Tribulus terrestris has been used for centuries in ancient Greece, India and Africa to enhance vitality and virility. Recent research indicates that Tribulus can support the body’s free radical defense systems and preliminary studies suggest that Tribulus may help to promote healthy endocrine function and male reproductive health. Protodioscin is a phytochemical agent derived from Tribulus terrestris L plant, which has been clinically proven to improve sexual desire and enhance erection via the conversion of protodioscine to DHEA (De-Hydro-Epi-Androsterone). NOW® Tribulus 400 mg capsules is standardized to contain a minimum of 45% Saponins to deliver consistent and reliable results.