Does tongkat ali actually work for your testosterone?

Of all the herbal supplements marketed as testosterone boosters, tongkat ali has one of the better foundations of evidence. A meta-analysis of five randomised trials found a statistically significant increase in total testosterone in men, both in healthy men and in men with low testosterone production due to age. The effect size was moderate, but the absolute increase in measurable values was not reported consistently across studies.

In men with age-related low testosterone, the results are striking: a clinical study of 76 men found that the proportion with a normal testosterone level rose from 35 to 91 percent after one month on a daily dose of 200 mg. That study had no placebo group, however, so a placebo effect cannot be ruled out. A six-month placebo-controlled trial in men with a similar problem found the greatest improvement in the group that combined tongkat ali with strength training, although the effect of tongkat ali alone was difficult to isolate within that design.

For context, a broad systematic review of 27 different testosterone supplements concludes that most provide no evidence of benefit. Tongkat ali is rated as 'possibly effective', which is relatively more favourable than tribulus or maca, but slightly less consistent than ashwagandha or mucuna in specific patient groups.

The picture on safety is still incomplete. No serious adverse effects have been reported to date at therapeutic dosages. Long-term human data are entirely lacking, however. Anyone buying tongkat ali as an off-the-shelf supplement should be aware that the complete product has never been tested as such in a randomised trial: 68% of the ingredients in such products have weak or contradictory evidence, and tongkat ali itself does not resolve that problem.