Tribulus Terrestris Extract is a natural herbal supplement that may help increase levels of testosterone by increasing the body's production of luteinizing hormone (LH) levels. LH is produced by the pituitary gland and plays an important role in triggering natural testosterone production. Tribulus Terrestris Extract first gained recognition because of its use by one of the more successful Bulgarian weight lifting teams. Tribulus terrestris is a testosterone enhancer that may promote improved muscle growth and overall body strength. It enhances the production of the luteinizing hormone (LH). When LH levels are increased, the natural production of testosterone is also increased. LH is a hormone that also enhances sex drive and libido. Plus, studies have reported no toxicity or side effects.