Tongkat ali has better human data than most testosterone herbs, but the trials are small, mostly use one branded extract, and are often industry-linked. Here's what they actually found.
Tongkat ali (Eurycoma longifolia) has modest evidence for raising testosterone, mainly in men whose levels start low. A 2022 meta-analysis of five small trials (232 men) found a significant rise overall, but the increase in men with normal levels wasn't statistically significant. Most studies used 100 to 600 mg a day of a standardized water extract, and the evidence is still limited.
Tongkat ali is the root of Eurycoma longifolia, a shrub native to Southeast Asia. It's also sold as longjack or Malaysian ginseng. In traditional use it was taken for low energy and libido, and today it's one of the most common ingredients in testosterone booster formulas.
Most of the human research uses a standardized hot-water root extract rather than raw powder. One branded extract, Physta, appears in the majority of trials. It's standardized to a range of eurycomanone, one of the plant's marker compounds. That matters, because results from a tested extract don't automatically apply to a cheap capsule of ground root.
The best summary so far is a 2022 systematic review and meta-analysis published in Medicina. The authors found nine relevant human studies and pooled five randomized controlled trials covering 232 men. Doses ranged from 100 to 600 mg a day, and study length from 3 days to 6 months.
Overall, tongkat ali significantly increased total testosterone compared with the control groups. The pattern underneath that headline result is the useful part:
The authors concluded the herb looks promising, particularly for men with low levels, but said more research is needed before it can be recommended clinically.
One of the larger individual trials, published in 2021 in Food & Nutrition Research, enrolled 105 men aged 50 to 70 with testosterone below 300 ng/dL. They took 100 mg or 200 mg of Physta, or a placebo, daily for 12 weeks.
Two of the authors worked for Biotropics Malaysia, the company behind Physta. That doesn't make the results wrong, but it's a reason to want independent replication.
A 2013 trial in the Journal of the International Society of Sports Nutrition gave 200 mg a day of the same extract, or placebo, to 63 moderately stressed adults (32 men, 31 women) for four weeks. Compared with placebo, the tongkat ali group had 16% lower cortisol and 37% higher testosterone, plus small improvements in tension, anger and confusion scores. Depression, vigor and fatigue scores didn't differ between groups.
This study was funded by Biotropics Malaysia, and several authors had commercial ties to the extract. It was also short and small.
Better than for most herbal testosterone ingredients, but still limited. The meta-analysis authors flagged several problems themselves:
So a fair reading is this: tongkat ali probably produces a modest rise in testosterone in men whose levels start low, and the effect in men with normal levels is uncertain. That's roughly where the evidence for fenugreek and testosterone sits too: real signals, small studies.
The human studies used 100 to 600 mg a day of standardized water extract, with 200 to 400 mg a common range. There's no official recommended dose, and more hasn't been shown to work better.
Quality is a genuine concern. The meta-analysis cites testing of 24 Malaysian products containing eurycomanone in which only 11 met the recommended level. A separate study reported mercury contamination in some tongkat ali preparations. If you buy it, look for:
Our guide on how to choose a testosterone supplement walks through how to check labels and doses against the research.
In the trials, tongkat ali was generally well tolerated over periods of up to a few months. The meta-analysis notes that one study reported stomach upset and itching, and in another, adverse events occurred in both the treatment and placebo groups. Long-term safety hasn't been studied.
Talk to your doctor before taking it, and avoid it unless they agree, if you:
Also be aware that the FDA doesn't approve supplements before sale, and some sexual-performance and "testosterone" products have been found to contain undeclared prescription drugs. Buying from a reputable, tested brand reduces that risk.
Tongkat ali makes most sense for a man with borderline-low testosterone or stress-related fatigue who wants to try a supplement with some human data behind it, after ruling out bigger causes. If you haven't been tested, start there. Our guide to low testosterone symptoms in men covers what testing involves and the common, fixable causes like weight, sleep apnea and medications.
It's not a substitute for treatment if you have clinical hypogonadism, and it isn't likely to do much for a young man whose testosterone is already normal.
Tongkat ali is one of the better-studied herbal testosterone ingredients, and the trials point to a modest increase, mostly in men whose levels start low. But the evidence comes from a handful of small, often company-linked studies of one extract, with signs of publication bias. If you try it, use a standardized extract at 200 to 400 mg a day, buy third-party tested, check with your doctor if you have a prostate condition or take hormone-related drugs, and judge it on a follow-up blood test rather than how you feel in week one.