Supplements

Tongkat Ali

Updated · 26 sources · Editorial policy

Tongkat ali is the root of Eurycoma longifolia, a slow-growing shrubby tree native to Southeast Asia. It is also sold as “Long Jack” or “Malaysian ginseng.” Traditional medicine has used its roots, leaves and bark for many conditions, and in the US it is now sold as a dietary supplement promoted to raise testosterone and improve athletic performance (LiverTox).

It has no approved medical use, and US law does not let FDA approve dietary supplements before they are sold. The human evidence is small: a 2022 meta-analysis pooled just five randomized trials (232 men) and found a testosterone increase in men with low testosterone, but not a significant one in men with normal levels. Most trials tested a single commercial water extract, and several were run or funded by its manufacturer.

This page summarizes what the clinical trials, case reports and regulators report. It is for education only and is not medical advice.

Property Detail
Type Herbal dietary supplement (root extract)
Plant Eurycoma longifolia Jack, family Simaroubaceae; native to Southeast Asia
Main marker compound Eurycomanone, a quassinoid (C₂₀H₂₄O₉)
Route Oral (capsules, powders, extracts added to coffee and tea)
Doses used in trials 100–600 mg/day of root extract, for 7 days to 6 months
Half-life No human data. Eurycomanone half-life was 0.30 h in rats and mice
Effect on testosterone Pooled SMD 1.35 (95% CI 0.57–2.14) in 5 RCTs; significant only in men with low testosterone
US status Sold as a dietary supplement; not FDA-approved for any use; not a controlled substance
WADA status Not named on the 2026 Prohibited List

What it is

Tongkat ali products are made from the dried root. The root contains many compound families, including quassinoids, canthin-6-one alkaloids and others (Leisegang et al., Medicina 2022). The plant belongs to the Simaroubaceae family, and the quassinoid found at the highest concentration in the root extract is eurycomanone (Low et al., J Ethnopharmacol 2013). Eurycomanone (C₂₀H₂₄O₉, molecular weight 408.4 g/mol) is used as the marker compound for standardizing extracts (PubChem).

Most clinical trials used one product: Physta, a freeze-dried water extract of the root made by Biotropics Malaysia. In the 2021 trial in older men, it was specified as 0.8–1.5% eurycomanone, at least 22% protein, 30% polysaccharide and 40% glycosaponin (Chinnappan et al., Food Nutr Res 2021). Results from this extract may not apply to other products, whose content can differ widely (see Quality and contamination below).

Proposed mechanism

How tongkat ali might raise testosterone is not established in humans. The main lab finding comes from isolated rat testicular (Leydig) cells in culture. There, eurycomanone raised testosterone production in a dose-dependent way and appeared to block aromatase, the enzyme that converts testosterone to estrogen (Low et al., 2013).

Human data do not fit that picture neatly:

  • In 32 young men given 600 mg/day for 2 weeks, testosterone and free testosterone rose, but estradiol also rose. LH, FSH and SHBG did not change (Chan et al., Andrologia 2021).
  • In older men with low testosterone, SHBG did not change over 12 weeks (Chinnappan et al., 2021).

How it behaves in the body

No study has measured how tongkat ali compounds are absorbed or cleared in people. The available data come from rodents:

Measure (eurycomanone) Finding Source
Half-life 0.30 h in rats and mice, as pure compound or in extract Ahmad et al., Pharmaceutics 2018
Oral bioavailability 11.8% in rats; 54.9% in mice Ahmad et al., 2018
Absorption Poor across biological membranes; stable once absorbed Ahmad et al., 2018

The authors noted that the large difference between rats and mice means these numbers cannot be directly extrapolated to humans. Any “half-life” quoted for tongkat ali in people is therefore not based on measured human data.

