Tongkat ali, a medicinal herb with the scientific name, Eurycoma longifolia Jack, is a popular herbal supplement with many purported benefits. According to the British Journal of Sports Medicine, the active constituents of tongkat ali appear to be eurycomalacton, eurycomanon, and eurycomanol. Scientific studies into the active chemical components of tongkat ali have revealed several possible uses for the herb, namely, as an aphrodisiac, ergogenic aid and cancer-fighting agent.
One of the purported uses of tongkat ali is as an ergogenic aid, or a supplement that enhances the body's adaptive response to exercise. Tongkat Ali is thought to produce this effect by causing an increase in the body's levels of testosterone, a male sex hormone which effects muscle size and performance. According to a 2003 study by S. Hamzah and A. Yusof in "The British Journal of Sports Medicine," a tongkat ali extract in conjunction with a weight-training program, caused an increase in lean body mass and a loss of fat tissue relative to placebo. This supports the use of tongkat ali by athletes as an ergogenic aid.
As tongkat ali is thought to increase levels of the male sex hormone testosterone, it may have utility as a libido-enhancer or general male sexual aid. According to a 2003 study by Ang HH, Ngai TH and Tan TH in "The Journal of Phytomedicine," when an extract of tongkat ali was administered to middle-aged rats their sexual performance increased relative to the placebo group. The main effect observed was a decrease in the hesitation-time of the rats, indicating an increased libido.
Tongkat ali has also been studied as a possible cancer-fighting agent, as several of it's chemical constituents have been shown to exert anti-cancer effects in studies. According to a 2005 study by Tee TT and Azimahtol HL in the journal, "Anticancer Research," an extract of tongkat ali exerted anti-proliferative effects against human breast cancer cells. In a 2003 study conducted at National Cheng Kung University and published in "The Journal of Natural Products," an extract of tongkat ali killed human lung cancer cells, as well as demonstrating anti-malarial effects.