Supplement analysis backed by scientific evidence · PT

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Moderate evidenceMen's health

Tongkat Ali

Tongkat ali is the one testosterone-booster herb with a positive meta-analysis behind it, though the effect is clearest in older or hypogonadal men rather than healthy young ones. Trial quality is mixed and extract standardisation varies widely, so treat the effect size with caution.

What the science says

  • Raising serum total testosterone Moderate evidence

    A 2022 systematic review and meta-analysis of clinical trials found Eurycoma longifolia significantly increased serum total testosterone in men, with the effect most consistent in participants who were older or had low baseline testosterone. Trials in eugonadal young men are more often null, so it behaves like a restorative rather than a booster.

  • Erectile function and sexual wellbeing Moderate evidence

    A 6-month double-blind placebo-controlled RCT in men with androgen deficiency of the aging male used 200 mg/day alongside concurrent training and reported improvements in erectile function and testosterone levels. Several other 12-week trials at 200-300 mg/day report improved sexual function and quality-of-life scores in aging men, though several were manufacturer-supported.

  • Stress, cortisol and mood Limited evidence

    A small trial in moderately stressed adults reported reduced salivary cortisol and improved tension and confusion scores at 200 mg/day for 4 weeks. This finding is quoted constantly but has not been replicated in adequately powered trials.

  • Strength, power and body composition Limited evidence

    Trials combining tongkat ali with resistance training report inconsistent effects on strength and lean mass, and where testosterone rises the change is usually too small to plausibly drive body composition change. Do not expect gym results from it.

Dosage & safety

Studied dose200-400 mg/day of a standardised hot-water root extract (trials most often use material standardised to eurycomanone and glycosaponin content), taken for 4 weeks up to 6 months. Crude root powder doses are much higher and not comparable.
SafetyGenerally well tolerated at trial doses; reported effects include insomnia, restlessness, irritability and mild GI upset. Heavy metal contamination, particularly mercury and lead, has been documented in tongkat ali products, so third-party tested material matters. Because it may raise testosterone, avoid in prostate cancer, hormone-sensitive conditions, and in pregnancy or breastfeeding. It may add to the effect of antihypertensive and antidiabetic medication, and animal data suggest a possible interaction with propranolol. Not currently prohibited by WADA, but athletes should note that testosterone-active herbals can complicate a steroid profile.

Scientific references

Where to buy

Nutricost, Tongkat Ali, 120 Capsules

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