Horny goat weed is a Chinese herbal remedy made from Epimedium plants. People take it to support libido and sexual function in both men and women. The active compound icariin blocks PDE5, much like certain prescription drugs. Many use it 30 to 60 minutes before sex, while others take it daily as a general supplement.
Horny goat weed can lower blood pressure and may interact with blood thinners, blood pressure drugs, and nitrates. Do not take it with PDE5 inhibitor medications like sildenafil. Avoid during pregnancy and breastfeeding.