Fish Oil / Omega-3 vs Glycine
Both are commonly discussed for muscle & recovery. Fish Oil / Omega-3 and Glycine both have moderate evidence — Fish Oil / Omega-3 edges ahead on research volume (20 vs 20 studies referenced).
Evidence last reviewed May 2026
Fish Oil / Omega-3
Essential Fatty Acid
Glycine
Amino Acid
Evidence
🟡Moderate Evidence
🟡Moderate Evidence
Research says
Partially supported
Research agrees
Expert mentions
181
4 recommend
176
3 recommend
Studies
20
referenced
20
referenced
Study dose
1000–4000mg
Studies across the reviewed literature examined doses ranging from approximately 1,000 mg to 4,000 mg of combined EPA+DHA per day; expert commentary (Huberman) highlights doses above 1 g EPA/day for mood effects and 2–4 g/day for triglyceride reduction, though optimal doses vary by condition and individual.
3000–15000mg
Sleep studies primarily used 3g (3000mg); the GlyNAC RCT and broader therapeutic reviews reference ranges up to 9–15g daily depending on the health outcome studied. Higher doses have been used in metabolic and aging contexts without notable adverse effects reported.
Best timing
MorningWith food
EveningEmpty stomach
Who recommends
Caution
Generally safe
Generally safe
Fish Oil / Omega-3
Key findings
- ·Multiple strong-quality meta-analyses and systematic reviews suggest fish oil supplementation may improve blood lipid profiles (particularly triglycerides) in people with hyperlipidemia, and may reduce arterial stiffness based on randomized controlled trial data.
- ·Omega-3 supplementation has been investigated for PCOS, with systematic reviews and umbrella reviews of meta-analyses examining effects on metabolic and endocrine outcomes, though the strength and consistency of benefit varies across endpoints.
- ·A Mediterranean-style dietary intervention supplemented with fish oil showed promising signals for mental health improvement in people with depression, though this was a single moderate-quality RCT and conclusions should be drawn cautiously.
Evidence gaps
- ·Most individual studies in this set do not report specific population characteristics or sample sizes in the available metadata, making it difficult to determine which populations benefit most and whether findings generalize broadly.
- ·The majority of expert claims assessed (135 out of 169) were rated as having insufficient evidence, suggesting that many specific claims made about fish oil — including highly specific therapeutic applications — outpace what the current research can confidently support.
Glycine
Key findings
- ·A randomized clinical trial of GlyNAC (glycine + N-acetylcysteine) in older adults found improvements in glutathione deficiency, oxidative stress, mitochondrial dysfunction, inflammation, and physical function, supporting glycine's role as a key substrate for glutathione synthesis.
- ·Glycine is a well-established biochemical precursor to glutathione, creatine, and collagen — three molecules with broad relevance to aging, muscle function, and tissue integrity.
- ·Glycine may be conditionally essential in older adults and under high physiological demand, as endogenous synthesis appears insufficient to meet total-body requirements in these contexts.
Evidence gaps
- ·Most clinical evidence for glycine uses combination products (e.g., GlyNAC, gelatin + vitamin C), making it impossible to determine how much of the observed benefit is attributable to glycine alone versus co-ingredients.
- ·Long-term supplementation trials in diverse human populations are lacking; existing studies are largely short-term and focused on older adults or athletes, leaving gaps for other demographics including those with chronic disease.