Tongkat Ali: Testosterone Trials, Extracts and Safety

Table of contents

• Evidence summary
• What Tongkat Ali is
• Preparations and labeling
• How it works
• The hype vs the evidence
• Benefits by claim
• Claims and limits
• Safety findings and uncertainties
• Medicine and condition precautions
• Who should seek medical advice
• Studied doses and administration
• Human outcomes and preclinical limits
• Funding, conflicts and source roles
• Frequently asked questions
• Sources and funding notes

Evidence summary

Claim	Evidence	Source	Funding/conflict	Evidence boundary
Serum total testosterone in men	Five studies, seven comparisons: SMD 1.352 (95% CI 0.565–2.138); I²=87.27%	Leisegang 2022	Review declares no external funding or author conflicts; included commercial trial support is separate	Low-testosterone subgroup significant; normal-testosterone subgroup inconclusive. A shared placebo group appears in two dose comparisons.
Erectile function	Two trials, 139 randomized; pooled week-12 change WMD 0.91 (95% CI −1.50 to 3.33), not significant; I²=89.5%	Kotirum 2015	Review reports no financial funding; Ismail authored an included trial. Both trial originals disclose Biotropics support and employee authors (Ismail trial; Udani trial)	Both trials rated high risk of bias; positive comparison used two ingredients, with baseline imbalance.
Salivary hormones in moderately stressed adults	64 randomized, 63 completed; 200 mg/day Physta for four weeks; cortisol −16%, testosterone +37% compared with placebo	Talbott 2013	Biotropics funded SupplementWatch’s trial; manufacturer and supplement-company employee authors	Small, short study in men and women; not a serum-testosterone or clinical-treatment effect.
Testosterone or performance in healthy young men	Normal-testosterone subgroup: three comparisons, SMD 0.760 (95% CI −0.540 to 2.060), p=0.249	Leisegang 2022	Review-level disclosure does not establish every included trial’s finances	Inconclusive pool; hormone measurements do not establish a meaningful performance benefit.
Liver injury and long-term safety	A product-associated case; dose and purity not established, incidence unknown (LiverTox)	Kaliounji 2024; LiverTox chapter	Case authors declare no conflicts; separate funding not identified. LiverTox is an official safety synthesis (case declarations)	Temporal association and improvement after stopping do not prove causation or establish safe long-term dosing.

What Tongkat Ali is

Tongkat Ali is the common name for Eurycoma longifolia, also called Long Jack or Malaysian ginseng. It grows in Southeast Asia and has traditional medicinal uses, particularly root preparations. Modern products include powders, capsules and blends. The cited trials concern specific extracts, often Physta; their results do not establish that all commercial preparations have the same composition or effects (LiverTox; 2022 review; 2013 trial).

Online commentary promotes Tongkat Ali for testosterone and sometimes pairs it with Fadogia. These are examples of claims, not proof of benefit or evidence that the pairing is safe. NowPatient’s reported 234% search increase concerned UK searches in June 2022–July 2023; it is not a measurement of current global demand (NowPatient methodology; nsdr.co commentary).

Preparations and labeling

Preparation/label	Description	Studied or marketed example	Evidence boundary
Standardized water extract	Extracted root; composition depends on the product	Physta in seven of nine studies in the 2022 review (Table 1)	EFSA’s assessed extract specified 0.8–1.5% eurycomanone and 40–65% glycosaponins; standardization did not establish safety (EFSA composition and conclusion)
Physta in cited trials	Proprietary standardized root-water extract	Biotropics Malaysia; trial-specific dose and composition (Chinnappan trial; Ismail trial)	The cited studies do not compare Physta with every other brand or establish interchangeability with an LJ100-labeled product.
Extract-ratio labels	Describe claimed raw material/extract relationships	Ratios and extraction methods differ (Talbott background)	A ratio alone does not establish the measured composition, clinical effect or safety of the finished product (assessed extract).
Capsules	Dosage form, not an active-ingredient specification	100/200 mg Physta daily in one trial; 300 mg/day in another (2021 trial; 2012 trial)	These are study protocols, not a universal safe dose or proof that capsule products are equivalent.
Powder or multi-ingredient products	Composition and extraction can vary	Powders and blends are described by LiverTox	Evidence from a named single-extract trial cannot be transferred automatically to a blend or raw powder.
Traditional root preparation	Historical preparation differs from a defined modern extract	Traditional root use described in the 2013 trial background	The trials summarized here do not establish an equivalent dose or clinical effect for an unspecified root decoction.

