What are Tribulus terrestris?

Tribulus terrestris (commonly known as puncture vine—the bane of bicycles in areas where it grows) has a long history of traditional medical use in China, India, and Greece. It was recommended as a treatment for female infertility, impotence, and low libido in both men and women, and to aid rejuvenation after long illness. The herb became widely known in the West when medal-winning Bulgarian Olympic athletes claimed that use of tribulus had contributed to their success. However, current evidence suggests that it does not enhance sports performance.

Studies performed in Bulgaria are the primary source of most current health claims regarding tribulus. According to this research, tribulus increases levels of various hormones in the steroid family, including testosterone, DHEA, and estrogen, and for this reason improves sports performance , fertility in men and women , sexual function (again in men and women ), and symptoms of menopause (such as hot flashes). ^{1 2 3 4} 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. One well-designed study failed to find that tribulus affects male sex hormone levels in young men. ⁵ Other studies that are far too preliminary to prove...

Safety Issues

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 the herb safe both in the short and long terms. ⁶ 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. ⁷

Note: Women who are pregnant or nursing should not use any tribulus product. If the herb works as described, it might alter hormones in unsafe ways.