Longjack extract for increasing testosterone Original paper

Eurycoma longifolia (commonly known as longjack, Malaysian ginseng, and tongkat ali) is a herb that has traditionally been used as an aphrodisiac in Southeast Asia. Although longjack is often marketed as a testosterone booster, trials examining the effect of longjack extract on testosterone levels in humans have yielded mixed results.

This meta-analysis of 5 randomized controlled trials examined the effect of supplementation with longjack extract, compared to placebo, on testosterone levels in a total of 286 men. The researchers performed subgroup analyses based on the health status of the participants (with or without hypogonadism).

Of the 5 trials, 4 used a standardized freeze-dried water extract of longjack (Physta®, Biotropics). The daily dose ranged from 100 to 600 mg. The intervention duration ranged from 2 weeks to 6 months.

Compared to placebo, supplementation with longjack extract increased testosterone levels in the overall analysis (standardized mean difference of 1.35), as well as in the subgroups of men without hypogonadism (standardized mean difference of 0.76) and men with hypogonadism (standardized mean difference of 1.86).

Of the 5 trials, 1 had a high risk of bias, 2 had some methodological concerns, and 2 had a low risk of bias.

Because the results were based on only a few small trials, most of which were of low or unclear methodological quality, we should consider the findings preliminary.