What is Horny Goat Weed (Epimedium Sagittatum)? Xialis Rx Horny Goat Weedis a hardy perennial reported to possess aphrodisiac qualities. This affect was allegedly discovered by a Chinese goatherd who noticed sexual intercourse in his flock after they ate the weed. wont to restore concupiscence in both men and ladies , this supplement stimulates sensory nerves and helps restore low levels of both thyroid and testosterone hormone back to normal. Horny Goat Weed has been wont to treat impotence, increases sperm production and enlarges the penis.