What does the research show about tongkat ali?

Tongkat ali

A meta-analysis of five small trials reported higher total testosterone, most clearly in men with low testosterone. Erectile function did not change overall in two pooled trials. Most trials tested one branded extract with maker involvement. EFSA found a root extract could damage DNA in lab and animal tests. One liver injury case is published.

Add to Bio HackChecked 2026-11-09

Status: Dietary supplement in the US. In the EU, an EFSA panel concluded in 2021 that the safety of one root extract proposed as a novel food had not been established.
Also called: Eurycoma longifolia, longjack, Malaysian ginseng, pasak bumi, Physta, LJ100, eurycomanone
Taken for: testosterone, libido, erectile function, muscle strength, stress, cortisol, male fertility, energy

Strong several reviews agree · Moderate one review or consistent trials · Limited one or a few small studies · Untested no study in people, listed with what it rests on

Shown to help3

ModerateShown to raise total testosterone in men, including men with low testosterone, in few small trials, one run partly by the maker.
LimitedOne small 4-week trial found lower tension, anger and saliva cortisol, and higher saliva testosterone, in moderately stressed adults.
LimitedOne small study without placebo found higher testosterone and grip strength over 5 weeks in active adults aged 57 to 72. The maker funded it.

Reported risks3

LimitedAnimal and lab studies only: EFSA concluded the extract can induce DNA damage, and that its safety was not established under any condition of use.How often is not known
LimitedCase reports: one man developed jaundice and raised liver enzymes shortly after starting tongkat ali, improving after he stopped.How often is not known
LimitedTwo of the trials on this page listed Biotropics Malaysia affiliations or funding. Funding for the pooled trials was not reported.How often is not known

What people take it for, and what was found

Shown to help3

ModerateStudied in men

Total testosterone

Shown to raise total testosterone in men, including men with low testosterone, in few small trials, one run partly by the maker.

The numbers and sources

Effect: Across 5 RCTs, tongkat ali raised total testosterone (SMD 1.352, 95% CI 0.565 to 2.138), with the effect confirmed in the hypogonadism subgroup [1]. In 105 men aged 50 to 70 with testosterone below 300 ng/dL, 200 mg a day raised total testosterone over placebo at weeks 4, 8 and 12, and free testosterone did not differ between groups [2].
Population: Healthy and hypogonadal men in 9 studies reviewed and 5 pooled [1]; ageing men in India for 12 weeks [2].
Sources: [1], [2]
Caveats: Few small trials. Two authors of [2], including the first author, were at Biotropics Malaysia Berhad, maker of the Physta extract it tested.

Limited

Stress hormones and mood

One small 4-week trial found lower tension, anger and saliva cortisol, and higher saliva testosterone, in moderately stressed adults.

The numbers and sources

Effect: In 63 moderately stressed adults (32 men, 31 women), 4 weeks of a hot-water root extract lowered tension (11%), anger (12%) and confusion (15%) scores, lowered salivary cortisol exposure by 16%, and raised salivary testosterone by 37% compared with placebo [6].
Population: 63 adults [6].
Sources: [6]
Caveats: One 4-week trial. The first author's listed affiliation is SupplementWatch. Cortisol and testosterone were measured in saliva.

Limited

Muscle strength

One small study without placebo found higher testosterone and grip strength over 5 weeks in active adults aged 57 to 72. The maker funded it.

The numbers and sources

Effect: In 25 physically active adults aged 57 to 72, 400 mg a day for 5 weeks raised total and free testosterone and handgrip force in men and women [7].
Population: 13 men and 12 women, single group [7].
Sources: [7]
Caveats: No placebo group. Funded by Biotropics Malaysia [7].

Not shown to help1

LimitedStudied in men

Erectile function

Limited evidence: pooled trials found no change in erectile function over placebo, though men with lower starting scores improved about 2 points.

The numbers and sources

Effect: Pooling 2 RCTs (139 participants), the change in IIEF-5 score at 12 weeks did not differ from placebo (WMD 0.91, 95% CI -1.50 to 3.33, I² 89.5%). Men with lower baseline scores improved by 2.15 points (95% CI 1.03 to 3.27) [3]. In a 6-month trial of 45 men with androgen deficiency, the largest improvement came with 200 mg a day combined with concurrent training [4]. A systematic review of 11 human studies found 7 reported an effect on male sexual health and 4 did not [5].
Population: Men with erectile dysfunction [3]; men averaging 47 years with androgen deficiency [4]; mixed designs [5].
Sources: [3], [4], [5]
Caveats: The trial in [4] had no supplement-only or training-only group.

