Abstraction Health

Tongkat Ali — Expert Claims

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

Expert Consensus

Research agrees
1/5
Experts mention
1
Recommend
1
Flag caution
Andrew Huberman
Andrew Huberman Recommends Caution
Research agrees64 claims200milligrams or 400milligramsstandardized extracthigh-potency standardized extract

Dose divergence: Experts recommend different amounts (200milligrams, 400milligrams). 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:Andrew Huberman

64 expert mentions

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

men with documented low testosterone — either from hypogonadism, chronic stress, or aging — seem to get the most benefit. If your testosterone is already in the high-normal range, Tongkat Ali is unlikely to push it higher.

Extracted claim

Men with documented low testosterone — from hypogonadism, chronic stress, or aging — appear to benefit most from Tongkat Ali; those already in the high-normal testosterone range are unlikely to see further increases.

Partially supportedHigh confidence

The RCT (PMID: 33541567) specifically studied men with androgen deficiency of aging males (ADAM) — a population with documented low testosterone — and examined Tongkat Ali's effects on erectile functi…

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

look for products standardized to eurycomanone content

Extracted claim

Huberman recommends looking for tongkat ali products standardized to eurycomanone content.

standardized extract📍 standardized to eurycomanone content
Insufficient evidence to assessHigh confidence

None of the four provided studies contain extractable key findings that directly address whether eurycomanone standardization is a meaningful quality marker for tongkat ali products. While the review…

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

look for products standardized to eurycomanone content

Extracted claim

Huberman recommends looking for tongkat ali products standardized to eurycomanone content.

standardized extract📍 standardized to eurycomanone content
Insufficient evidence to assessHigh confidence

The four studies provided (two systematic reviews, one moderate-quality RCT on Eurycoma longifolia with concurrent training in aging males, and one narrative review on traditional uses and pharmacolog…

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

look for products standardized to eurycomanone content

Extracted claim

Huberman recommends looking for tongkat ali products standardized to eurycomanone content.

standardized extract📍 standardized to eurycomanone content
Insufficient evidence to assessHigh confidence

None of the four provided studies contain key findings, populations, or limitations data that would allow a direct assessment of whether eurycomanone standardization is a validated or recommended qual…

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

look for products standardized to eurycomanone content

Extracted claim

Huberman recommends looking for tongkat ali products standardized to eurycomanone content.

standardized extract📍 standardized to eurycomanone content
Insufficient evidence to assessHigh confidence

None of the four studies provided directly evaluate or validate eurycomanone standardization as a marker of product quality or efficacy for tongkat ali. The review (PMID: 26978330) discusses the chemi…

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

men with documented low testosterone — either from hypogonadism, chronic stress, or aging — seem to get the most benefit. If your testosterone is already in the high-normal range, Tongkat Ali is unlikely to push it higher.

Extracted claim

Men with documented low testosterone — from hypogonadism, chronic stress, or aging — benefit most from Tongkat Ali; those with already high-normal testosterone are unlikely to see further increases.

Partially supportedHigh confidence

The RCT (PMID: 33541567) specifically studied Eurycoma longifolia in men with androgen deficiency of aging males (ADAM), a population with documented low testosterone, lending some direct support to H…

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

look for products standardized to eurycomanone content

Extracted claim

Huberman recommends looking for tongkat ali products standardized to eurycomanone content.

standardized extract📍 standardized to eurycomanone content
Insufficient evidence to assessHigh confidence

None of the four provided studies contain key findings, population data, or limitations details that would allow a direct evaluation of Huberman's recommendation to seek tongkat ali products standardi…

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

Another study in stressed individuals showed normalization of testosterone and cortisol levels that had been depressed by stress.

Extracted claim

A study in stressed individuals showed Tongkat Ali normalized testosterone and cortisol levels that had been depressed by stress.

Insufficient evidence to assessHigh confidence

None of the four studies provided directly examine the specific claim that Tongkat Ali normalized testosterone and cortisol levels in stressed individuals. The review (PMID: 26978330) covers general p…

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

Some studies show increases in both total and free testosterone; others show primarily free testosterone increases.

