Tongkat ali is a slender tree native to Malaysia, Indonesia and neighbouring countries. Its root is traditionally boiled into a tonic, and modern supplements usually contain a standardised water extract of the root. It is one of the most common ingredients in testosterone-support products, often alongside several other herbs.
Among herbal ingredients studied for testosterone, tongkat ali has some of the most encouraging data. A 2022 meta-analysis pooling five randomised trials found a significant increase in total testosterone, a finding confirmed in men with hypogonadism, and the authors described it as a promising option that needs further research1. A 2024 systematic review of 52 studies on testosterone-support supplements rated tongkat ali 'possibly effective' for both healthy men and men with late-onset hypogonadism2.
Research is ongoing. The trials so far used different extracts and groups of men, and larger studies would help show who is most likely to benefit.
Does tongkat ali increase testosterone?
Pooled trials show an increase in total testosterone, including in men who started with low levels. A separate systematic review rated it 'possibly effective' for healthy men and men with late-onset hypogonadism.
The 2022 meta-analysis included nine studies in its systematic review and pooled five randomised trials. Most reported a significant rise in total testosterone in both healthy volunteers and men with hypogonadism, and the authors described tongkat ali as a promising option that still needs more research before clinical use1.
A rise on a blood test and how you feel day to day are related but separate questions. If you have symptoms of low testosterone, get your levels measured properly; our guide to testosterone and sex drive explains how the two are linked.
What have studies found on tongkat ali and erections?
Two randomised trials have looked at erectile function over 12 weeks. In men whose starting scores were lower, tongkat ali improved scores by about two points compared with placebo.
The 2015 meta-analysis pooled the two trials, involving 139 men, and used the five-item International Index of Erectile Function (IIEF-5). Results varied between the two trials, and the overall difference from placebo was not statistically significant; the improvement appeared in the subgroup of men with lower starting scores3.
If erections have changed, see a GP. Erectile dysfunction can have physical causes that are worth checking, and there are established treatments such as PDE5 inhibitors.
Is tongkat ali safe?
The randomised trials have not flagged major safety problems1, but product quality matters. Testing of Malaysian products in 2006 found mercury above the legal limit in about a quarter of them.
In a 2006 analysis of 100 herbal products containing tongkat ali sold in Malaysia, 26% contained mercury at levels above the country's limit for traditional medicines4. That does not mean every product today is contaminated, but it shows why the source and testing of a supplement matter.
The 2024 systematic review also highlighted how loosely testosterone-support supplements are regulated2, so products with independent quality testing are worth looking for. Talk to a doctor before taking tongkat ali if you have a hormone-related condition, are having fertility investigations, or take regular medication.
Common questions
How long do tongkat ali trials last?
The erectile function trials pooled in one meta-analysis measured results at 12 weeks3. There is less research on shorter or much longer periods.
Is tongkat ali better than ashwagandha?
They have not been compared head to head. A systematic review of testosterone-support supplements rated both tongkat ali and ashwagandha as 'possibly effective' for healthy men2. If you have symptoms of low testosterone, a proper assessment is still the first step.
Is tongkat ali the same as longjack?
Yes. Longjack, Malaysian ginseng and Eurycoma longifolia all refer to the same plant. Check labels for the Latin name, because blended products often combine several ingredients.
Read more on this
Supplement ingredients for men’s sexual health: what the research shows
Does testosterone affect sex drive? Separating myth from mechanism
How testosterone changes after 40 (and what actually helps)
Sources
- Leisegang K, et al. 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
- Morgado A, et al. Do "testosterone boosters" really increase serum total testosterone? A systematic review. Int J Impot Res. 2024;36(4):348-364. PubMed
- Kotirum S, et al. Efficacy of Tongkat Ali (Eurycoma longifolia) on erectile function improvement: systematic review and meta-analysis of randomized controlled trials. Complement Ther Med. 2015;23:693-698. PubMed
- Ang HH, Lee KL. Contamination of mercury in tongkat Ali hitam herbal preparations. Food Chem Toxicol. 2006;44(8):1245-1250. PubMed
Not medical advice. Written by Eric Stephens from the research cited above; not reviewed by a doctor. If something worries you, see a GP.