How it works

The human mechanism remains uncertain. The stress paper discusses release from sex-hormone-binding globulin (SHBG) as a hypothesis, and the review discusses hormone production and aromatase pathways partly from animal research. The trials do not establish direct SHBG displacement in people. In one three-arm trial, free testosterone did not differ significantly from placebo despite total-testosterone findings (Talbott 2013; Leisegang 2022; Chinnappan Table 2).

A low baseline testosterone value does not establish the mechanism of response or diagnose every cause of symptoms. The reviewed hormone trials do not validate SHBG-displacement kinetics or prove that an extract can replace clinical assessment (2022 review; 2013 trial).

The hype vs the evidence

Claims such as “natural testosterone booster” and pairing with Fadogia appear in online supplement commentary. That commentary does not verify a clinical mechanism, an effective cycling schedule or safe combined use. Clinical trial results need to be assessed separately (nsdr.co example; testosterone review).

Leisegang et al. pooled five studies as seven comparisons: overall SMD 1.352 (95% CI 0.565–2.138; p=0.001), with high heterogeneity (I²=87.27%) and a publication-bias signal. The low-testosterone subgroup was significant; the normal-testosterone subgroup was inconclusive (p=0.249). Table 2 counts the same 35 placebo participants in both Chinnappan dose comparisons, and the Methods do not describe an adjustment for that dependence. Its 267 summed comparison entries are therefore not 267 distinct participants. The review declares no external funding or conflicts, while seven of nine systematically reviewed studies used Physta; the Chinnappan original discloses Biotropics funding and employee authors (review Methods/Table 2; original three-arm trial/declarations).

Kotirum et al. analyzed two trials with 139 randomized men and found no significant pooled week-12 change in IIEF-5 scores (WMD 0.91; 95% CI −1.50 to 3.33; I²=89.5%). The +2.15-point comparison (95% CI 1.03–3.27) came from the small Tongkat Ali plus Polygonum trial, which had 26 completers and imbalanced baseline scores. Both trials were rated at high risk of bias. The original combination paper reports a positive SHIM result but separately says IIEF-5 showed no significant difference, leaving the endpoint labeling unclear. The review-derived comparison does not establish isolated Tongkat efficacy or benefit predicted by baseline severity (Kotirum Methods/Tables 1–3; Udani Results/Table 4).

Talbott et al. randomized 64 moderately stressed adults; 63 completed four weeks of 200 mg/day Physta or placebo. The reported cortisol −16% and testosterone +37% were salivary values compared with placebo, not a 37% serum-testosterone increase from each person’s baseline. Tension, anger and confusion scores improved, while depression, vigor, fatigue and overall mood did not show significant between-group improvement. Biotropics funded the trial through SupplementWatch; manufacturer and supplement-company employee authors were disclosed (Talbott Methods/Results/declarations).

The reviewed evidence contains a testosterone-marker signal, with substantial statistical and reporting limitations. It does not establish a universal boost, clinical equivalence to testosterone treatment or a safe long-term regimen. Low-baseline and normal-baseline subgroup results differ, but the subgroup comparisons do not prove which individual will benefit (2022 review; EFSA safety opinion).

Benefits by claim

Serum total testosterone in men

The 2022 review reported a positive pooled total-testosterone result with high heterogeneity, publication-bias signals and a shared-control issue. The normal-testosterone subgroup was inconclusive. These findings concern selected study populations and extracts and do not establish a predictable personal or clinical-treatment benefit (Leisegang 2022).

Testosterone/cortisol under psychological stress

One four-week, manufacturer-funded trial reported salivary cortisol and testosterone differences versus placebo in moderately stressed men and women. These markers and selected mood-scale findings do not establish a treatment for stress disorders or a generalized serum-testosterone effect (Talbott 2013).

Erectile function

The cited two-trial review found no significant pooled improvement. Its positive comparison used two ingredients, involved only 26 completers and had baseline imbalance; it cannot establish that Tongkat Ali alone treats erectile dysfunction (Kotirum 2015; combination trial).

