Herb library · Herb · Epimedium species, including E. sagittatum
Horny goat weed
A low-growing plant of Chinese medicine (epimedium) sold mostly for sex drive and erections, and studied for bone loss after menopause. Its bone studies in people look promising but are few; its sexual-health claims have not been shown in good trials.
Traditional use
Epimedium has been used in Chinese medicine for centuries as a tonic, an aphrodisiac and for rheumatism; the Chinese name, yin yang huo, refers to goats said to mate after grazing it. Today it is sold in capsules and tablets, often mixed with other herbs, for sexual function, and it is studied in China for osteoporosis.
What studies show
- Limited
Bone loss after menopause: a 24-month trial of 100 women found that epimedium flavonoids kept bone density steady while it fell in the placebo group. A 2025 review of 10 trials in people with osteoporosis found better bone density, but asked for higher-quality studies.
- Insufficient
Sex drive and erections: LiverTox says the promising effects reported for sexual satisfaction, blood pressure and heart disease have not been proven in rigorous controlled trials; a 2015 review of men's sexual-health supplements found a dearth of evidence for it.
Be careful of
Cautions
- NoteLiverTox rates it an unlikely cause of liver injury and says it is generally well tolerated; minor side effects include stomach discomfort and nausea. Rare allergic reactions, rashes and skin inflammation have been described.
- NoteCase reports describe severe muscle spasms with signs of muscle and kidney strain in a man taking an internet-bought epimedium supplement, and a rash with a product combining it with ginkgo.
- InteractionIt is often sold in multi-ingredient products, and rare liver injury has been reported with some of these, though not clearly from epimedium. Check every ingredient on the label.
- PregnancyThe sources read here give no safety information for pregnancy or breastfeeding. Talk with your clinician first.
- Ask a clinicianTalk with a clinician or pharmacist before using this if you take prescription medicines, are pregnant or breastfeeding, or are giving it to a child.
From the old books
What herbals and dispensaries of the past printed. History, in their words.
“It is a Berberidaceous plant said to have strong aphrodisiac properties. Goats eating the plant are said to be incited to excessive copulation, hence the Chinese name.”
Sources
- Horny Goat Weed — LiverTox (opens in a new tab) · NIH · read September 25, 2026
- Epimedium-derived phytoestrogen flavonoids exert beneficial effect on preventing bone loss in late postmenopausal women: a 24-month randomized, double-blind and placebo-controlled trial (opens in a new tab) · NIH · read September 25, 2026
- The efficacy and safety of Epimedium in the treatment of primary osteoporosis: a systematic review and meta-analysis (opens in a new tab) · NIH · read September 25, 2026
- Herba Epimedium (Horny Goat Weed) Toxicity With Severe Muscle Spasms and Elevated Creatine Kinase and Creatinine: A Case Report (opens in a new tab) · NIH · read September 25, 2026
Reviewed September 25, 2026.