Horny goat weed is an ornamental plant that also has a long history of traditional use in Chinese herbalism. In China, horny goat weed is called yin yang huo because it is a tonic for the female (yin) and the male (yang). Epimedium was thought to "tonify life's gate" - a term used to refer to the "vital energy" in men. NOW® Horny Goat Weed Extract is combined with maca, another herb known for its tonifying properties.* Natural color variation may occur in this product.