icariin

PhytochemicalFlavonoid glycoside

What is it

Icariin is a prenylated flavonoid found in Epimedium species (horny goat weed). It is the main standardization marker for Epimedium extracts marketed for sexual health, bone, and energy support.

Evidence for 2 uses

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

Sexual function (erectile support)

Limited Evidence

Mechanistic PDE5 inhibition is well-described in vitro, but clinical evidence in humans for icariin or Epimedium extracts is limited and inconsistent.

Bone health (postmenopausal)

Limited Evidence

Some clinical trials of icariin and Epimedium in postmenopausal women report improvements in bone turnover markers and density. Trials are small.

How it works

Icariin is a phosphodiesterase-5 (PDE5) inhibitor in vitro at micromolar concentrations, the same enzyme target as sildenafil, though with much lower potency. It also shows estrogen-like and bone-protective effects in cell and animal studies. Reaching active PDE5-inhibitory blood levels with typical supplement doses is uncertain, and clinical evidence in humans for sexual function is preliminary.

Dosage

Epimedium extracts are typically standardized to 5-50% icariin; doses vary widely. No formal RDA.

When and how to take it

Often taken as needed for sexual health applications, or once daily for general use. Effects vary by product.

1 commercial form

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

Epimedium extract standardized to icariin

Common form.

Icariin has limited oral bioavailability; some products use icariin derivatives.

Safety

Reported side effects include rapid heartbeat, dizziness, and dry mouth. Cases of arrhythmia and one report of severe hypomania have been published with high-dose products.

Who should be cautious

Avoid with prescription PDE5 inhibitors, nitrates, or in cardiovascular disease without medical supervision. Pregnancy and breastfeeding: avoid. People with hormone-sensitive conditions should be cautious because of estrogenic activity.

Interactions

May add to effects of PDE5 inhibitors (sildenafil, tadalafil) and could risk hypotension when combined with nitrates. Potential additive effects with stimulants and antihypertensives.

Food sources

Epimedium (horny goat weed) plant

Amount
n/a
%DV
—

Frequently asked questions

Is icariin like Viagra?⌄

It targets the same enzyme (PDE5) but at much lower potency. Clinical evidence for icariin as an erectile-function aid is limited.

Can I combine icariin with PDE5 inhibitor drugs?⌄

Not without medical supervision. Combined effects on blood pressure and cardiac function could be unsafe.

References

icariin on Wikidata — Wikidata link

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

Research on icariin (PubMed search) — PubMed link

Track icariin with Pilora

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

Coming to App Store
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.