Evidence Level
Insufficient
Tribulus terrestris is a cautionary tale in supplement science. Heavily marketed based on animal studies and Eastern European sports doping lore, it was one of the best-selling "testosterone boosters" for decades. However, well-controlled human studies consistently fail to show any testosterone elevation. Neychev & Mitev (2005) found no change in testosterone, LH, or FSH in young men. Rogerson et al. (2007) found no effect on body composition or strength in trained athletes. The small libido benefits that some users report likely involve non-hormonal mechanisms. For anyone seeking evidence-based testosterone optimization, focus on sleep, resistance training, body composition, vitamin D, and zinc status.