Extracted claim

Some studies show tongkat ali increases both total and free testosterone; others show primarily free testosterone increases.

Insufficient evidence to assessHigh confidence

While the provided research list includes relevant study types (an RCT, systematic reviews, and a review on Eurycoma longifolia), none of the entries include extractable key findings, populations, or…

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

men with documented low testosterone — either from hypogonadism, chronic stress, or aging — seem to get the most benefit. If your testosterone is already in the high-normal range, Tongkat Ali is unlikely to push it higher.

Extracted claim

Men with documented low testosterone — from hypogonadism, chronic stress, or aging — appear to benefit most from tongkat ali; those with already high-normal testosterone are unlikely to see further increases.

Insufficient evidence to assessHigh confidence

While one RCT (PMID: 33541567) specifically examined tongkat ali in androgen-deficient aging males (ADAM), suggesting some research focus on low-testosterone populations, the key findings and sample s…

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

A 2012 study showed that 200 milligrams per day of a standardized extract increased free testosterone by about 37% and significantly improved scores on a standardized erectile dysfunction questionnaire in men with low testosterone.

Extracted claim

A 2012 study showed that 200 milligrams per day of a standardized tongkat ali extract increased free testosterone by about 37% and significantly improved scores on a standardized erectile dysfunction questionnaire in men with low testosterone.

200 milligramsstandardized extractper day📍 dose used in a 2012 clinical study in men with low testosterone
Insufficient evidence to assessHigh confidence

The expert references a specific 2012 RCT showing 37% free testosterone increase and improved erectile dysfunction scores with 200mg/day standardized tongkat ali extract in men with low testosterone.…

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

Another study in stressed individuals showed normalization of testosterone and cortisol levels that had been depressed by stress.

Extracted claim

A study in stressed individuals showed normalization of testosterone and cortisol levels that had been depressed by stress.

Insufficient evidence to assessHigh confidence

The expert's claim specifically references normalization of testosterone and cortisol levels in stressed individuals, which appears to describe a particular study on Tongkat Ali (Eurycoma longifolia).…

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

Some studies show increases in both total and free testosterone; others show primarily free testosterone increases.

Extracted claim

Some studies show tongkat ali increases both total and free testosterone; others show primarily free testosterone increases.

Insufficient evidence to assessHigh confidence

While the provided research list includes relevant study types (one RCT, one systematic review, and review articles on Eurycoma longifolia), none of the records include extractable key findings, popul…

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

men with documented low testosterone — either from hypogonadism, chronic stress, or aging — seem to get the most benefit. If your testosterone is already in the high-normal range, Tongkat Ali is unlikely to push it higher.

Extracted claim

Men with documented low testosterone — from hypogonadism, chronic stress, or aging — appear to benefit most from tongkat ali; those with already high-normal testosterone are unlikely to see further increases.

Insufficient evidence to assessHigh confidence

The available research includes one RCT (PMID: 33541567) specifically studying tongkat ali in androgen-deficient aging males (ADAM), which is relevant to Huberman's claim about low-testosterone popula…

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

men with documented low testosterone — either from hypogonadism, chronic stress, or aging — seem to get the most benefit. If your testosterone is already in the high-normal range, Tongkat Ali is unlikely to push it higher.

Extracted claim

Men with documented low testosterone — from hypogonadism, chronic stress, or aging — appear to benefit most from tongkat ali; those with already high-normal testosterone are unlikely to see further increases.

Insufficient evidence to assessHigh confidence

The available studies include one moderate-quality RCT (PMID: 33541567) specifically examining tongkat ali in androgen-deficient aging males (ADAM), which is the most relevant population to Huberman's…

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

Some studies show increases in both total and free testosterone; others show primarily free testosterone increases.

Extracted claim

Some studies show tongkat ali increases both total and free testosterone; others show primarily free testosterone increases.

