Tribulus terrestris

Tribulus terrestris (commonly known as puncture vine) is a tropical plant with a long history of medicinal use. It has been tried for low libido in both men and women, female infertility, and impotence. In addition, it has been studied as a treatment for heart disease.

Tribulus is widely marketed as a sports supplement and as a treatment for sexual problems, such as low libido (in both men and women) and impotence. However, there is no meaningful scientific evidence to support any of these uses. Bulgarian research is the primary source of most health claims regarding tribulus. According to this research, tribulus increases levels of various hormones in the steroid family, including testosterone, DHEA and estrogen, and improves sports performance, fertility, sexual function, and symptoms of menopause (such as hot flashes). Unfortunately, the design of these studies appears to fall far short of modern scientific standards, and there has not been any trustworthy scientific confirmation of these supposed benefits. In addition, other studies that are far too preliminary to prove anything at all are widely quoted as proving that tribulus is helpful for the treatment of angina, impotence, high cholesterol, diabetes and muscle spasms, and for the prevention of kidney stones. One non-Bulgarian study compared the effects of tribulus (3.21 mg per kilogram of body weight—for example, 292 mg daily for a 200-lb man) against placebo on body composition and endurance among 15 men engaged in resistance training. At the end of the 8-week study, the only significant difference between the treatment and placebo groups was that the placebo group showed greater gains in endurance.

Tribulus terrestris is usually taken at a dose ranging from about 85 to 250 mg 3 times daily with meals. Some tribulus products are standardized to provide 40% furostanol saponins and taken at a dose providing 115 mg of saponins 2 to 3 times daily.

No significant adverse effects have been noted in any of the clinical trials or human research studies of tribulus. Animal studies performed in Bulgaria are said to have found tribulus safe both in the short and long terms. However, it is not clear whether these studies were performed in such a way that their conclusions can be trusted. Tribulus is known to have a toxic effect on sheep. Note: Women who are pregnant or nursing should not use any tribulus product, because if it works as described it might alter hormones in unsafe ways.