Shindel, A. W., Xin, Z.-C., Lin, G., Fandel, T. M., Huang, Y.-C., Banie, L., … Lue, T. F. (2010, February 5). Erectogenic and neurotrophic effects of icariin, a purified extract of horny goat weed (Epimedium spp.) in vitro and in vivo. The Journal of Sexual Medicine, 7(4), 1518-1528. Retrieved from http://onlinelibrary.wiley.com/doi/10.1111/j.1743-6109.2009.01699.x/full
Wild oats: a study in 1986 by the Institute for Advanced Study of Sexuality in San Francisco reported effects like heightened sexual awareness, increased sexual thoughts, more orgasms (36% in men and 29% in women) and some male subjects showed increased levels of testosterone attributed to unbinding of testosterone from TBG. Oats supply steroidal saponins which modulate hormonal balance (5).
The Science: Some studies have implied that feeding maca to domestic cattle increases sperm production, but there is very little data about any sexual effect on humans. One very small randomized double-bind trial of men with erectile dysfunction found that men taking maca extract reported a small increase in their ability to get erections. But so did the control group. As with the fenugreek study, a similar study with a larger group of people is needed to see whether any differences between the controls and the maca-eaters are real.
Despite the name, horny goat weed actually helps improve your erection, not libido. Botanically known as epimedium, this herb has been used by the Chinese for centuries to treat, among other things, low libido and erectile dysfunction. “A growing body of research shows that isolated icariin—the extract of epimedium—inhibits the enzyme phosphodiesterase-5 (PDE-5) and significantly increases nitric oxide synthase, helping to improve erectile function,” says Fisch. In fact, this is the same mechanism that Viagra works through (but the herb comes with a way better name).
There is no single cause for erectile dysfunction. Achieving an erection involves a complex series of physiological events; in order for an erection to occur, the body is required to coordinate nervous system responses with tactile sensations, emotional triggers, and signals from certain hormones. If any of these events are disrupted, impotence is likely to occur.
Impotence, also called erectile dysfunction (ED), can be a very frustrating problem. Some men are able to achieve an erection but are not able to maintain one. Others are not able to achieve one at all. Causes of impotence can be both physiological (affecting mostly the body and organs) or psychological (affecting the mind). Luckily, there are natural remedies for impotence you can try.
Yohimbine. This chemical is found in the bark of an African tree called yohimbe. It has been used as a male aphrodisiac in Africa, and under medical supervision it has been used as a prescription drug to treat ED. Supplements made from yohimbe bark are also available without a prescription, but they can be life-threatening if used at high doses, according to the Natural Medicines Comprehensive Database. The supplement can interact in a harmful way with certain drugs, such as blood pressure medications, and should be avoided by anyone with liver, kidney, heart, or diabetes problems or problems with anxiety or depression. Like DHEA, yohimbine should not be taken without a doctor's supervision.
Many stores sell herbal supplements and health foods that claim to have sexual potency and fewer side effects. They’re also often cheaper than prescribed medications. But these options have little scientific research to back up the claims, and there’s no uniform method on testing their effectiveness. Most results from human trials rely on self-evaluation, which can be subjective and difficult to interpret.