Icariin/ Horny Goat Weed/ Epimedium Chemical Name: EPIMEDIUM BRM (HORNY GOAT WEED) Appearance: Brown powder Functions:Icariin, a flavonol glycoside, is an interesting substance found in certain herbs, particularly horny goat weed. known as the botanical name epimedium. Icariin has been studied as a substance that dilates blood vessels and can potentially be helpful in the treatment of erectile dysfunction. Icariin has been found to have phosphodiesterase type 5 inhibitor activity.