Eastern Europeans know something about underground performance supplements. Think of androstenedione, for example. For over thirty years, one of their best kept secrets has been a seemingly innocent herb called Tribulus terrestris L. Found natively in Bulgaria, this peculiar herb contains some interesting phytochemicals that can benefit any bodybuilder or competitive athlete. What are these phytochemicals? Steroidal saponins. These steroidal saponins found in tribulus have been used by the world-class Bulgarian powerlifting team for record lifts. In fact, studies performed in Europe found that tribulus use could increase testosterones production by 30% or more in only five days. Researchers believe that the steroidal saponins in tribulus might have a stimulating effect on luteinizing hormone LH , a gonad-stimulating hormone which can positively affect testosterone production. For every possible competitive edge, use Tribulus Pro.