Epidedium

Botanical

What is it

Epimedium (commonly misspelled 'Epidedium'), also known as horny goat weed or yin yang huo, is a genus of leafy plants used in traditional Chinese medicine. The leaves are the main medicinal part.

Evidence for 2 uses

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

Bone health/osteoporosis

Limited Evidence

Animal studies and small human trials suggest icariin may support bone density, but evidence is preliminary.

Erectile dysfunction (traditional use)

Mixed Evidence

Icariin shows PDE5 inhibitory activity in laboratory and animal studies. Human clinical evidence specifically for epimedium supplementation in ED is limited and mostly anecdotal.

How it works

Epimedium contains icariin and related flavonoids, the most studied active compounds. Icariin is a phosphodiesterase-5 (PDE5) inhibitor in vitro, similar in mechanism to sildenafil, though much weaker. It also has osteogenic effects in animal models and may influence sex hormone signaling. In traditional Chinese medicine, epimedium is used as a 'kidney yang' tonic for sexual dysfunction, fatigue, and bone weakness. Human clinical evidence is limited; most studies use animal models or combination formulas.

Dosage

There is no established RDA or UL. Standardized icariin extracts typically deliver 200-1000 mg of epimedium extract daily, often standardized to 10-20% icariin. Follow product labeling.

When and how to take it

WHEN: Often taken 30-60 minutes before intended use for sexual function applications. HOW: Take with water, with or without food.

2 commercial forms

Compare the main delivery options and what they’re best suited for.

Standardized icariin extract

Most common supplement form, often labeled as 10-20% icariin.

Concentrated extracts provide more consistent icariin content.

Whole leaf powder

Less concentrated, used in traditional preparations.

Variable icariin content depending on source and species.

Safety

Generally tolerated short-term; long-term safety data are limited. Reported side effects include dizziness, nausea, dry mouth, and (rarely) rapid heart rate and breathing problems at high doses. Case reports describe hypomania and tachyarrhythmia.

Who should be cautious

Avoid during pregnancy and breastfeeding. Use cautiously with cardiovascular disease, hormone-sensitive conditions, or if taking nitrates or PDE5 inhibitors. Discuss with a clinician before combining with prescription medications.

Interactions

Potential additive effects with PDE5 inhibitors (sildenafil, tadalafil), antihypertensives, and anticoagulants. May lower blood pressure or affect testosterone-related medications.

Frequently asked questions

Does horny goat weed work like Viagra?⌄

Icariin has PDE5 inhibitor activity in vitro, but it is much weaker than prescription PDE5 inhibitors, and human evidence for clinically meaningful effects on erectile function is limited.

Is it safe to take long-term?⌄

Long-term safety data are limited. Most studies have evaluated short to medium-term use (8-12 weeks).

References

Epidedium on NIH DSLD (US supplement label database) — NIH Dietary Supplement Label Database link

Research on Epidedium (PubMed search) — PubMed link

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Evidence-based·How we grade evidence

Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.