Regulatory status

  • United States. Tongkat ali is sold as a dietary supplement. Under the Dietary Supplement Health and Education Act (DSHEA), “FDA does not have the authority to approve dietary supplements before they are marketed,” and manufacturers carry the initial responsibility for safety (FDA). It is not listed as a controlled substance in 21 CFR 1308.13.
  • Sport. Tongkat ali is not named on the WADA 2026 Prohibited List. In a placebo-controlled crossover trial in 13 male recreational athletes, 400 mg/day for 6 weeks did not change the urinary testosterone:epitestosterone ratio used in doping tests (Chen et al., Int J Prev Med 2014). This says nothing about contaminated products.

What the research shows

Testosterone

The largest pooled analysis included five randomized trials with 232 men, testing 100–600 mg/day (Leisegang et al., 2022):

Group Pooled effect on total testosterone (SMD) 95% CI Significant?
All men 1.35 0.57–2.14 Yes
Men with normal testosterone (3 trials) 0.76 −0.54 to 2.06 No
Men with testosterone under 300 ng/dL (2 trials) 1.86 0.72–3.00 Yes

SMD (standardized mean difference) expresses the effect in standard-deviation units rather than ng/dL. The results came with important caveats:

  • Heterogeneity was very high (I² = 87%), meaning the trials disagreed a lot.
  • Both Egger’s and Begg’s tests suggested publication bias in the low-testosterone group.
  • One of the five trials was an unpublished PhD dissertation.

A 2024 systematic review of 27 marketed “testosterone boosters” concluded that most fail to raise testosterone. It rated E. longifolia only as “possibly effective” for men with late-onset hypogonadism and for healthy men, based on three studies (Morgado et al., Int J Impot Res 2024).

The individual studies show how modest the absolute changes were:

Study Design and population Daily dose, duration Total testosterone (mean, ng/dL)
Chinnappan 2021 RCT, 105 men aged 50–70 with testosterone under 300 ng/dL 100 or 200 mg Physta, 12 weeks 200 mg: 200.5 → 225.0; 100 mg: 187.3 → 203.8; placebo: 183.0 → 177.9
Leitão 2021 RCT, 45 men with androgen-deficiency symptoms (4 arms, with or without exercise) 200 mg, 6 months Extract-only arm: 278.2 → 400.3; placebo: 281.5 → 258.5 (as tabulated by Leisegang 2022)
Chan 2021 Controlled trial, 32 healthy men aged 18–30 600 mg, 2 weeks 802 → 924; placebo 791 → 769 (as tabulated by Leisegang 2022)
Ismail 2012 RCT, 109 men aged 30–55 300 mg Physta, 12 weeks No significant change vs placebo
Tambi 2012 Uncontrolled, 76 men with late-onset hypogonadism 200 mg, 1 month 163 → 240
Henkel 2014 Uncontrolled pilot, 13 men and 12 women aged 57–72 400 mg, 5 weeks Men: 384 → 442

In the Chinnappan trial, the largest and best-reported one, the 200 mg group’s average rose by about 25 ng/dL and was still under 300 ng/dL after 12 weeks. That trial was funded by Biotropics Malaysia, and two authors were company employees. Free testosterone did not differ significantly from placebo.

Uncontrolled studies such as Tambi 2012 cannot separate the supplement’s effect from placebo effects or normal day-to-day variation in testosterone.

Sexual function

A 2015 meta-analysis found only two eligible randomized trials (139 men). Overall, tongkat ali did not significantly improve erectile function scores on the IIEF-5 questionnaire: mean difference 0.91 points (95% CI −1.50 to 3.33), with high heterogeneity. In men with lower baseline scores, there was an improvement of 2.15 points (95% CI 1.03–3.27) (Kotirum et al., Complement Ther Med 2015).

In the 109-man Ismail trial, 300 mg/day for 12 weeks improved the physical functioning domain of a quality-of-life survey (SF-36) compared with placebo, and the extract group reported higher IIEF erectile function scores (Ismail et al., 2012). In the 6-month Leitão trial, erectile function improved with both the extract and exercise, and most with the two combined (Leitão et al., Maturitas 2021).

