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Tribulus Terrestris

Tribulus is one of the most popular testosterone boosters and one of the least supported: controlled trials in healthy men consistently show no increase in testosterone, strength or lean mass. There is weak, inconsistent evidence for improved erectile function, which appears unrelated to any hormonal effect.

What the science says

  • Raising testosterone Limited evidence

    A 2025 systematic review of clinical trials found Tribulus did not produce consistent increases in serum testosterone in men, and an evidence-based analysis of ingredients in popular testosterone and erectile dysfunction supplements placed Tribulus among the ingredients with little or no supporting human data. Multiple RCTs in trained men at 450-1500 mg/day for 4-8 weeks report no change in total or free testosterone.

  • Erectile function and libido Limited evidence

    Some trials at 750-1500 mg/day for around 12 weeks report improvements in IIEF scores in men with mild-to-moderate erectile dysfunction, but the trials are small, inconsistently standardised, and not reliably replicated. Any benefit appears unrelated to testosterone and may reflect nitric oxide-mediated effects of protodioscin.

  • Strength, power and body composition Limited evidence

    Randomised trials in resistance-trained and CrossFit athletes have repeatedly found no advantage over placebo for 1RM strength, body fat or lean mass after 4-8 weeks. If you are buying Tribulus for the gym, the trial data say it does not work.

  • Female sexual function Limited evidence

    A small number of trials in women with hypoactive sexual desire disorder report improved desire scores, but the systematic review of this literature rated the evidence as very low certainty due to small samples and high risk of bias.

Dosage & safety

Studied doseTrials have used 250-1500 mg/day of extract standardised to roughly 45-60% saponins (or to a specified protodioscin content), usually in 2-3 divided doses for 4-12 weeks. Because saponin content varies enormously between products, milligram doses are not comparable across brands.
SafetyUsually mild: GI upset, cramping, insomnia. More seriously, there are published case reports of acute hepatotoxicity and nephrotoxicity, including severe hepatorenal injury in a young man taking Tribulus, and reports of gynecomastia. Tribulus may lower blood glucose, so watch for additive effects with diabetes medication, and it may have mild diuretic and antihypertensive activity. Avoid in pregnancy (uterine stimulant in animal work) and in prostate cancer. Not prohibited in sport, but products marketed as testosterone boosters have a poor contamination record and have been linked to positive doping tests.

Scientific references

Where to buy

Swanson Vitamins, Tribulus Terrestris Extract, 500 mg, 60 Capsules

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