<body><h1>Tribulus Terrestris</h1><p> syn. puncturevine</p><p> syn. Bai Ji Li</p><p> </p><p> <div id=’imgblock’><img data-pointer=’9123’/></div></p><h2> Description: </h2><p> Tribulus terrestris is an herbal plant native to many temperate regions of the world. It has a history of use in traditional Chinese and Indian (Ayurvedic) medicine that dates back centuries. Tribulus terrestris has also been widely used in Eastern Europe, and in the early 1980’s was introduced as a medicinal product in Bulgaria. Tribulus is mainly applied as an aphrodisiac, to treat erectile dysfunction, and as a general tonic for improving vitality and energy in older men. More recently, extracts of this plant have been popularly marketed to bodybuilders, claiming that the herb can increase testosterone levels and facilitate the anabolic effects of this hormone.</p><p> </p><p> Modern studies with animals do confirm libido stimulating and erection supporting properties of this traditional herbal medicine.508,509 The exact mechanism that imparts such action, however, remains unclear. Studies on several animal species have demonstrated a notable ability to increase serum androgen (testosterone, DHT) levels.510 Thus far, however, human studies have failed to demonstrate the same. Whether this is due to individual variances, study methodological difficulties, or a true absence of consistent hormone elevating effect remains unclear. Further study is needed to determine what, if any, influence tribulus terrestris has over human male androgenicity. It is also presently unknown if tribulus terrestris extract has tangible ergogenic value.</p><p> The main biologically active component in tribulus terrestris is believed to be a steroidal saponin named protodioscin. Numerous additional saponins have also been identified in this plant, however, including prototribestin, pseudoprotodioscin, dioscin, tribestin, and tribulosin.511 Steroidal saponins share the basic 4-carbon ring skeleton of all steroids, but not necessarily inherent androgen-, estrogen-, cortisol-, or progesterone-like activity. A full understanding of each saponin has not been achieved, and thus the activity of tribulus remains the subject of much speculation. Sport supplements containing tribulus terrestris extract are typically standardized for protodioscin or total steroidal saponin content.</p><h2> Promoted Benefits:</h2><p> Tribulus terrestris extract is promoted to increase testosterone levels, and support muscle mass and strength gains. </p><p> </p><p> Clinical Studies: </p><p> </p><p> The use of tribulus terrestris as a sport supplement is supported by animal data only. Its Clinical Support Rating is 2 (2/5).</p><p> </p><p> Data provided from Sopharma, the Bulgarian manufacturer of medicinal tribulus terrestris (Tribeston), is widely referenced to demonstrate the testosterone elevating properties of this plant extract. This internal study ostensibly demonstrates a weak but positive effect on male hormones.512 This study, however, was not placebo-controlled nor independently reviewed and published. It therefore cannot be accepted as clinical validation. </p><p> </p><p> The most commonly cited independent study demonstrating a positive effect on anabolic hormone levels involved the administration of various doses (2.5-30 mg/kg of body weight) of the extract orally or intravenously to rabbits, rats, and primates.513 The administration period lasted for up to eight weeks. All animals noticed increases in androgen levels (testosterone, DHT) ranging from 25-52%. The increase in rats was 25% after oral doses of 5 mg/kg of body weight. </p><p> </p><p> A placebo-controlled study with a group of healthy young men failed to find a similar increase in serum testosterone levels.514 It involved administering tribulus terrestris extract at a dose of 10 mg/kg or 20 mg/kg of body weight daily for a period of four weeks. Hormonal measures were taken at various points during the experiment. The study did not find any statistically significant effect of tribulus terrestris on serum androgen levels. </p><p> </p><p> An additional placebo-controlled study examined the effects of tribulus terrestris extract on muscle strength and body composition in a group of elite rugby players.515 Subjects consumed 450 mg per day of the extract during a five-week period of intense resistance training. The study found no difference between the supplement and placebo groups with regard to body composition (lean body mass) or strength.</p><p> </p><p> Another placebo-controlled study was conducted with a group of resistance-trained men.516 Subjects consumed 3.21 mg/kg of body weight of tribulus terrestris extract daily for eight weeks, and underwent a controlled resistance training program. The study demonstrated no changes in muscle mass, strength, total body water, or calorie intake as a result of tribulus terrestris supplementation. </p><p> Further research is needed to determine if tribulus terrestris can be used to increase male androgen levels, and if there is any ergogenic value to its application by athletic individuals.</p><h2> Empirical Evidence: </h2><p> Tribulus terrestris extract has been widely used as a stand-alone supplement. The feedback on this supplement has been somewhat positive. A good percentage of users report subjective feelings of increased androgenicity (increased vitality, energy, libido, and training aggressiveness). Some are even able to associate this with a tangible increase in muscle mass and strength. Such strong results, however, are very inconsistent. A fair percentage of users are unable to attribute any specific benefit to tribulus supplementation, and often report its use is without merit. Tribulus terrestris extract has an Empirical Evidence Rating of 4 (4/5).</p><p> </p><h2> Effective Dosage: </h2><p> An effective dosage of this supplement has not been established. Manufacturers commonly recommend 500-1,500 mg per day. </p><h2> Side Effects / Safety: </h2><p> Tribulus terrestris extract was well tolerated during all clinical studies, with no significant side effects.</p><p> </p><p> </p></body>