Muscle, strength and exercise

The evidence for muscle or performance benefit is weak:

  • Older adults. Handgrip strength rose in the uncontrolled 5-week pilot in 25 seniors (Henkel et al., 2014). With no placebo group, this cannot be attributed to the supplement.
  • Older men with low testosterone. Muscle strength rose within each Physta group at 12 weeks, but this was a within-group comparison, not a comparison with placebo (Chinnappan et al., 2021).
  • Athletes. In 18 young rugby players, 400 mg/day for 7 days had no effect on salivary testosterone or cortisol, jump performance, soreness or creatine kinase after damaging exercise (Zakaria et al., Biol Sport 2023).

No trial has measured lean body mass gains comparable to those seen with anabolic drugs.

Stress and mood

In 63 moderately stressed adults (32 men, 31 women), 200 mg/day for 4 weeks lowered tension, anger and confusion scores compared with placebo. Salivary cortisol was 16% lower and salivary testosterone 37% higher (Talbott et al., JISSN 2013). These were saliva measurements, not serum, and one author was an employee of the extract’s manufacturer.

Side effects and risks

Trial safety data

Short trials of standardized extract reported few side effects:

Trial Dose, duration Adverse events reported
Chinnappan 2021 100–200 mg, 12 weeks 8 events in total, no serious ones; mostly digestive (constipation, indigestion, abdominal pain) in 3 people per extract group; 1 case of itching; none judged related
Ismail 2012 300 mg, 12 weeks 11 mild to moderate events in 11 people on extract; all judged unlikely to be related
Talbott 2013 200 mg, 4 weeks Unusual fatigue in 2 on extract and 1 on placebo; no change in liver enzymes
Chen 2014 400 mg, 6 weeks No significant changes in liver or kidney function tests

These trials were small and lasted at most 6 months, so they cannot detect rare or long-term harms.

Liver injury

The NIH’s LiverTox database notes that reports of clinically apparent liver injury attributed to tongkat ali in bodybuilders have recently appeared (LiverTox). In one published case, a 47-year-old man developed jaundice about a week after starting tongkat ali for bodybuilding. His ALT peaked at 876 U/L and total bilirubin at 14.3 mg/dL, and he improved after stopping it (Kaliounji et al., Cureus 2024). Single case reports cannot prove cause, and the product was not tested.

In rats, powdered root at up to 2 g/kg/day for 13 weeks caused no adverse effects, and the acute oral lethal dose was above 6 g/kg (Li et al., 2013). Animal toxicity data do not rule out rare idiosyncratic liver injury in people.

Heart rhythm

One case report describes new atrial flutter (a fast, abnormal heart rhythm) in a healthy 71-year-old man two days after he started a 668 mg/day tongkat ali capsule. Other causes were ruled out, and the author rated the link as “probable” (Ali, Cureus 2025).

Drug interaction: propranolol

In a randomized crossover study in 14 healthy young men, taking a tongkat ali water extract with the blood pressure drug propranolol (80 mg) changed how much of the drug was absorbed (Salman et al., J Clin Pharm Ther 2010):

Propranolol measure Change with tongkat ali
Total exposure (AUC) −29%
Peak level (Cmax) −42%
Time to peak (Tmax) ≈86% longer
Elimination half-life No significant change

The effect seemed to come from reduced absorption. Blood pressure response was not affected in these healthy volunteers, but the authors advised caution when combining the two.

Who should be cautious

The trials above enrolled mostly healthy adults. They provide no safety data for:

  • people with liver disease or a history of drug-induced liver injury;
  • people with heart rhythm disorders;
  • people taking propranolol or other prescription drugs that could interact;
  • pregnant or breastfeeding women;
  • children and adolescents.