Doses studied

Trials used 100 or 200 mg a day of a standardized water extract for 12 weeks [2], 200 mg a day for 6 months [4] and 400 mg a day for 5 weeks [7]. The EFSA novel food dossier proposed up to 200 mg a day for adults [8].

Risks

Reported risks3

LimitedHow often is not known

DNA damage in laboratory and animal tests

Animal and lab studies only: EFSA concluded the extract can induce DNA damage, and that its safety was not established under any condition of use.

The numbers and sources

How common: How often is not known: the sources give no rate.
Effect: EFSA's nutrition panel found positive results in an in vitro chromosome aberration test and in an in vivo comet assay at 2,000 mg/kg body weight in stomach and duodenum. It concluded the extract can induce DNA damage, particularly at first sites of contact, and that its safety had not been established under any condition of use [8].
Population: In vitro and animal studies [8].
Sources: [8]
Caveats: Applies to the specific standardized water extract assessed. No human genotoxicity data were reported.

LimitedHow often is not known

Liver injury

Case reports: one man developed jaundice and raised liver enzymes shortly after starting tongkat ali, improving after he stopped.

The numbers and sources

How common: How often is not known: the sources give no rate.
Effect: A 47-year-old man developed scleral icterus, raised liver enzymes and jaundice shortly after starting tongkat ali, and improved after stopping it. The authors describe it as the first reported case [9].
Population: One case report [9].
Sources: [9]
Caveats: A single case.

LimitedHow often is not known

Manufacturer involvement in the evidence

Two of the trials on this page listed Biotropics Malaysia affiliations or funding. Funding for the pooled trials was not reported.

The numbers and sources

How common: How often is not known: the sources give no rate.
Effect: Of the trials on this page, the 105-man testosterone trial listed Biotropics Malaysia affiliations [2], and the seniors study was funded by Biotropics Malaysia [7].
Population: Published trials [2][7].
Sources: [2], [7]
Caveats: Funding for the trials pooled in [1] and [3] is not reported in their abstracts.

Claims tested and not found

That tongkat ali improves erectile function overall. Pooled IIEF-5 change did not differ from placebo (WMD 0.91, 95% CI -1.50 to 3.33) [3].
That tongkat ali raises free testosterone. Free testosterone did not differ from placebo in the 105-man trial [2].

Sources

Leisegang K, Finelli R, Sikka S, et al. Eurycoma longifolia (Jack) Improves Serum Total Testosterone in Men: A Systematic Review and Meta-Analysis of Clinical Trials. Medicina. 2022. https://doi.org/10.3390/medicina58081047
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 & Nutrition Research. 2021. https://doi.org/10.29219/fnr.v65.5647
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. Complementary Therapies in Medicine. 2015. https://doi.org/10.1016/j.ctim.2015.07.009
Leitão AE, Vieira MCdS, 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. https://doi.org/10.1016/j.maturitas.2020.12.002
Thu HE, Mohamed IN, Hussain Z, et al. Eurycoma Longifolia as a potential adoptogen of male sexual health: a systematic review on clinical studies. Chinese Journal of Natural Medicines. 2017. https://doi.org/10.1016/S1875-5364(17)30010-9
Talbott SM, Talbott JA, George A, et al. Effect of Tongkat Ali on stress hormones and psychological mood state in moderately stressed subjects. Journal of the International Society of Sports Nutrition. 2013. https://doi.org/10.1186/1550-2783-10-28
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. Phytotherapy Research. 2014. https://doi.org/10.1002/ptr.5017
EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA), Turck D, Bohn T, et al. Safety of Eurycoma longifolia (Tongkat Ali) root extract as a novel food pursuant to Regulation (EU) 2015/2283. EFSA Journal. 2021. https://doi.org/10.2903/j.efsa.2021.6937
Kaliounji A, Shadid G, Saba H, et al. A Rare Case of Tongkat Ali-Induced Liver Injury: A Case Report. Cureus. 2024. https://doi.org/10.7759/cureus.56639

Everything in the library