Tribulus terrestris
Sold as a testosterone booster in bodybuilding, but several trials in young men or trained athletes show no increase in testosterone or strength gains. Other literature on sexual function in men and women tells a different story.
Benefits
- In premenopausal and postmenopausal women suffering from hypoactive sexual desire disorder, significantly improves the female sexual function score (desire, arousal, lubrication) compared to placebo, in four double-blind randomized trials of 90 to 120 days bringing together 40 to 67 participants each
- In 180 men suffering from mild to moderate erectile dysfunction, 750 mg per day for 12 weeks significantly improve the erectile function score and sexual desire compared to placebo, with no serious adverse effect
- In 70 elderly men with late-onset hypogonadism and erectile dysfunction, 3 months of treatment significantly raise total testosterone and improve sexual function, without worsening associated urinary disorders
Precautions
Sold for testosterone, Tribulus terrestris does not increase it in healthy young men: 4 weeks of supplementation do not modify testosterone, androstenedione or LH in 21 men (2005). In trained athletes, it also does not change strength or body composition: no difference from placebo on weight or fat mass after 8 weeks (15 men, 2000), nor on strength and lean mass after 5 weeks in 22 elite rugby players (2007) — where the urinary testosterone/epitestosterone ratio also remains unchanged, thus carrying no risk of a positive doping test. Two trials in CrossFit athletes (30 participants each, 6 weeks, 770 mg/day) also show no significant improvement in performance, body composition or inflammation markers. In 30 men over 40 years old, erectile function improves just as much with Tribulus as with placebo after 30 days: no significant difference between the two groups. A 2016 systematic review moreover concludes that evidence for an androgenic effect remains inconclusive. The hormonal signal is sometimes even reversed: in women treated for 90 days, DHEA increases but total and free testosterone decrease. The safety profile is generally good in trials, with mostly digestive adverse effects. Medical advice is necessary in the event of ongoing hormone therapy or diagnosed hypogonadism, one of the rare populations where an effect on testosterone has precisely been measured.
Recommended dosage
Trials showing an effect on sexual function most often use 750 mg per day (250 mg three times a day), over durations of 90 to 120 days for women and 12 weeks for men with erectile dysfunction — one trial in hypogonadal elderly men lasted up to 3 months. Trials finding no effect on testosterone or strength used 450 to 800 mg per day for only 4 to 8 weeks: duration matters at least as much as dose.
Did you know?
Contrary to claims, Tribulus terrestris does not increase testosterone levels or muscle mass in healthy young men or trained athletes.
What the studies say
Cette étude a examiné l'effet de l'extrait de Tribulus terrestris sur le métabolisme des androgènes chez 21 jeunes hommes en bonne santé. Après 4 semaines de supplémentation, aucune différence significative n'a été observée dans les niveaux sériques de testostérone, d'androstènedione ou de l'hormone lutéinisante par rapport au groupe placebo. Les résultats suggèrent que le Tribulus terrestris ne possède pas de propriétés augmentant les androgènes chez ces participants.
Neychev VK, Mitev VI. — Journal of ethnopharmacology (2005) — View the source study
For information only: not a substitute for medical advice. Dietary supplements are not a replacement for a varied, balanced diet. Learn more