synthesis in the body and is critical for collagen formation. So there are potential secondary benefits beyond sleep.

Extracted claim

Glycine is a precursor to creatine synthesis in the body and is critical for collagen formation, providing potential secondary benefits beyond sleep.

Insufficient evidence to assessHigh confidence

The expert's claim that glycine is a precursor to creatine synthesis and critical for collagen formation is biochemically well-established in the scientific literature, but the provided studies do not…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Mechanism discussion

It's co-agonist with glutamate at NMDA receptors, which is a slightly different role.

Extracted claim

Glycine is a co-agonist with glutamate at NMDA receptors.

Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly address glycine's role as a co-agonist at NMDA receptors. The claim is a well-established neuroscience mechanistic fact documented extensively in pharmacology…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

Part of methionine's potentially harmful effect at high intake is that it depletes glycine through the transsulfuration pathway. Supplementing glycine, particularly on high-protein diets with substantial meat intake, can effectively neutralize that imbalance.

Extracted claim

High methionine intake depletes glycine through the transsulfuration pathway, and supplementing glycine on high-protein diets with substantial meat intake can neutralize that imbalance.

Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly address the mechanistic claim that high methionine intake depletes glycine via the transsulfuration pathway, nor do they evaluate glycine supplementation as a…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

glycine promotes peripheral vasodilation, which facilitates the core body temperature drop required for sleep initiation.

Extracted claim

Glycine promotes peripheral vasodilation, which facilitates the core body temperature drop required for sleep initiation.

Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly address the claimed mechanism that glycine promotes peripheral vasodilation to facilitate core body temperature drop for sleep initiation. The closest potentia…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

glycine is a key substrate in glutathione synthesis — the body's primary endogenous antioxidant. As glutathione production declines with age, ensuring adequate glycine and cysteine availability becomes more important.

Extracted claim

Glycine is a key substrate in glutathione synthesis, the body's primary endogenous antioxidant, and ensuring adequate glycine availability becomes more important as glutathione production declines with age.

Insufficient evidence to assessHigh confidence

None of the 10 retrieved studies directly address the claim that glycine is a key substrate in glutathione synthesis or that glutathione production declines with age in a way that increases glycine's…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

there's a growing argument that it may be conditionally essential, especially as we age or under high physiological demand

Extracted claim

Glycine may be conditionally essential, especially as we age or under high physiological demand, despite being classified as non-essential.

Insufficient evidence to assessHigh confidence

None of the provided studies directly address the conditional essentiality of glycine with aging or under high physiological demand. The systematic review on glycine administration (PMID: 37851316) is…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

Glycine is also the most abundant amino acid in collagen, comprising about 33% of its total content. For skin aging, joint health, and gut mucosal integrity, maintaining adequate glycine intake to support collagen synthesis is relevant.

Extracted claim

Glycine is the most abundant amino acid in collagen, comprising about 33% of its total content, and is relevant for skin aging, joint health, and gut mucosal integrity.

Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly address the specific claim that glycine comprises approximately 33% of collagen's amino acid content, nor do they directly investigate glycine's mechanistic ro…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

The body's endogenous production of glycine is estimated to cover only about a third of its total metabolic requirements, meaning dietary intake matters significantly.

Extracted claim

The body's endogenous production of glycine covers only about one third of its total metabolic requirements, making dietary intake significant.

Insufficient evidence to assessHigh confidence

None of the 10 retrieved studies directly address the claim that endogenous glycine synthesis meets only approximately one-third of the body's total metabolic requirements. The studies provided includ…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Mechanism discussion

Glycine is an inhibitory neurotransmitter in the central nervous system — it acts on glycine receptors in the brainstem and spinal cord to reduce neuronal excitability.

Extracted claim

Glycine is an inhibitory neurotransmitter in the central nervous system that acts on glycine receptors in the brainstem and spinal cord to reduce neuronal excitability.

Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly address the mechanistic claim that glycine acts as an inhibitory neurotransmitter via glycine receptors in the brainstem and spinal cord. The closest potential…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

The body's endogenous production of glycine is estimated to cover only about a third of its total metabolic requirements, meaning dietary intake matters significantly.

Extracted claim

The body's endogenous production of glycine covers only about one third of its total metabolic requirements, making dietary intake significant.

Partially supportedHigh confidence

The claim that endogenous glycine production covers only about one-third of total metabolic requirements is a well-cited figure in the glycine literature, and the provided reviews (PMIDs 37510995 and…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

glycine promotes peripheral vasodilation, which facilitates the core body temperature drop required for sleep initiation.

Extracted claim

Glycine promotes peripheral vasodilation, which facilitates the core body temperature drop required for sleep initiation.

Insufficient evidence to assessHigh confidence

None of the 10 listed studies directly address the mechanism of glycine-induced peripheral vasodilation as a pathway to core body temperature reduction and sleep initiation. While glycine's anti-infla…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Mechanism discussion

when you take 3 grams of glycine before bed, it facilitates a reduction in core body temperature by promoting heat dissipation through peripheral vasodilation.

Extracted claim

Taking 3 grams of glycine before bed facilitates a reduction in core body temperature by promoting heat dissipation through peripheral vasodilation.

3 gramsbefore bed📍 sleep optimization
Insufficient evidence to assessHigh confidence

None of the 10 published research papers listed above directly address the specific mechanistic claim that 3 grams of glycine before bed reduces core body temperature via peripheral vasodilation. Whil…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

Part of methionine's potentially harmful effect at high intake is that it depletes glycine through the transsulfuration pathway. Supplementing glycine, particularly on high-protein diets with substantial meat intake, can effectively neutralize that imbalance.

Extracted claim

High methionine intake depletes glycine through the transsulfuration pathway, and supplementing glycine on high-protein diets with substantial meat intake can neutralize that imbalance.

Insufficient evidence to assessHigh confidence

The provided research does not directly address the specific mechanistic claim that high methionine intake depletes glycine via the transsulfuration pathway. The glycine-related reviews (PMIDs 3751099…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Mechanism discussion

when you take 3 grams of glycine before bed, it facilitates a reduction in core body temperature by promoting heat dissipation through peripheral vasodilation.

Extracted claim

Taking 3 grams of glycine before bed facilitates a reduction in core body temperature by promoting heat dissipation through peripheral vasodilation.

3 gramsbefore bed📍 sleep optimization
Insufficient evidence to assessHigh confidence

None of the 10 listed studies directly examine glycine supplementation's effect on core body temperature reduction or peripheral vasodilation as a sleep-facilitating mechanism. While glycine appears i…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Mechanism discussion

It's co-agonist with glutamate at NMDA receptors, which is a slightly different role.

Extracted claim

Glycine is a co-agonist with glutamate at NMDA receptors.

Insufficient evidence to assessHigh confidence

None of the 10 published research articles provided address glycine's role as a co-agonist at NMDA receptors. The glycine-related studies (PMIDs 37510995, 28337245, 35975308) focus on anti-inflammator…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Mechanism discussion

Glycine is an inhibitory neurotransmitter in the central nervous system — it acts on glycine receptors in the brainstem and spinal cord to reduce neuronal excitability.

Extracted claim

Glycine is an inhibitory neurotransmitter in the central nervous system that acts on glycine receptors in the brainstem and spinal cord to reduce neuronal excitability.

Insufficient evidence to assessHigh confidence

The expert's claim describes a well-established neurophysiological mechanism — glycine acting as an inhibitory neurotransmitter via glycine receptors in the brainstem and spinal cord — but none of the…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Mechanism discussion

Glycine is an inhibitory neurotransmitter in the central nervous system — it acts on glycine receptors in the brainstem and spinal cord to reduce neuronal excitability.

