Tribulus terrestris
Tribulus is a source of steroidal saponins such as protodioscin. Tribulus allegedly increases testosterone via stimulation of the pituitary gland to produce luteinizing hormone (LH), which, in turn, acts on the testes. This claim is based on older Bulgarian research that has not been replicated in the West. Although it’s known to raise testosterone in animals, recent studies on humans have shown that Tribulus has no significant effects on testosterone or LH levels, body composition, or exercise performance.
See Paul’s Tribulus review for more information.
