Tribulus terrestris is a flowering plant in the family Zygophyllaceae, native to warm temperate and tropical regions of the Old World in southern Europe, southern Asia, throughout Africa, and in northern Australia. It can thrive even in desert climates and poor soil. Like many weedy species, this plant has many common names, including puncturevine, caltrop, cathead, yellow vine, goathead, and burra gokharu.
http://en.wikipedia.org/wiki/Tribulus_terrestris#Dietary_supplement
T. terrestris is now being promoted as a booster for the purpose of increasing sex drive. Its use for this purpose originated in Eastern Europe in the 1970s. It was popularized in America by 1970s strongman Jeffrey Petermann. Independent studies [5] have suggested that Tribulus terrestris extract slightly increases hormone levels, though leaving them in the normal range.
The extract is claimed to increase the body's natural testosterone levels and thereby improve male sexual performance and help build muscle. T. terrestris has consistently failed to increase testosterone levels in controlled studies.[6][7][8] It has also failed to demonstrate strength-enhancing properties.[9] However, many supplement brands have sold products that combine various herbs with T. terrestris, with debatable effects.
Tribulus has been shown to enhance sexual behaviour in an animal model.[10] It appears to do so by stimulating androgen receptors in the brain.
Some body builders use T. terrestris as post cycle therapy or "PCT". After they have completed an anabolic-steroid cycle, they use it under the assumption that it will restore the body's natural testosterone levels.