Extracted claim

Glycine is an inhibitory neurotransmitter in the central nervous system that acts on glycine receptors in the brainstem and spinal cord to reduce neuronal excitability.

Insufficient evidence to assessHigh confidence

The expert's claim is a well-established neurophysiological fact regarding glycine's role as an inhibitory neurotransmitter acting on glycine receptors in the brainstem and spinal cord. However, none…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Mechanism discussion

glycine is also a precursor to creatine synthesis in the body and is critical for collagen formation. So there are potential secondary benefits beyond sleep.

Extracted claim

Glycine is a precursor to creatine synthesis in the body and is critical for collagen formation, providing potential secondary benefits beyond sleep.

Partially supportedHigh confidence

The claim that glycine is a precursor to creatine synthesis is supported mechanistically by the creatine review (PMID: 17430086), which covers creatine's biosynthesis from glycine, arginine, and methi…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Mechanism discussion

methionine — the amino acid found abundantly in meat — requires glycine for its metabolism. People who eat a lot of animal protein may have relatively higher glycine needs, and supplementing may help balance that ratio.

Extracted claim

Methionine, found abundantly in meat, requires glycine for its metabolism, meaning people who eat a lot of animal protein may have relatively higher glycine needs and supplementing may help balance that ratio.

Insufficient evidence to assessHigh confidence

The expert's claim concerns a specific biochemical mechanism—that dietary methionine (abundant in animal protein) requires glycine for its metabolism, thereby increasing glycine needs in high meat con…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

there's a growing argument that it may be conditionally essential, especially as we age or under high physiological demand

Extracted claim

Glycine may be conditionally essential, especially as we age or under high physiological demand, despite being classified as non-essential.

Partially supportedHigh confidence

The claim that glycine may be conditionally essential under certain physiological conditions receives indirect support from multiple sources in the provided literature. The GlyNAC RCT (PMID: 35975308)…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

glycine promotes peripheral vasodilation, which facilitates the core body temperature drop required for sleep initiation.

Extracted claim

Glycine promotes peripheral vasodilation, which facilitates the core body temperature drop required for sleep initiation.

Insufficient evidence to assessHigh confidence

None of the 10 listed studies directly address the specific mechanistic claim that glycine promotes peripheral vasodilation to facilitate core body temperature drop for sleep initiation. While two rev…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

glycine is a key substrate in glutathione synthesis — the body's primary endogenous antioxidant. As glutathione production declines with age, ensuring adequate glycine and cysteine availability becomes more important.

Extracted claim

Glycine is a key substrate in glutathione synthesis, the body's primary endogenous antioxidant, and ensuring adequate glycine availability becomes more important as glutathione production declines with age.

Partially supportedHigh confidence

The claim that glycine is a key substrate in glutathione synthesis and that its importance increases with age is partially supported by the provided literature. The GlyNAC RCT (PMID: 35975308) directl…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

The body's endogenous production of glycine is estimated to cover only about a third of its total metabolic requirements, meaning dietary intake matters significantly.

Extracted claim

The body's endogenous production of glycine covers only about one third of its total metabolic requirements, making dietary intake significant.

Partially supportedHigh confidence

The claim that endogenous glycine production covers only about one-third of total metabolic requirements is a specific quantitative mechanistic assertion. The review 'Multifarious Beneficial Effect of…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

Glycine is also the most abundant amino acid in collagen, comprising about 33% of its total content. For skin aging, joint health, and gut mucosal integrity, maintaining adequate glycine intake to support collagen synthesis is relevant.

Extracted claim

Glycine is the most abundant amino acid in collagen, comprising about 33% of its total content, and is relevant for skin aging, joint health, and gut mucosal integrity.

