Interest in Tongkat Ali (Eurycoma longifolia) is backed by a growing body of research. The evidence is still developing — most studies are small and short — but several are worth knowing. Here's a balanced summary.
Focus: the ergogenic (performance-related) effects of Eurycoma longifolia during resistance training.
In this small pilot study, men following a five-week supervised strength-training programme while taking Eurycoma longifolia extract showed significant increases in lean body mass and one-rep-max strength compared with their starting point.
Hamzah S, Yusof A. The ergogenic effect of Eurycoma longifolia Jack: a pilot study. British Journal of Sports Medicine 2003;37(5):464–470. — find it on Google Scholar
Worth noting: this was a small, early pilot study (around a dozen participants). It's encouraging context, not proof of a guaranteed effect.
Focus: the effect of a standardised Tongkat Ali extract on stress hormones and mood in moderately stressed adults.
Daily supplementation with a low dose of standardised root extract was associated with improvements in measures of the cortisol-to-testosterone ratio and self-reported mood, with reported increases in salivary testosterone versus placebo. Read the study on PubMed Central
Worth noting: the study used salivary (not serum) measures and a modest sample. Mood and stress findings are self-reported.
Taken together, the research is promising but early. Studies vary in size, dose, extract type and how they measure outcomes, so results don't always transfer neatly to everyday use. The honest summary: there's enough here to explain the interest in Tongkat Ali, but not enough to make medical promises — and we don't.
Research summaries are provided for information only and do not constitute health claims or medical advice. Tongkat Ali is a food supplement and is not intended to diagnose, treat, cure or prevent any disease.
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