Tribulus is a genus of plants found in many warm regions. The best-known member is T. terrestris (puncture vine), a widespread weed and also the source of a dietary supplement 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. It has also failed to demonstrate strength-enhancing properties. However, many supplement brands such as 4Ever Fit and InterACTIVE Nutrition sold products that combines various herbs with tribulus terrestis, which has been a debate whether the effects are true or false.
Tribulus has been shown to enhance sexual behaviour in an animal model. It appears to do so by stimulating androgen receptors in the brain.
Tribulus species are perennial, but some grow as annuals in colder climates. The leaves are opposite and compound. The flowers are perfect (hermaphroditic) and insect-pollinated, with fivefold symmetry. The ovary is divided into locules that are in turn divided by "false septa" (the latter distinguish Tribulus from other members of its family).
Some body builders use T. terrestris as post cycle therapy or "PCT". After they've completed an anabolic-steroid cycle, they use it under the assumption that it will restore the body's natural testosterone levels.
Tribulus has a long history of use in the Ayurvedic and Unani systems of India. It is considered an aphrodisiac, diuretic, and nervine.