Partially supportedHigh confidence

The claim that glycine is the most abundant amino acid in collagen (~33%) is a well-established biochemical fact consistent with the review literature provided (PMIDs 28337245, 37510995, 40180691). Th…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

Glycine is also the most abundant amino acid in collagen, comprising about 33% of its total content. For skin aging, joint health, and gut mucosal integrity, maintaining adequate glycine intake to support collagen synthesis is relevant.

Extracted claim

Glycine is the most abundant amino acid in collagen, comprising about 33% of its total content, and is relevant for skin aging, joint health, and gut mucosal integrity.

Partially supportedHigh confidence

The claim that glycine is the most abundant amino acid in collagen (~33%) is a well-established biochemical fact consistent with the mechanistic background in the provided literature. The review 'Mult…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

glycine is a key substrate in glutathione synthesis — the body's primary endogenous antioxidant. As glutathione production declines with age, ensuring adequate glycine and cysteine availability becomes more important.

Extracted claim

Glycine is a key substrate in glutathione synthesis, the body's primary endogenous antioxidant, and ensuring adequate glycine availability becomes more important as glutathione production declines with age.

Partially supportedHigh confidence

The RCT (PMID: 35975308) on GlyNAC supplementation in older adults directly supports the claim by demonstrating that supplementing glycine (alongside N-acetylcysteine) improves glutathione deficiency…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

there's a growing argument that it may be conditionally essential, especially as we age or under high physiological demand

Extracted claim

Glycine may be conditionally essential, especially as we age or under high physiological demand, despite being classified as non-essential.

Partially supportedHigh confidence

The claim that glycine may be conditionally essential under physiological stress or aging is plausible and partially supported by the available literature. The RCT (PMID: 35975308) on GlyNAC supplemen…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

Part of methionine's potentially harmful effect at high intake is that it depletes glycine through the transsulfuration pathway. Supplementing glycine, particularly on high-protein diets with substantial meat intake, can effectively neutralize that imbalance.

Extracted claim

High methionine intake depletes glycine through the transsulfuration pathway, and supplementing glycine on high-protein diets with substantial meat intake can neutralize that imbalance.

Partially supportedHigh confidence

The claim involves two mechanistic components: (1) high methionine intake depleting glycine via the transsulfuration pathway, and (2) glycine supplementation correcting this imbalance on high-protein…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Mechanism discussion

Glycine is also the most abundant amino acid in collagen, comprising about 33% of its total content. For skin aging, joint health, and gut mucosal integrity, maintaining adequate glycine intake to support collagen synthesis is relevant.

Extracted claim

Glycine is the most abundant amino acid in collagen, comprising about 33% of its total content, and is relevant for skin aging, joint health, and gut mucosal integrity.

Partially supportedHigh confidence

The claim that glycine is the most abundant amino acid in collagen (~33%) is a well-established biochemical fact, and the provided literature (PMIDs 37510995, 28337245) reviews glycine's broad biologi…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Mechanism discussion

glycine is also a precursor to creatine synthesis in the body and is critical for collagen formation. So there are potential secondary benefits beyond sleep.

Extracted claim

Glycine is a precursor to creatine synthesis in the body and is critical for collagen formation, providing potential secondary benefits beyond sleep.

Partially supportedHigh confidence

The claim that glycine is a precursor to creatine synthesis is supported mechanistically by the creatine review (PMID: 17430086), which covers endogenous creatine biosynthesis pathways involving glyci…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Mechanism discussion

methionine — the amino acid found abundantly in meat — requires glycine for its metabolism. People who eat a lot of animal protein may have relatively higher glycine needs, and supplementing may help balance that ratio.

Extracted claim

Methionine, found abundantly in meat, requires glycine for its metabolism, meaning people who eat a lot of animal protein may have relatively higher glycine needs and supplementing may help balance that ratio.

Insufficient evidence to assessHigh confidence

The expert's claim involves a specific mechanistic relationship between methionine metabolism and glycine requirements in high meat consumers. While PMID 28337245 (review on glycine's multifarious ben…

Mark Hyman
Mark Hyman
Cleveland Clinic Center for Functional Medicine
Mechanism discussion

properly detoxify like glycin conation glonation so forth and these are these are basic biochemical steps that require the right amount of amino acids and protein

Extracted claim

Glycine is one of the amino acids required for proper detoxification pathways in the body.

