Tribulus terrestris is a Mediterranean plant, also known as puncture vine. For many years, people have taken tribulus terrestris to improve athletic performance and sexual issues. It has also been used to support heart health and circulation. Studies performed in Bulgaria indicate that tribulus terrestris helps raise LH (luteinizing hormone) and testosterone levels, which may have a positive effect on sexual performance and sports performance. LH regulates testosterone production in the testes. High levels of LH go hand in hand with high testosterone levels.*