Tribulus, also known as puncturevine, is an annual or perennial vine found in tropical and subtropical areas around the world. Considered a noxious weed in most regions, tribulus is a prostrate vine generally less than 3 centimeters in height, spreading to as much as 1.5 meters across. The plant has miniscule green leaflets (usually less than 6 millimeters long) and tiny yellow flowers. Each flower produces a fruit consisting of four hard, sharp "seeds" (actually pointed, single-seeded segments of fruit), approximately 5 millimeters from tip to tip, which are used for health purposes.
Tribulus contains several steroidal saponins, natural hormone-like compounds found in a variety of plants.
A common dosage recommendation for tribulus is 500 to 750 mg per day, but some studies have used as much as 1,500 mg per day. Tribulus has very low toxicity and appears to be safe, with no known side effects at this dosage range. Because it may alter hormonal chemistry, tribulus is not recommended for pregnant or lactating women or men with enlarged prostates.