Supported by researchMedium confidence

Multiple reviews in the provided literature support glycine's role in detoxification pathways. The review on glycine's multifarious benefits (PMID: 28337245) describes glycine as a precursor in biosyn…

Mark Hyman
Mark Hyman
Cleveland Clinic Center for Functional Medicine
Mechanism discussion

the beautiful thing about um protein is it's full of other good things like B vitamins amino acids glycine torine cysteine methine all critical

Extracted claim

Protein foods contain glycine along with other amino acids that are critical for health.

Partially supportedHigh confidence

The claim that protein foods contain glycine along with other amino acids critical for health is broadly supported by mechanistic reviews in the provided literature. The glycine review (PMID: 28337245…

Mark Hyman
Mark Hyman
Cleveland Clinic Center for Functional Medicine
Mechanism discussion

properly detoxify like glycin conation glonation so forth and these are these are basic biochemical steps that require the right amount of amino acids and protein

Extracted claim

Glycine is one of the amino acids required for proper detoxification pathways in the body.

Supported by researchMedium confidence

Multiple reviews in the provided literature support glycine's role in detoxification pathways. The review on glycine's multifarious benefits (PMID: 28337245) and the systematic review on glycine admin…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Personal anecdote

The dose that I take and that was used in that study is 3 grams about 30 minutes before bed.

Extracted claim

Huberman personally takes 3 grams of glycine approximately 30 minutes before bed, the same dose used in the Bannai and Kawai study.

3 grams30 minutes before bed📍 sleep optimization
Insufficient evidence to assessHigh confidence

The expert's claim is a personal anecdote about his own supplement regimen (3g glycine, 30 minutes before bed), referencing the Bannai and Kawai study. None of the 10 provided research abstracts corre…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Personal anecdote

The dose that I take and that was used in that study is 3 grams about 30 minutes before bed.

Extracted claim

Huberman personally takes 3 grams of glycine approximately 30 minutes before bed, the same dose used in the Bannai and Kawai study.

3 grams30 minutes before bed📍 sleep optimization
Insufficient evidence to assessHigh confidence

The expert's claim is a personal anecdote about his own supplement regimen (3g glycine ~30 minutes before bed) and references the Bannai and Kawai study. However, the Bannai and Kawai study is not inc…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Personal anecdote

The dose that I take and that was used in that study is 3 grams about 30 minutes before bed.

Extracted claim

Huberman personally takes 3 grams of glycine approximately 30 minutes before bed, the same dose used in the Bannai and Kawai study.

3 grams30 minutes before bed📍 sleep optimization
Insufficient evidence to assessHigh confidence

The expert's claim is a personal anecdote about his own supplement routine (3g glycine ~30 minutes before bed, referencing the Bannai and Kawai study). The published research provided includes reviews…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Personal anecdote

The dose that I take and that was used in that study is 3 grams about 30 minutes before bed.

Extracted claim

Huberman personally takes 3 grams of glycine approximately 30 minutes before bed, the same dose used in the Bannai and Kawai study.

3 grams30 minutes before bed📍 sleep optimization
Insufficient evidence to assessHigh confidence

The expert's claim is a personal anecdote about his own supplement regimen (3g glycine ~30 minutes before bed) and references a specific study by Bannai and Kawai. None of the 10 provided research abs…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Personal anecdote

The dose that I take and that was used in that study is 3 grams about 30 minutes before bed.

Extracted claim

Huberman personally takes 3 grams of glycine approximately 30 minutes before bed, the same dose used in the Bannai and Kawai study.