General “T-boost” / performance in healthy young men

The normal-testosterone subgroup did not show a statistically significant pooled effect. The small, heterogeneous hormone studies do not establish a clinically meaningful performance benefit for healthy young men or prove there is no effect in every setting (Leisegang 2022).

Claims and limits

Claim	Assessment	Basis
Raises serum total testosterone in low-testosterone men	Positive pooled marker signal, limited confidence	High heterogeneity, small studies and repeated comparisons; no established universal clinical benefit (Leisegang 2022).
Improves erectile function broadly	Not established by the cited pool	Two-trial overall result nonsignificant; positive individual comparison tested a combination (Kotirum 2015).
“37% testosterone boost” as a general claim	Misleading without measurement and comparator	Salivary testosterone was 37% higher versus placebo after four weeks in one commercially funded, mixed-sex stress trial (Talbott 2013).
Universal testosterone or performance benefit	Not established	Normal-testosterone pool inconclusive; a significant subgroup does not identify personal responders (Leisegang 2022).
Safe at any dose for long-term use	Not established	Short-trial limits, uncertain liver-injury association and assessed-extract genotoxicity concern (LiverTox; EFSA).

Safety findings and uncertainties

Safety issue	Evidence scope	Limit	Source
Gastrointestinal symptoms, headache or rash	Reported in short studies or described by the safety synthesis	LiverTox calls conventional-dose side effects uncommon, but does not provide a reliable incidence for all extracts or longer use	LiverTox
Genotoxicity concern	EFSA assessed a particular standardized water extract	Cell-test and high-dose rat DNA-damage findings do not quantify ordinary-dose human harm; safety nonetheless was not established	EFSA 2021 opinion
Possible liver injury	Potentially serious; incidence unknown	A reported product-associated case had unknown dose/composition and incomplete follow-up; alternative explanations remain possible	LiverTox; Kaliounji case
Product composition or adulteration	Testing is product-specific	Extract specifications vary. OPSS describes reports of contamination/adulteration; this does not establish a rate for all products or prove that a particular tested batch is safe	LiverTox; OPSS

Medicine and condition precautions

Medicine/condition	What the cited evidence establishes	What remains uncertain	Practical boundary
Blood-pressure medicines	Selected stable hypertensive participants could enter the Ismail trial	This is not a dedicated drug-interaction study or proof of additive blood-pressure lowering	Discuss the exact extract and medication with a clinician; do not infer compatibility from animal effects (trial eligibility/Methods; FDA consumer guidance).
Diabetes medicines	Ismail allowed selected stable patients on metformin; Chinnappan excluded uncontrolled diabetes	These protocols do not establish a class-wide interaction with insulin, metformin or sulfonylureas	Keep prescribed treatment and seek individual advice before adding a supplement (Ismail Methods; Chinnappan Methods; FDA guidance).
Hormone-sensitive disease or hormonal treatment	Chinnappan excluded prostate cancer/other malignancy	Trial findings do not establish safety, benefit or a quantified additive hormonal interaction in these patients	Seek specialist advice rather than applying a testosterone-marker claim to these conditions (original exclusions).
Pregnancy or breastfeeding	Excluded from the intended population for EFSA’s assessed supplement	That opinion does not establish safety for pregnancy, lactation or children	Avoid self-directed use in these groups; the assessed extract lacked an established safe condition of use (EFSA population and conclusion).

The trials discussed here were designed around hormone, symptom or other efficacy outcomes; they do not establish interaction magnitudes for every medicine. Selected participants using a medicine, or a null routine lab finding, do not prove compatibility. FDA advises discussing supplement use with a clinician or pharmacist. The interaction table therefore describes evidence boundaries, not confirmed additive effects or an exhaustive compatibility list (Ismail Methods; Chinnappan Methods; FDA consumer information).

