Tribulus Terrestris Dietary Supplement
July 2000
Tribulus Terrestris:
The dietary supplements Tribestan (Sopharma, Sofia, Bulgaria), Tribulus Terrestris (Hi Tec Nutrition, Douglas, UK), etc., are preparations made from the Tribulus Terrestris plant. The active ingredients are steroid saponins, with the main component being the phytosterol protodioscin (26-O-β-D-glycopyranosyl-22-hydroxyfurost-5-ene-3β26-diol-3-O-β-diglucorhanoside).
Fig. 1: Protodioscin, the main active ingredient in Tribulus terrestris preparations, R = glucose:rhamnose (1:2)
History
According to studies, all of which took place in the late 1970s and early 1980s, Tribulus terrestris supplements are said to increase spermatogenesis and ejaculate volume when taken over the long term (e.g., by increasing the number of Sertoli cells). They are also said to increase libido in humans and animals.
Significance as a performance-enhancing drug
In the sports sector (bodybuilding and fitness scene), this product is marketed for its alleged anabolic effects. These anabolic effects are said to be based on an increase in the body’s own testosterone levels. However, the original studies in question have not been published in scientific journals but are merely documentation from a company that markets this product (Sopharma, Sofia, Bulgaria). These results should therefore be treated with caution.
The active ingredients of Tribulus Terrestris have not yet been banned as doping agents in sports by WADA. No side effects are currently known. The same applies to its performance-enhancing effects.
In principle, the use of testosterone is prohibited under WADA regulations. Furthermore, any attempt to increase the body’s own testosterone production through pharmacological agents (such as HCG) is considered a doping measure. However, the active ingredient in Tribulus Terrestris will only be banned once clear scientific data on testosterone elevation is available. The use of Tribulus Terrestris must therefore currently be regarded as a doping-like measure.
In principle, the safety of dietary supplements with regard to doping-relevant substances cannot be guaranteed, as they are not monitored like pharmaceuticals and it is known that some are adulterated or contaminated with doping-relevant substances.