3 grams30 minutes before bed📍 sleep optimization
Insufficient evidence to assessHigh confidence

The expert's claim is a personal anecdote about his own supplement routine (3g glycine ~30 minutes before bed) and a reference to the Bannai and Kawai study. None of the 10 provided research sources i…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Personal anecdote

The dose that I take and that was used in that study is 3 grams about 30 minutes before bed.

Extracted claim

Huberman personally takes 3 grams of glycine approximately 30 minutes before bed, the same dose used in the Bannai and Kawai study.

3 grams30 minutes before bed📍 sleep optimization
Insufficient evidence to assessHigh confidence

Huberman's claim is a personal anecdote about his own supplement routine (3g glycine before bed, referencing the Bannai and Kawai study). The published research provided does not include the Bannai an…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Personal anecdote

The dose that I take and that was used in that study is 3 grams about 30 minutes before bed.

Extracted claim

Huberman personally takes 3 grams of glycine approximately 30 minutes before bed, the same dose used in the Bannai and Kawai study.

3 grams30 minutes before bed📍 sleep optimization
Insufficient evidence to assessHigh confidence

The expert's claim is a personal anecdote about his own supplement regimen (3g glycine ~30 min before bed, referencing the Bannai and Kawai study). None of the 10 provided research abstracts correspon…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Caution / warning

At doses up to 9 grams in acute studies, there are essentially no adverse effects.

Extracted claim

At doses up to 9 grams in acute studies, glycine produces essentially no adverse effects.

9 grams📍 Upper bound tested in acute studies with no adverse effects observed
Insufficient evidence to assessHigh confidence

None of the 10 listed studies directly evaluate the safety or adverse effect profile of glycine at doses up to 9 grams in acute human studies. The glycine-related papers (PMIDs 37510995, 28337245) are…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Caution / warning

At doses up to 9 grams in acute studies, there are essentially no adverse effects.

Extracted claim

At doses up to 9 grams in acute studies, glycine produces essentially no adverse effects.

9 grams📍 Upper bound tested in acute studies with no adverse effects observed
Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly address the safety or tolerability of acute glycine supplementation at doses up to 9 grams. While several studies (e.g., PMID 35975308 on GlyNAC and PMID 28337…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Caution / warning

At doses up to 9 grams in acute studies, there are essentially no adverse effects.

Extracted claim

At doses up to 9 grams in acute studies, glycine produces essentially no adverse effects.

9 grams📍 Upper bound tested in acute studies with no adverse effects observed
Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly evaluate the safety or adverse effect profile of acute glycine supplementation at doses up to 9 grams in human adults. While PMID 37851316 is a systematic revi…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Caution / warning

At doses up to 9 grams in acute studies, there are essentially no adverse effects.

Extracted claim

At doses up to 9 grams in acute studies, glycine produces essentially no adverse effects.

9 grams📍 Upper bound tested in acute studies with no adverse effects observed
Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly investigate the safety or tolerability of acute glycine supplementation at doses up to 9 grams in humans. While several papers reference glycine (e.g., PMIDs 3…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Caution / warning

At doses up to 9 grams in acute studies, there are essentially no adverse effects.

Extracted claim

At doses up to 9 grams in acute studies, glycine produces essentially no adverse effects.

9 grams📍 Upper bound tested in acute studies with no adverse effects observed
Insufficient evidence to assessHigh confidence

None of the 10 listed studies directly examine the safety or adverse effect profile of glycine at doses up to 9 grams in acute studies. While two reviews (PMIDs 37510995 and 28337245) discuss glycine'…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Caution / warning

At doses up to 9 grams in acute studies, there are essentially no adverse effects.

Extracted claim

At doses up to 9 grams in acute studies, glycine produces essentially no adverse effects.

9 grams📍 Upper bound tested in acute studies with no adverse effects observed
Insufficient evidence to assessHigh confidence

While PMID 37851316 (a systematic review on glycine administration in human adults) is the most relevant study in this list and could potentially address safety at acute doses, no key findings, popula…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Caution / warning

At doses up to 9 grams in acute studies, there are essentially no adverse effects.