Insufficient evidence to assessHigh confidence

While the provided research list includes relevant study types (one RCT, two systematic reviews, and one traditional review) that could in principle address testosterone outcomes with tongkat ali, non…

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

A 2012 study showed that 200 milligrams per day of a standardized extract increased free testosterone by about 37% and significantly improved scores on a standardized erectile dysfunction questionnaire in men with low testosterone.

Extracted claim

A 2012 study showed that 200 milligrams per day of a standardized tongkat ali extract increased free testosterone by about 37% and significantly improved scores on a standardized erectile dysfunction questionnaire in men with low testosterone.

200 milligramsstandardized extractper day📍 dose used in a 2012 clinical study in men with low testosterone
Insufficient evidence to assessHigh confidence

The provided research abstracts contain no extractable key findings, populations, or limitations data, making it impossible to directly verify or refute Huberman's specific claim about a 2012 study sh…

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

men with documented low testosterone — either from hypogonadism, chronic stress, or aging — seem to get the most benefit. If your testosterone is already in the high-normal range, Tongkat Ali is unlikely to push it higher.

Extracted claim

Men with documented low testosterone — from hypogonadism, chronic stress, or aging — appear to benefit most from tongkat ali; those with already high-normal testosterone are unlikely to see further increases.

Insufficient evidence to assessHigh confidence

The available research includes one relevant RCT (PMID: 33541567) examining Tongkat Ali in androgen-deficient aging males (ADAM), which is the population most aligned with Huberman's claim, but the ke…

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

Another study in stressed individuals showed normalization of testosterone and cortisol levels that had been depressed by stress.

Extracted claim

A study in stressed individuals showed normalization of testosterone and cortisol levels that had been depressed by stress.

Insufficient evidence to assessHigh confidence

The claim references a specific study showing normalization of testosterone and cortisol levels in stressed individuals, but none of the four provided research entries contain key findings, population…

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

A 2012 study showed that 200 milligrams per day of a standardized extract increased free testosterone by about 37% and significantly improved scores on a standardized erectile dysfunction questionnaire in men with low testosterone.

Extracted claim

A 2012 study showed that 200 milligrams per day of a standardized tongkat ali extract increased free testosterone by about 37% and significantly improved scores on a standardized erectile dysfunction questionnaire in men with low testosterone.

200 milligramsstandardized extractper day📍 dose used in a 2012 clinical study in men with low testosterone
Insufficient evidence to assessHigh confidence

The provided research summaries lack key fields (key findings, population details, limitations) needed to directly verify or refute Huberman's specific claim about a 2012 study showing 37% free testos…

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

Another study in stressed individuals showed normalization of testosterone and cortisol levels that had been depressed by stress.

Extracted claim

A study in stressed individuals showed normalization of testosterone and cortisol levels that had been depressed by stress.

Insufficient evidence to assessHigh confidence

The expert's claim specifically references a study in stressed individuals showing normalization of testosterone and cortisol levels, which implies a specific human trial (likely the Hamzah & Yusof 20…

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

Some studies show increases in both total and free testosterone; others show primarily free testosterone increases.

Extracted claim

Some studies show tongkat ali increases both total and free testosterone; others show primarily free testosterone increases.

Insufficient evidence to assessHigh confidence

While four studies are cited in the evidence base (including one RCT examining tongkat ali over 6 months in ADAM patients, two systematic reviews, and one traditional medicine review), none of the pro…

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

Another study in stressed individuals showed normalization of testosterone and cortisol levels that had been depressed by stress.

Extracted claim

A study in stressed individuals showed normalization of testosterone and cortisol levels that had been depressed by stress.

Insufficient evidence to assessHigh confidence

The provided research corpus does not contain the specific study Huberman references — one involving stressed individuals with depressed testosterone and cortisol that were normalized by supplementati…

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

A 2012 study showed that 200 milligrams per day of a standardized extract increased free testosterone by about 37% and significantly improved scores on a standardized erectile dysfunction questionnaire in men with low testosterone.

Extracted claim

A 2012 study showed that 200 milligrams per day of a standardized tongkat ali extract increased free testosterone by about 37% and significantly improved scores on a standardized erectile dysfunction questionnaire in men with low testosterone.