Who should seek medical advice

• Pregnant or breastfeeding people and children: EFSA’s proposed-use population excluded these groups and the assessed extract’s safety was not established (EFSA opinion).
• People with prostate cancer, other malignancy or hormonal treatment: the cited trial excluded relevant disease, so it cannot establish suitability; seek specialist advice (Chinnappan exclusions).
• People with liver disease or a history of supplement-related liver injury: avoid self-directed use and discuss the risk with a clinician. LiverTox notes limited applicability of trials and possible more severe injury with pre-existing liver disease (LiverTox).
• People taking blood-pressure medicines: ask about the exact product; selected trial enrollment does not establish a safe combination or a proven blood-pressure interaction (Ismail Methods; FDA advice).
• People taking diabetes medicines: keep prescribed treatment and seek advice before supplement use; the cited trials do not establish class-wide compatibility or an additive glucose-lowering effect (Ismail Methods; Chinnappan Methods; FDA advice).
• For any male-enhancement blend, inspect the full ingredient list and product-specific testing. OPSS reports contamination/adulteration concerns in Tongkat-containing products; a quality seal does not establish clinical benefit or erase the assessed-extract safety concern (OPSS; EFSA).

Studied doses and administration

Preparation	Studied protocol	Limit
Physta water extract	200 mg/day for four weeks in a mixed-sex stress trial (Talbott); 100 or 200 mg/day for 12 weeks in selected older men with low testosterone (Chinnappan)	Specific trial protocols; no universal recommended dose, optimum duration or guarantee of long-term safety.
Other extract protocols	The review describes 100–600 mg/day or weight-based dosing over three days to six months; formulations and populations differ (Table 1)	No dose equivalence across brands, raw root, ratios or combinations, and no verified cycling or best-time-of-day regimen.
Traditional root or multi-ingredient product	Products and preparations vary (LiverTox)	The cited extract trials do not establish a corresponding root dose, ideal timing or safety of a blend.

Human outcomes and preclinical limits

Human trials supply the hormone and erectile-function outcomes discussed here. Animal and laboratory work supplies proposed mechanisms; it does not confirm those mechanisms or clinical benefits in people. EFSA’s genotoxicity findings are preclinical safety evidence for the assessed extract. They matter to the safety evaluation while leaving ordinary-dose human risk unquantified (stress trial; testosterone review; EFSA safety assessment).

Funding, conflicts and source roles

Follow the money

Research funding at a glance

Funding & backers→Source & study→Claim & limits

5 disclosure entries. The counts below summarize independence tiers explicitly assigned in this article. They count disclosures, not studies, funding amounts or evidence quality.

No single explicit tier could be mapped. This graphic does not assign a new tier or infer independence.

Consult this article’s source and funding notes for named funders, countries, relationships and exceptions where available. Institutional backing, researcher interests and trial sponsorship are separate questions. Public funding alone does not establish independence; commercial ties alone do not prove a claim false. This overview is not a new financial audit.

Source	Declared funding/roles	Interpretation and remaining limits
Leisegang 2022	No external funding or review-author conflicts declared. Chinnappan disclosed Biotropics cash and two employee authors (trial declarations).	No-external-funding review statement does not establish every included trial’s finances or remove statistical limitations. All trial supply contracts/ultimate backing were not traced.
Kotirum 2015	No financial funding reported; Ismail was an included-trial author, without screening/selection role. Both originals disclose Biotropics funding and employee authors (Ismail ACK; Udani disclosures).	Udani also disclosed consulting and ongoing Medicus Research grants. Funding supports scrutiny; it does not prove that every finding is false. Exact amounts/supply terms not established.
Talbott 2013	Biotropics funded SupplementWatch to conduct the trial; manufacturer and supplement-company employee authors	Commercially linked result; the declaration of no directly competing interests does not cancel disclosed funding/employment. Exact amounts/ultimate backing not traced.
LiverTox	Official NIDDK/NLM clinical safety resource	A safety synthesis, not an independent clinical replication or financial clearance of every cited study. The liver-injury association remains uncertain.
EFSA minutes; final opinion	Biotropics industry-submitted dossier; European Commission request for regulatory assessment	Minutes report no relevant conflicts identified in screening. Proprietary test reports and every expert’s full financial chain were not independently audited; regulatory safety opinion is distinct from clinical efficacy.

