Evidence-based·Last reviewed May 30, 2026·How we grade evidence

Epimedium

BotanicalYinyanghuo B

Useful mainly for people drawn to traditional use for sexual function, though human evidence is weak.

Quick decision guide

May help most

people drawn to traditional use for sexual function, though human evidence is weak

Common dosing range

250–1,000 mg/day standardized extract

When to expect effects

Weeks (4–12)

Watch out for

may affect blood pressure unpredictably and overlaps with PDE5 inhibitors

What is it

Epimedium is a genus of flowering plants whose leaves and aerial parts have been used in traditional Chinese medicine for centuries. Also known as horny goat weed, yin yang huo, or barrenwort, it is used for sexual function, bone health, fatigue, and as a tonic. The most-studied species is Epimedium brevicornum, and the primary bioactive compound is icariin.

Is it worth it for you?

Use this as a quick fit check, not a diagnosis.

Worth considering if…

You accept that human evidence is largely preclinical and traditional
You want a low-cost traditional botanical to trial
You are not on cardiovascular or erectile-dysfunction medications

Probably skip if…

You want a proven treatment for erectile dysfunction
You take blood pressure, blood-thinning, or PDE5 medications
You have a hormone-sensitive cancer or cardiovascular disease

Evidence at a glance

bone health and osteoporosis

Limited Evidence
Effect
Small
Best fit
postmenopausal women, in a research context only
Time
Months

erectile dysfunction

Mixed Evidence
Effect
Unclear
Best fit
men with mild erectile dysfunction open to traditional options
Time
Weeks

Evidence for 2 uses

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

bone health and osteoporosis

Biomarker support
Limited Evidence

Icariin affects osteoblast activity in laboratory models, and a few small human studies have examined bone-turnover markers and bone mineral density. Evidence is preliminary and not sufficient to support use for preventing fractures.

Effect size
Small
Time to effect
Months
Best fit
postmenopausal women, in a research context only

Bottom line: Early biomarker-level signal for bone support; not established for clinical bone outcomes.

SourceYong et al., 2021 — PubMedZhang et al., 2007 — PubMed

erectile dysfunction

Mechanism only
Mixed Evidence

Icariin shows PDE5-inhibitory activity in vitro, mechanistically similar to prescription ED drugs but far weaker. Well-controlled human trials are lacking; most evidence is preclinical or low-quality and Chinese-language. No reliable clinical effect on erectile function has been established.

Effect size
Unclear
Time to effect
Weeks
Best fit
men with mild erectile dysfunction open to traditional options
Less likely
men expecting an effect comparable to prescription PDE5 inhibitors

Bottom line: A plausible mechanism but essentially no quality human evidence for erectile dysfunction.

Evidence is mixed

Strong in vitro rationale contrasts with an absence of robust randomized human trials, so clinical benefit remains unproven.

How it works

Epimedium contains flavonoid glycosides, most notably icariin, icariside I and II, and related compounds. Icariin has been the focus of most modern research and has shown phosphodiesterase type 5 (PDE5) inhibitory activity in vitro, mechanistically similar to prescription erectile dysfunction medications, although at much lower potency than pharmaceutical PDE5 inhibitors. Other studied mechanisms include effects on nitric oxide signaling, vascular endothelial function, and possible influence on osteoblast activity (relevant to traditional use for bone support). Animal studies have explored effects on testosterone, sperm parameters, and cognitive function. Anti-inflammatory and antioxidant properties have also been documented in laboratory and animal studies. Despite considerable preclinical research and long traditional use, well-controlled human clinical trials of Epimedium for most marketed uses are limited. Most studies have been small, of variable quality, and many are published in Chinese-language journals with limited access for Western researchers.

How to take it

1. Typical dose
250–1,000 mg/day standardized extract (10–60% icariin)
2. Timing
divided 2–3 times daily; avoid late evening if stimulating
3. With food
with or without food
4. How long to try
trial 4–12 weeks before judging

What to track

sexual function
heart rate and blood pressure
sleep
any irritability or nosebleeds

4 commercial forms

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

Standardized Epimedium extract

Most common modern supplement form.

Typically standardized to icariin content (10-60%)

Pure icariin

Provides standardized icariin without other plant compounds.

Isolated active compound, more consistent dosing

Dried herb powder (yin yang huo)

Used in capsules and traditional preparations.

Whole-herb form, variable potency

Liquid extract / tincture

Used in herbalist formulas.

Alcohol-based extraction

Safety

Know the common side effects, key cautions, and who should avoid it.

Common side effects

nauseadizzinessdry mouthnosebleedirritabilityelevated heart rate

Serious risks

Who should avoid it

Pregnancy & breastfeeding

Avoid in pregnancy and breastfeeding due to insufficient safety data and traditional cautions.

SourceMemorial Sloan Kettering — Epimedium — MSKCC About Herbs

Interactions

antihypertensivesModerate

unpredictable effects on blood pressure

SourceMemorial Sloan Kettering — Epimedium — MSKCC About Herbs
PDE5 inhibitorsModerate

mechanistic overlap may compound effects

SourceMemorial Sloan Kettering — Epimedium — MSKCC About Herbs
anticoagulants and antiplateletsModerate

may affect bleeding risk

SourceMemorial Sloan Kettering — Epimedium — MSKCC About Herbs

Choosing a product

What to look for on the label — and what to be skeptical of.

Look for…

named species
stated icariin standardization percentage
third-party tested for identity and contaminants

Be skeptical of…

natural Viagra
guaranteed ED cure
testosterone booster
instant performance

Frequently asked questions

Is Epimedium the same as horny goat weed?⌄

Yes. Horny goat weed is the common name for Epimedium. The Chinese name is yin yang huo. The most-studied species for supplements is Epimedium brevicornum.

Does Epimedium work like Viagra?⌄

Its active compound icariin has PDE5 inhibitory activity in laboratory studies, the same mechanism as sildenafil (Viagra). However, icariin is much less potent than pharmaceutical PDE5 inhibitors, and clinical effects are likely smaller.

Which Epimedium species is best?⌄

E. brevicornum and E. sagittatum are the most-studied species. Standardized extracts list icariin content; higher percentages indicate more concentrated extracts.

Can Epimedium help with osteoporosis?⌄

Some Chinese clinical trials suggest modest benefit on bone markers in postmenopausal women. Western clinical evidence is limited. Epimedium is not a substitute for evaluated osteoporosis treatment.

Is Epimedium safe with blood pressure medications?⌄

Possible interactions with antihypertensives have been suggested. Discuss with your clinician if you take prescription blood pressure medications before starting Epimedium.

References by claim

bone health and osteoporosis

Yong et al., 2021 — PubMed (2021) link

Zhang et al., 2007 — PubMed (2007) link

Safety

Memorial Sloan Kettering — Epimedium — MSKCC About Herbs link

Track Epimedium with Pilora

Set up dose reminders, check interactions, and join the community in the Pilora iPhone app.

Coming to App Store
Evidence-based·Last reviewed May 30, 2026·Evidence current as of May 30, 2026·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.