* Premium Extract * Sexual Tonic * 10% Icariin * Dietary Supplement Did You Know? Horny Goat Weed originates in China where it is called yin yang huo because it is a tonic for the female (yin) and the male (yang). Health & longevity through the healing power of nature—that"s what it means to Trust the Leaf. Horny Goat Weed (Epimedium sagittatum) is standardized to 10% icariin. Horny Goat Weed is a traditional Chinese tonic for healthy sexual activity. Our Horny Goat Weed extract is carefully tested and produced to certified quality standards.