200 milligramsstandardized extractper day📍 dose used in a 2012 clinical study in men with low testosterone
Insufficient evidence to assessHigh confidence

The provided research abstracts contain no extractable key findings, populations, or limitations, making it impossible to directly verify or contradict Huberman's specific claim about a 2012 study sho…

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

Another study in stressed individuals showed normalization of testosterone and cortisol levels that had been depressed by stress.

Extracted claim

A study in stressed individuals showed normalization of testosterone and cortisol levels that had been depressed by stress.

Insufficient evidence to assessHigh confidence

None of the four provided studies directly examine the effect of Tongkat Ali on testosterone and cortisol normalization in stressed individuals, which is the specific claim being made. The RCT (PMID:…

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

A 2012 study showed that 200 milligrams per day of a standardized extract increased free testosterone by about 37% and significantly improved scores on a standardized erectile dysfunction questionnaire in men with low testosterone.

Extracted claim

A 2012 study showed that 200 milligrams per day of a standardized tongkat ali extract increased free testosterone by about 37% and significantly improved scores on a standardized erectile dysfunction questionnaire in men with low testosterone.

200 milligramsstandardized extractper day📍 dose used in a 2012 clinical study in men with low testosterone
Insufficient evidence to assessHigh confidence

None of the four provided studies is the specific 2012 RCT Huberman references. The closest relevant study is PMID 33541567, a 6-month double-blind RCT on Tongkat Ali and erectile function in men with…

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

Some studies show increases in both total and free testosterone; others show primarily free testosterone increases.

Extracted claim

Some studies show tongkat ali increases both total and free testosterone; others show primarily free testosterone increases.

Partially supportedHigh confidence

The RCT (PMID: 33541567) provides the most directly relevant evidence, being a 6-month double-blind placebo-controlled trial examining Eurycoma longifolia's effects on testosterone levels in aging mal…

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

men with documented low testosterone — either from hypogonadism, chronic stress, or aging — seem to get the most benefit. If your testosterone is already in the high-normal range, Tongkat Ali is unlikely to push it higher.

Extracted claim

Men with documented low testosterone — from hypogonadism, chronic stress, or aging — appear to benefit most from tongkat ali; those with already high-normal testosterone are unlikely to see further increases.

Partially supportedHigh confidence

The RCT (PMID: 33541567) specifically studied men with androgen deficiency of aging males (ADAM) — a population with documented low testosterone — and examined whether Eurycoma longifolia improved ere…

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

A 2012 study showed that 200 milligrams per day of a standardized extract increased free testosterone by about 37% and significantly improved scores on a standardized erectile dysfunction questionnaire in men with low testosterone.

Extracted claim

A 2012 study found that 200 mg/day of a standardized Tongkat Ali extract increased free testosterone by about 37% and significantly improved erectile dysfunction questionnaire scores in men with low testosterone.

200 milligramsstandardized extractper day📍 dose used in the cited 2012 study
Insufficient evidence to assessHigh confidence

The expert references a specific 2012 RCT examining 200 mg/day of standardized Tongkat Ali extract with a 37% increase in free testosterone, but none of the four studies provided in the evidence list…

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

It's a root extract from a Southeast Asian shrub that has been used in traditional medicine for centuries, primarily for male vitality.

Extracted claim

Tongkat ali is a root extract from a Southeast Asian shrub that has been used in traditional medicine for centuries, primarily for male vitality.

Partially supportedHigh confidence

The claim that tongkat ali is a root extract from a Southeast Asian shrub used in traditional medicine for male vitality is broadly consistent with the literature. The review (PMID: 26978330) on Euryc…

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

Tongkat Ali appears to lower cortisol and improve subjective stress scores, which may be part of why it improves testosterone given the well-known inverse relationship between cortisol and testosterone.

Extracted claim

Tongkat ali appears to lower cortisol and improve subjective stress scores, which may partly explain its testosterone-boosting effects given the inverse relationship between cortisol and testosterone.

