Testosterone is the hormone responsible for the development and maintenance of secondary sex characteristics in males. High levels of the hormone increase sexual desire as well as competitive and even aggressive behavior. Increasing testosterone levels in men with low sperm counts can improve their fertility. Herbalists claim that several supplements can increase testosterone levels; research supports only some of these claims.
Mucuna pruriens
Mucuna pruriens--also known as cowitch and velvet bean--has been used as an aphrodisiac for centuries. Its tendency to increase libido led people to believe that it increases testosterone levels in men. A 2008 study in the journal of Fertility and Sterility by Shukla, et al. proved this to be the case. In the study, the researchers treated men with low fertility with the extract from Mucuna pruriens. They found that treatment with the herb "significantly improved serum testosterone, luteinizing hormone, dopamine, adrenaline and noradrenaline levels in infertile men." The increased hormone levels resulted in higher sperm counts and improved fertility.
Eurycoma longifolia
Eurycoma longifolia--also known as Tongkat Ali--grows in the tropical areas of southeast Asia. It is a small evergreen tree that has for centuries been used in traditional medicine. Locals use it principally as an aphrodisiac. The herb contains a bioactive peptide that has been shown to increase testosterone levels in humans and animals, according to Dr. Rha from the Massachusetts Institute of Technology. The peptide has been isolated and patented for commercial development and distribution.
Epimedium grandiflorum
Epimedium grandiflorum is another Asian herb that is famously associated with improving sexual problems, such as decreased libido and fertility, in both men and women. Locals call the herb "horny goat weed" because they claim that goats that graze on it tend to engage in sexual activity immediately after. People take E. grandiflorum to treat symptoms of menopause and sexual dysfunction. This led to the belief that the herb adjusts hormone levels in people who take it. However, no scientific evidence exists to support the idea that the consumption of E. grandiflorum increases testosterone levels in men, according to the New York University Medical Center. The data do not directly contradict the notion of increased testosterone, though, so more research must be done to be determine the truth.
