Tribulus terrestris (tribulus) is a dicotyledonous herbal plant of the Zygophyllaceae family. The plant is widely naturalised and extracts of its fruits and aerial parts have been used in ancient medicine for its diuretic, tonic and aphrodisiac properties. It was also claimed that the use of tribulus could increase the body's natural testosterone levels, and hence can improve male sexual performance and enhance muscle building potential. Here we review the scientific evidence available about the effects of tribulus on human sexual performance, testosterone levels and exercise performance.
Tribulus extracts has been shown to possess aphrodisiac effects on rats (Gauthaman et al 2002, Life Sciences). Supplementation of tribulus has been shown to significantly increase serum testosterone levels in a limited number of animal studies (Qureshi et al 2014, Journal of Dietary Supplements). One recent study found that tribulus supplementation can improve desire in women with hypoactive (not active) sexual desire disorder and may be used as a form of treatment in the future for such disorders (Raisi et al 2014, Daru). However, the use of tribulus did not appear to have any effects on male erectile dysfunction in a recent randomise, double-blind study (Santos et al 2014, Actas Urologicas Espanolas).
The effect of tribulus on testosterone levels has been debated. Even though some claimed that tribulus supplementation could increase serum testosterone levels in some animals, such effect has not been observed in humans. Evidence to date suggests that tribulus is ineffective for increasing testosterone levels in human (Qureshi et al 2014, Journal of Dietary Supplements).
Supplementation of tribulus extracts also showed no significant effects on the body composition and exercise performance in resistance-trained males compared to the placebo (Antonio et al 2000, International Journal of Sports Nutrition and Exercise Metabolism). Supplementation of tribulus over a 5-week period did not increase strength and lean muscle mass in twenty-two Australian male rugby league players (Rogerson et al 2007, Journal of Strength and Conditioning Research).
The existing scientific literature on the effects of tribulus on humans is still quite limited. Nevertheless, the data available to date indicates that the hype surrounding tribulus extracts is not warranted. To date, there is insufficient evidence to suggest that tribulus increases testosterone levels in humans. Furthermore, there is a lack of scientific evidence to suggest that it helps to improve athletic performance or to increase muscle mass. The best way to improve your performance is to through proper training, good rest and proper nutrition, there are no shorts-cuts or quick fixes.