Quality and contamination

Product quality is a documented problem:

  • Mercury. In 100 tongkat ali products sold in Malaysia, 36% contained 0.52–5.30 ppm of mercury, above Malaysia’s limit for traditional medicines (Ang et al., Int J Toxicol 2004).
  • Wrong or missing plant. DNA testing of tongkat ali herbal products found 37% authentic and 27% adulterated. Some products identified as authentic did not contain the expected eurycomanone marker on HPLC testing (Abubakar et al., Pharm Biol 2018).
  • Hidden drugs. Of ten commercial tongkat ali products screened, two bought online appeared to contain a sildenafil analogue, a relative of the erectile dysfunction drug Viagra (Said et al., Food Chem 2014).

Because FDA does not review supplements before sale, the label is the manufacturer’s own claim. The positive trials used a specific standardized extract, so results from them do not carry over to unstandardized powders.

Key takeaways

  • A herbal supplement, not a drug. Tongkat ali is the root of Eurycoma longifolia; it has no approved medical use and is sold in the US without FDA pre-market review.
  • Small, inconsistent testosterone effect. Pooled trials show a rise mainly in men with low testosterone, with high heterogeneity and signs of publication bias. In the best-reported trial, average testosterone rose by about 25 ng/dL.
  • Evidence leans on one product. Most trials tested the same manufacturer’s water extract, and several were funded or co-authored by that company.
  • No real muscle-building evidence. Strength results are mostly uncontrolled or within-group, and a trial in rugby players found no effect.
  • No human pharmacokinetic data. The only half-life data are from rodents (about 0.3 h for eurycomanone).
  • Real-world risks are product quality and rare reactions. Mercury contamination, fake or adulterated products, hidden sildenafil analogues, isolated liver-injury and arrhythmia reports, and a propranolol interaction have all been documented.