Review-level no-funding or no-conflict declarations and commercial trial support are different facts. Biotropics funded the stress trial, the Chinnappan trial and both erectile-function trials discussed here, with disclosed employee or consultant roles. Exact funding amounts, product-supply terms and ultimate corporate backing remain unresolved. These disclosures accompany the methodological limits; neither an academic affiliation nor industry funding by itself settles whether a clinical claim is reliable (stress trial; Chinnappan; Ismail; Udani; review).

Frequently asked questions

Does Tongkat Ali actually raise testosterone?

The cited 2022 review reported a positive pooled serum total-testosterone result, but heterogeneity, publication-bias signals, small studies and repeated dose comparisons limit confidence. The normal-testosterone subgroup was inconclusive. This is not a guaranteed response or proof that a product can replace clinical care (Leisegang 2022).

Is the “cortisol down 16%, testosterone up 37%” stat trustworthy?

The trial reported salivary cortisol 16% lower and salivary testosterone 37% higher than placebo after four weeks, among 63 completers of both sexes. It did not establish a 37% serum-testosterone rise for each person. Biotropics funded the trial and commercial employee authors were disclosed (Talbott Methods/Results/COI).

Will Tongkat Ali improve erectile function?

The cited two-trial review found no significant pooled erectile-function improvement. The positive individual comparison involved Tongkat Ali plus Polygonum, only 26 completers, baseline imbalance and reporting limitations. It does not isolate Tongkat’s effect; both underlying originals disclose Biotropics funding and employee authors (Kotirum 2015; Ismail; Udani).

How does Tongkat Ali supposedly work?

The mechanism remains unconfirmed in humans. SHBG release and altered hormone production are hypotheses partly based on preclinical research. The stress trial did not directly establish either pathway; the Chinnappan trial did not show a free-testosterone difference versus placebo despite total-testosterone findings (Talbott; review; Chinnappan Table 2).

Is Tongkat Ali safe?

An established safe long-term regimen cannot be inferred from short trials. LiverTox describes a possible liver-injury association, with unknown dose/product composition and uncertain causality. EFSA found DNA-damage concerns and could not establish a safe condition of use for the submitted standardized extract. That does not measure human harm at ordinary doses or a universal risk for every preparation, but it precludes treating standardization as proof of safety (LiverTox; EFSA opinion).

What does FDA regulation say about supplements?

FDA states that it does not approve dietary-supplement safety and effectiveness before marketing; manufacturers are responsible for safety and lawful labeling. Availability or a supplement label therefore is not FDA verification of Tongkat efficacy or product safety. These pages do not settle every extract’s ingredient status or sporting eligibility; check the relevant authority and exact product rather than assuming blanket permission (FDA consumer guidance; FDA oversight).

Sources and funding notes

• Leisegang et al. 2022 — five-study testosterone pool; high heterogeneity, publication-bias signals and repeated/shared-control comparisons. Review reports no external funding/conflicts; underlying finance is separate.
• Kotirum et al. 2015 — two-trial erectile-function pool, nonsignificant overall change. No financial funding reported; included-trial author role disclosed. Underlying originals: Ismail 2012 and Udani 2014, both Biotropics funded with employee authors.
• Talbott et al. 2013 — four-week salivary-hormone/mood trial, manufacturer-funded with commercial employee authors. Chinnappan et al. 2021 — three-arm serum-testosterone trial; Biotropics funding and employee roles, free-testosterone between-group result null.
• NIH LiverTox, NCBI Bookshelf — official clinical safety synthesis; possible liver-injury association, unknown incidence and incomplete causal/product information.
• Kaliounji et al. 2024 — case after a Tongkat-containing product; dose/brand/chemical analysis and complete recovery not documented. No conflicts declared; separate funding not identified.
• EFSA 118th plenary minutes — Biotropics applicant, adoption date and conflict-screening statement; procedural record, not a clinical trial.
• EFSA 2021 safety opinion — standardized root extract novel-food assessment, based partly on applicant-submitted proprietary toxicology; DNA-damage concern and safety not established.
• NowPatient — commercial provider’s search-interest report for UK June 2022–July 2023, used only as historical online-claim context. FDA consumer information — official supplement-marketing and safety-advice reference.
• nsdr.co — online supplement commentary; original podcast attribution and clinical protocols not verified from that page. OPSS — official military-oriented evidence and product-risk summary, not a universal sporting-eligibility certificate.

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