Horny goat weed (Epimedium) is traditionally used in Chinese medicine for sexual vitality, erectile dysfunction (ED), menopausal symptoms, fatigue, and bone health, with its active compound, icariin, potentially improving blood flow and mimicking estrogen; while animal studies show promise for blood flow and heart health, evidence in humans is limited, though some research suggests it may help postmenopausal bone loss and cholesterol, often needing combination with other herbs for best effect.