Insufficient evidence to assessHigh confidence

The four provided studies (two systematic reviews, one RCT, one narrative review) do not contain extractable key findings, populations, or limitations in the data supplied, making it impossible to dir…

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

Tongkat Ali appears to lower cortisol and improve subjective stress scores, which may be part of why it improves testosterone given the well-known inverse relationship between cortisol and testosterone.

Extracted claim

Tongkat ali appears to lower cortisol and improve subjective stress scores, which may partly explain its testosterone-boosting effects given the inverse relationship between cortisol and testosterone.

Insufficient evidence to assessHigh confidence

The provided research abstracts contain no key findings, populations, or limitations data, making it impossible to directly assess Huberman's claim that tongkat ali lowers cortisol and improves subjec…

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

Tongkat Ali appears to lower cortisol and improve subjective stress scores, which may be part of why it improves testosterone given the well-known inverse relationship between cortisol and testosterone.

Extracted claim

Tongkat ali appears to lower cortisol and improve subjective stress scores, which may partly explain its testosterone-boosting effects given the inverse relationship between cortisol and testosterone.

Insufficient evidence to assessHigh confidence

The provided research abstracts contain no extractable key findings, populations, or limitations, making it impossible to directly evaluate Huberman's claim that tongkat ali lowers cortisol, improves…

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

It's a root extract from a Southeast Asian shrub that has been used in traditional medicine for centuries, primarily for male vitality.

Extracted claim

Tongkat ali is a root extract from a Southeast Asian shrub that has been used in traditional medicine for centuries, primarily for male vitality.

Partially supportedHigh confidence

The expert's claim that Tongkat Ali (Eurycoma longifolia) is a Southeast Asian root extract used in traditional medicine for male vitality is broadly consistent with the literature. The review article…

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

The mechanism of action for testosterone support appears to involve reducing SHBG — sex hormone binding globulin. SHBG binds to testosterone in the blood, and only the unbound fraction — free testosterone — is biologically active. If Tongkat Ali reduces SHBG, it would increase free testosterone without necessarily changing total testosterone.

Extracted claim

The mechanism by which tongkat ali supports testosterone appears to involve reducing SHBG, which increases free testosterone without necessarily changing total testosterone.

Insufficient evidence to assessHigh confidence

The four studies provided (two systematic reviews, one RCT, one review) do not contain extractable key findings, populations, or limitations in the data supplied, making it impossible to directly eval…

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

The mechanism of action for testosterone support appears to involve reducing SHBG — sex hormone binding globulin. SHBG binds to testosterone in the blood, and only the unbound fraction — free testosterone — is biologically active. If Tongkat Ali reduces SHBG, it would increase free testosterone without necessarily changing total testosterone.

Extracted claim

The mechanism by which tongkat ali supports testosterone appears to involve reducing SHBG, which increases free testosterone without necessarily changing total testosterone.

Insufficient evidence to assessHigh confidence

The four studies provided (a systematic review [PMID 36013514], a narrative review [PMID 26978330], an erectile dysfunction supplement analysis [PMID 31036522], and a 6-month RCT in ADAM patients [PMI…

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

The mechanism of action for testosterone support appears to involve reducing SHBG — sex hormone binding globulin. SHBG binds to testosterone in the blood, and only the unbound fraction — free testosterone — is biologically active. If Tongkat Ali reduces SHBG, it would increase free testosterone without necessarily changing total testosterone.

Extracted claim

The mechanism by which tongkat ali supports testosterone appears to involve reducing SHBG, which increases free testosterone without necessarily changing total testosterone.

Insufficient evidence to assessHigh confidence

The four studies provided (two systematic reviews, one RCT, one narrative review) contain no extractable key findings in the data supplied, making it impossible to directly evaluate Huberman's specifi…

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

The mechanism of action for testosterone support appears to involve reducing SHBG — sex hormone binding globulin. SHBG binds to testosterone in the blood, and only the unbound fraction — free testosterone — is biologically active. If Tongkat Ali reduces SHBG, it would increase free testosterone without necessarily changing total testosterone.