Sources

  1. National Institute of Diabetes and Digestive and Kidney Diseases. LiverTox: Tongkat Ali. Updated October 18, 2024. NCBI Bookshelf.
  2. Leisegang K, Finelli R, Sikka SC, Panner Selvam MK. Eurycoma longifolia (Jack) improves serum total testosterone in men: a systematic review and meta-analysis of clinical trials. Medicina (Kaunas). 2022;58(8):1047. PubMed.
  3. Morgado A, Tsampoukas G, Sokolakis I, et al. Do “testosterone boosters” really increase serum total testosterone? A systematic review. Int J Impot Res. 2024;36(4):348–364. PubMed.
  4. National Center for Biotechnology Information. PubChem Compound Summary: Eurycomanone (CID 13936691). PubChem.
  5. Low BS, Choi SB, Abdul Wahab H, et al. Eurycomanone, the major quassinoid in Eurycoma longifolia root extract increases spermatogenesis by inhibiting the activity of phosphodiesterase and aromatase in steroidogenesis. J Ethnopharmacol. 2013;149(1):201–207. PubMed.
  6. Chinnappan SM, George A, Pandey P, et al. Effect of Eurycoma longifolia standardised aqueous root extract-Physta on testosterone levels and quality of life in ageing male subjects: a randomised, double-blind, placebo-controlled multicentre study. Food Nutr Res. 2021;65:5647. PubMed.
  7. Chan KQ, Stewart C, Chester N, et al. The effect of Eurycoma Longifolia on the regulation of reproductive hormones in young males. Andrologia. 2021;53(4):e14001. PubMed.
  8. Ahmad N, Samiulla DS, Teh BP, et al. Bioavailability of eurycomanone in its pure form and in a standardised Eurycoma longifolia water extract. Pharmaceutics. 2018;10(3):90. PubMed.
  9. Food and Drug Administration. Questions and answers on dietary supplements. FDA.
  10. Drug Enforcement Administration. Schedules of controlled substances: Schedule III. 21 CFR 1308.13. eCFR.
  11. World Anti-Doping Agency. World Anti-Doping Code International Standard: Prohibited List 2026. WADA 2026 Prohibited List.
  12. Chen CK, Mohamad WM, Ooi FK, et al. Supplementation of Eurycoma longifolia Jack extract for 6 weeks does not affect urinary testosterone: epitestosterone ratio, liver and renal functions in male recreational athletes. Int J Prev Med. 2014;5(6):728–733. PubMed.
  13. Leitão AE, Vieira MCS, Pelegrini A, et al. A 6-month, double-blind, placebo-controlled, randomized trial to evaluate the effect of Eurycoma longifolia (Tongkat Ali) and concurrent training on erectile function and testosterone levels in androgen deficiency of aging males (ADAM). Maturitas. 2021;145:78–85. PubMed.
  14. Ismail SB, Wan Mohammad WM, George A, et al. Randomized clinical trial on the use of PHYSTA freeze-dried water extract of Eurycoma longifolia for the improvement of quality of life and sexual well-being in men. Evid Based Complement Alternat Med. 2012;2012:429268. PubMed.
  15. Tambi MI, Imran MK, Henkel RR. Standardised water-soluble extract of Eurycoma longifolia, Tongkat ali, as testosterone booster for managing men with late-onset hypogonadism? Andrologia. 2012;44(Suppl 1):226–230. PubMed.
  16. Henkel RR, Wang R, Bassett SH, et al. Tongkat Ali as a potential herbal supplement for physically active male and female seniors: a pilot study. Phytother Res. 2014;28(4):544–550. PubMed.
  17. Kotirum S, Ismail SB, Chaiyakunapruk N. Efficacy of Tongkat Ali (Eurycoma longifolia) on erectile function improvement: systematic review and meta-analysis of randomized controlled trials. Complement Ther Med. 2015;23(5):693–698. PubMed.
  18. Zakaria AZ, Washif JA, Lim BH, Nosaka K. Effects of Eurycoma longifolia Jack supplementation on eccentric leg press exercise-induced muscle damage in rugby players. Biol Sport. 2023;40(3):691–697. PubMed.
  19. Talbott SM, Talbott JA, George A, Pugh M. Effect of Tongkat Ali on stress hormones and psychological mood state in moderately stressed subjects. J Int Soc Sports Nutr. 2013;10(1):28. PubMed.
  20. Kaliounji A, Shadid G, Saba H, Ahlawat S. A rare case of Tongkat Ali-induced liver injury: a case report. Cureus. 2024;16(3):e56639. PubMed.
  21. Li CH, Liao JW, Liao PL, et al. Evaluation of acute 13-week subchronic toxicity and genotoxicity of the powdered root of Tongkat Ali (Eurycoma longifolia Jack). Evid Based Complement Alternat Med. 2013;2013:102987. PubMed.
  22. Ali M. Tongkat Ali-induced atrial flutter: a probable case. Cureus. 2025;17(9):e92024. PubMed.
  23. Salman SA, Amrah S, Wahab MS, et al. Modification of propranolol’s bioavailability by Eurycoma longifolia water-based extract. J Clin Pharm Ther. 2010;35(6):691–696. PubMed.
  24. Ang HH, Lee EL, Cheang HS. Determination of mercury by cold vapor atomic absorption spectrophotometer in Tongkat Ali preparations obtained in Malaysia. Int J Toxicol. 2004;23(1):65–71. PubMed.
  25. Abubakar BM, Salleh FM, Shamsir Omar MS, Wagiran A. Assessing product adulteration of Eurycoma longifolia (Tongkat Ali) herbal medicinal product using DNA barcoding and HPLC analysis. Pharm Biol. 2018;56(1):368–377. PubMed.
  26. Said MM, Gibbons S, Moffat AC, Zloh M. Rapid detection of sildenafil analogue in Eurycoma longifolia products using a new two-tier procedure of the near infrared (NIR) spectra database. Food Chem. 2014;158:296–301. PubMed.