Extracted claim

At doses up to 9 grams in acute studies, glycine produces essentially no adverse effects.

9 grams📍 Upper bound tested in acute studies with no adverse effects observed
Insufficient evidence to assessHigh confidence

None of the provided studies directly evaluate the safety or tolerability profile of glycine at doses up to 9 grams in acute human studies. While the GlyNAC RCT (PMID: 35975308) and glycine review art…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Caution / warning

At doses up to 9 grams in acute studies, there are essentially no adverse effects.

Extracted claim

At doses up to 9 grams in acute studies, glycine produces essentially no adverse effects.

9 grams📍 Upper bound tested in acute studies with no adverse effects observed
Insufficient evidence to assessHigh confidence

The provided research corpus does not contain studies that directly assess the safety or adverse effect profile of glycine at acute doses up to 9 grams in humans. PMID 37851316 (a systematic review on…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Passing mention

Glycine has a sweet taste that makes it easy to dissolve in water.

Extracted claim

Glycine has a sweet taste that makes it easy to dissolve in water.

dissolved in water
Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly address glycine's taste properties or its solubility in water. The claim that glycine has a sweet taste and dissolves easily in water is a well-known physicoch…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Passing mention

Glycine has a sweet taste that makes it easy to dissolve in water.

Extracted claim

Glycine has a sweet taste that makes it easy to dissolve in water.

dissolved in water
Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly address glycine's taste properties or its solubility characteristics in water. The claim that glycine has a sweet taste and dissolves easily in water is a well…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Passing mention

Glycine has a sweet taste that makes it easy to dissolve in water.

Extracted claim

Glycine has a sweet taste that makes it easy to dissolve in water.

dissolved in water
Insufficient evidence to assessHigh confidence

None of the 10 published studies listed address the taste or solubility characteristics of glycine. The claim that glycine has a sweet taste and dissolves easily in water is a basic physicochemical an…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Passing mention

Glycine has a sweet taste that makes it easy to dissolve in water.

Extracted claim

Glycine has a sweet taste that makes it easy to dissolve in water.

dissolved in water
Insufficient evidence to assessHigh confidence

None of the 20 published research abstracts listed address the sensory properties of glycine, such as its taste or solubility in water. While several studies (PMIDs 37510995, 28337245, 37851316, 35975…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Passing mention

Glycine has a sweet taste that makes it easy to dissolve in water.

Extracted claim

Glycine has a sweet taste that makes it easy to dissolve in water.

dissolved in water
Insufficient evidence to assessHigh confidence

The expert's claim that glycine has a sweet taste that makes it easy to dissolve in water is a basic physicochemical and organoleptic fact about the amino acid, not a health or clinical claim. None of…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Passing mention

Glycine has a sweet taste that makes it easy to dissolve in water.

Extracted claim

Glycine has a sweet taste that makes it easy to dissolve in water.

dissolved in water
Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly address the taste or solubility characteristics of glycine. The claim that glycine has a sweet taste and dissolves easily in water is a well-established physic…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Passing mention

Glycine has a sweet taste that makes it easy to dissolve in water.

Extracted claim

Glycine has a sweet taste that makes it easy to dissolve in water.

dissolved in water
Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly address glycine's taste properties or its solubility characteristics in water. The claim that glycine has a sweet taste and dissolves easily in water is a basi…

Rhonda Patrick
Rhonda Patrick
FoundMyFitness
Passing mention

Glycine has a sweet taste that makes it easy to dissolve in water.

Extracted claim

Glycine has a sweet taste that makes it easy to dissolve in water.

dissolved in water
Insufficient evidence to assessHigh confidence

None of the 10 provided studies directly address the taste or solubility properties of glycine. The claim that glycine has a sweet taste and dissolves easily in water is a well-established physicochem…