Extracted claim

The mechanism by which tongkat ali supports testosterone appears to involve reducing SHBG, which increases free testosterone without necessarily changing total testosterone.

Insufficient evidence to assessHigh confidence

The four studies provided (two systematic reviews, one RCT, and one narrative review) do not contain extractable key findings in the data supplied, making it impossible to directly evaluate Huberman's…

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

It's a root extract from a Southeast Asian shrub that has been used in traditional medicine for centuries, primarily for male vitality.

Extracted claim

Tongkat ali is a root extract from a Southeast Asian shrub that has been used in traditional medicine for centuries, primarily for male vitality.

Partially supportedHigh confidence

The expert's claim that tongkat ali (Eurycoma longifolia) is a Southeast Asian root extract with centuries of traditional use for male vitality is broadly consistent with the available literature. The…

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

It's a root extract from a Southeast Asian shrub that has been used in traditional medicine for centuries, primarily for male vitality.

Extracted claim

Tongkat ali is a root extract from a Southeast Asian shrub that has been used in traditional medicine for centuries, primarily for male vitality.

Partially supportedHigh confidence

The claim that Tongkat ali (Eurycoma longifolia) is a Southeast Asian root extract used in traditional medicine for male vitality is broadly consistent with the available literature. The PMID 26978330…

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

The mechanism of action for testosterone support appears to involve reducing SHBG — sex hormone binding globulin. SHBG binds to testosterone in the blood, and only the unbound fraction — free testosterone — is biologically active. If Tongkat Ali reduces SHBG, it would increase free testosterone without necessarily changing total testosterone.

Extracted claim

Tongkat Ali's mechanism for testosterone support appears to involve reducing SHBG, which increases the biologically active free testosterone fraction.

Insufficient evidence to assessHigh confidence

None of the four provided studies directly test or confirm the specific mechanistic claim that Tongkat Ali reduces SHBG (Sex Hormone-Binding Globulin) to increase free testosterone. The RCT (PMID: 335…

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

Tongkat Ali appears to lower cortisol and improve subjective stress scores, which may be part of why it improves testosterone given the well-known inverse relationship between cortisol and testosterone.

Extracted claim

Tongkat Ali appears to lower cortisol and improve subjective stress scores, which may contribute to its testosterone-boosting effects given the inverse relationship between cortisol and testosterone.

Insufficient evidence to assessHigh confidence

None of the four provided studies directly measure or report cortisol levels or subjective stress scores in relation to Tongkat Ali supplementation. The RCT (PMID: 33541567) examined erectile function…

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

Tongkat Ali appears to lower cortisol and improve subjective stress scores, which may be part of why it improves testosterone given the well-known inverse relationship between cortisol and testosterone.

Extracted claim

Tongkat ali appears to lower cortisol and improve subjective stress scores, which may partly explain its testosterone-boosting effects given the inverse relationship between cortisol and testosterone.

Insufficient evidence to assessHigh confidence

The four studies retrieved (two systematic reviews, one RCT, one narrative review) do not provide extractable key findings, populations, or limitations in the data provided, making it impossible to di…

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

It's a root extract from a Southeast Asian shrub that has been used in traditional medicine for centuries, primarily for male vitality.

Extracted claim

Tongkat ali is a root extract from a Southeast Asian shrub that has been used in traditional medicine for centuries, primarily for male vitality.

Supported by researchHigh confidence

The expert's claim that tongkat ali is a root extract from a Southeast Asian shrub used in traditional medicine for male vitality is directly supported by the review (PMID: 26978330), which identifies…

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

The mechanism of action for testosterone support appears to involve reducing SHBG — sex hormone binding globulin. SHBG binds to testosterone in the blood, and only the unbound fraction — free testosterone — is biologically active. If Tongkat Ali reduces SHBG, it would increase free testosterone without necessarily changing total testosterone.

Extracted claim

The mechanism by which tongkat ali supports testosterone appears to involve reducing SHBG, which increases free testosterone without necessarily changing total testosterone.

