According to legend, a goat herder noticed increased libido in his herd after they consumed a plant that came to be called horny goat weed. Also known as epimedium, it’s been used as an aphrodisiac for centuries by the Chinese. Some also consider it a treatment option for menopause. Horny goat weed is sold as a health supplement, in raw form or as a tablet or capsule. The amount of time it takes to work is difficult to determine, but it’s believed to induce the desired effect in as little as 30 to 90 minutes. Some sources claim the effects can last as long as a week.


Recommended dosage of horny goat weed is approximately 500 milligrams per capsule. Typically these products are standardized with 10% icariin, the active ingredient. The suggested daily intake is two to four capsules.


Animal studies reviewed by’s medical board show horny goat weed may increase nitric oxide levels, which relaxes smooth muscle tissue and facilitates blood flow to the penis or clitoris. It appears to inhibit the PDE-5 enzyme, similar to the way Viagra works. There is evidence that horny goat weed may be able to restore balance of cortisol, testosterone, and thyroid hormones.

Lengthy clinical trials are needed before “compound 5” can be approved as a viable drug. This may keep the compound off the marketplace for as long as another 10 years. Meanwhile, University of Milan researchers concluded that while there may be some benefit to consuming horny goat weed, it’s not as effective as Viagra.


Animal studies indicate that higher doses of the compound icariin can be toxic to the liver and kidneys. No significant drug interactions have been noted.

References and Resources Horny Goat Weed Facts