Insufficient evidence to assessHigh confidence

None of the four listed studies directly examine or confirm the specific mechanism Huberman describes — that tongkat ali reduces SHBG to increase free testosterone without necessarily changing total t…

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

Tongkat Ali appears to lower cortisol and improve subjective stress scores, which may be part of why it improves testosterone given the well-known inverse relationship between cortisol and testosterone.

Extracted claim

Tongkat ali appears to lower cortisol and improve subjective stress scores, which may partly explain its testosterone-boosting effects given the inverse relationship between cortisol and testosterone.

Insufficient evidence to assessHigh confidence

None of the four provided studies directly measure cortisol levels or subjective stress scores in relation to tongkat ali supplementation. The RCT (PMID: 33541567) evaluated erectile function and test…

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

I take 400 milligrams per day of a high-potency standardized extract

Extracted claim

Huberman personally takes 400 milligrams per day of a high-potency standardized tongkat ali extract.

400 milligramshigh-potency standardized extractper day📍 Huberman's personal daily dose
Insufficient evidence to assessHigh confidence

The claim is a personal anecdote about Huberman's own supplementation habits (400 mg/day of standardized tongkat ali), which is inherently not a scientific claim subject to direct validation or refuta…

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

one that I actually take myself

Extracted claim

Huberman personally takes tongkat ali.

Insufficient evidence to assessHigh confidence

The claim is a personal anecdote — Huberman stating he personally takes tongkat ali — which is not a scientific claim that can be evaluated against published research. None of the four studies provide…

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

I take 400 milligrams per day of a high-potency standardized extract

Extracted claim

Huberman personally takes 400 milligrams per day of a high-potency standardized tongkat ali extract.

400 milligramshigh-potency standardized extractper day📍 Huberman's personal daily dose
Insufficient evidence to assessHigh confidence

The claim is a personal anecdote about Huberman's own supplement regimen (400 mg/day of standardized tongkat ali extract), not a scientific claim about efficacy or safety. The provided research abstra…

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

I take 400 milligrams per day of a high-potency standardized extract — look for products standardized to eurycomanone content. Quality control is a real issue in this category, so sourcing from reputable companies with third-party testing matters.

Extracted claim

Huberman personally takes 400 mg per day of a high-potency standardized Tongkat Ali extract, and recommends looking for products standardized to eurycomanone content from reputable companies with third-party testing.

400 milligramshigh-potency standardized extractper day📍 Huberman's own personal dosing protocol
Insufficient evidence to assessHigh confidence

Huberman's claim is a personal anecdote about his specific dosing regimen (400 mg/day) and product quality standards (eurycomanone standardization, third-party testing), which is not directly testable…

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

one that I actually take myself

Extracted claim

Huberman personally takes tongkat ali.

Insufficient evidence to assessHigh confidence

The claim is a personal anecdote — Huberman stating he personally takes tongkat ali — which is not a scientific claim about efficacy and therefore cannot be supported or contradicted by published rese…

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

I take 400 milligrams per day of a high-potency standardized extract

Extracted claim

Huberman personally takes 400 milligrams per day of a high-potency standardized tongkat ali extract.

400 milligramshigh-potency standardized extractper day📍 Huberman's personal daily dose
Insufficient evidence to assessHigh confidence

The claim is a personal anecdote about Huberman's individual supplementation practice (400 mg/day of standardized tongkat ali extract), which is not a testable scientific claim and therefore cannot be…

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

one that I actually take myself

Extracted claim

Huberman personally takes tongkat ali.

Insufficient evidence to assessHigh confidence

The claim is a personal anecdote about Huberman's own supplement use, which is not a scientific assertion subject to validation or contradiction by published research. None of the four studies provide…

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

I take 400 milligrams per day of a high-potency standardized extract

Extracted claim

Huberman personally takes 400 milligrams per day of a high-potency standardized tongkat ali extract.

400 milligramshigh-potency standardized extractper day📍 Huberman's personal daily dose
Insufficient evidence to assessHigh confidence

The claim is a personal anecdote about Huberman's own supplement regimen (400 mg/day of standardized tongkat ali extract), which is not a scientific claim subject to direct verification or refutation…

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

one that I actually take myself

Extracted claim

Huberman personally takes tongkat ali.

Insufficient evidence to assessHigh confidence

The claim is a personal anecdote — Huberman stating he personally takes tongkat ali — which is not a scientific assertion subject to empirical verification or falsification through published research.…

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

one that I actually take myself

Extracted claim

Huberman personally takes tongkat ali.

Insufficient evidence to assessHigh confidence

The claim is a personal anecdote about Huberman's own supplement use, which is not a scientific claim that can be evaluated against published research. The studies provided (including an RCT, PMID 335…

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

I take 400 milligrams per day of a high-potency standardized extract

Extracted claim

Huberman personally takes 400 milligrams per day of a high-potency standardized tongkat ali extract.

400 milligramshigh-potency standardized extractper day📍 Huberman's personal daily dose
Insufficient evidence to assessHigh confidence

The claim is a personal anecdote about Huberman's own supplement regimen (400 mg/day of a standardized tongkat ali extract), which by nature cannot be directly supported or contradicted by clinical re…

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

one that I actually take myself

Extracted claim

Huberman personally takes Tongkat Ali himself.

Insufficient evidence to assessHigh confidence

The claim is a personal anecdote about Huberman's own behavior — specifically that he personally takes Tongkat Ali. No published research can confirm or deny what an individual privately consumes. The…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Caution / warning

Quality control is a real issue in this category, so sourcing from reputable companies with third-party testing matters.

Extracted claim

Quality control is a real issue in the tongkat ali category; sourcing from reputable companies with third-party testing matters.

Insufficient evidence to assessHigh confidence

None of the four provided studies contain extractable key findings, populations, or limitations that directly address quality control, contamination, or third-party testing standards in the tongkat al…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Caution / warning

Quality control is a real issue in this category, so sourcing from reputable companies with third-party testing matters.

Extracted claim

Quality control is a real issue in the tongkat ali category; sourcing from reputable companies with third-party testing matters.

Partially supportedHigh confidence

The systematic review (PMID: 36013514) and the ED supplements analysis (PMID: 31036522) provide contextual support for quality control concerns, as the latter specifically examined online ED supplemen…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Caution / warning

Quality control is a real issue in this category, so sourcing from reputable companies with third-party testing matters.

Extracted claim

Quality control is a real issue in the tongkat ali category; sourcing from reputable companies with third-party testing matters.

Insufficient evidence to assessHigh confidence

None of the four studies provided contain extractable key findings, populations, or limitations data that directly address quality control issues, adulteration, or third-party testing practices within…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Caution / warning

Quality control is a real issue in this category, so sourcing from reputable companies with third-party testing matters.

Extracted claim

Quality control is a real issue in the tongkat ali category; sourcing from reputable companies with third-party testing matters.

Insufficient evidence to assessHigh confidence

None of the four provided studies include key findings, populations, or limitations data that would allow direct evaluation of Huberman's quality control claim. The systematic review (PMID 31036522) a…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Caution / warning

Quality control is a real issue in this category, so sourcing from reputable companies with third-party testing matters.

Extracted claim

Quality control is a significant issue for Tongkat Ali products, and sourcing from reputable companies with third-party testing is important.

Partially supportedHigh confidence

The systematic review on popular online ED supplements (PMID: 31036522) is the most directly relevant study here, as it evaluated Amazon-listed ED supplements for efficacy and safety concerns, implici…

Andrew Huberman
Andrew Huberman
Stanford School of Medicine / Huberman Lab
Caution / warning

Quality control is a real issue in this category, so sourcing from reputable companies with third-party testing matters.

Extracted claim

Quality control is a real issue in the tongkat ali category; sourcing from reputable companies with third-party testing matters.

Insufficient evidence to assessHigh confidence

None of the four provided studies contain extractable key findings, populations, or limitations data, making it impossible to directly assess whether the published literature supports Huberman's quali…