Supplement Scholar
Compound

Icariin (Horny Goat Weed)

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Icariin (Horny Goat Weed). Active flavonoid from Epimedium acting as PDE5 inhibitor.

How it works. Selective PDE5 inhibition increases cGMP in cavernosal tissue; mild estrogenic activity on bone.

What the research supports. 1 graded claims. Strongest: Improves erectile function in animal models (moderate).

How much to take. Typical dose: 60–120 mg icariin.

Side effects and interactions. 1 medication interaction listed. No serious side effects listed at normal doses.

Stacking. Pairs well with A high-quality multivitamin, Omega-3 (EPA/DHA).

Common forms. Available as Capsule or softgel, Powder, Sublingual or buccal, Liposomal liquid.

Key studies. 8 studies cited. The strongest are listed with links to PubMed.

Community. Experiences from people who have tried Icariin (Horny Goat Weed). Anecdotes are not medical advice.

Icariin (Horny Goat Weed). Active flavonoid from Epimedium acting as PDE5 inhibitor.

Molecular structureC33H40O15 · 676.7 g/mol

What it is

Active flavonoid from Epimedium acting as PDE5 inhibitor.

Food sources

Endogenously produced or biosynthesized moleculeStandardized pharmaceutical- or food-grade supplementCombined with cofactors that improve absorption or activity

Goals

Erectile FunctionLibido & Sexual HealthTestosterone SupportBone Health

How it works

Selective PDE5 inhibition increases cGMP in cavernosal tissue; mild estrogenic activity on bone.

Pathways

  • Selective PDE5 inhibition increases cGMP in cavernosal tissue
  • mild estrogenic activity on bone

Effects

  • +erectile function in animal models supports

What the research supports

Improves erectile function in animal modelsmoderate

Strong: consistent results across large trials or meta-analyses. Moderate: several trials, mostly positive. Limited: small or mixed studies. Preclinical: animal or cell research only.

Typical dose
60–120 mg icariin
TimingConsistent daily timing recommended; split larger doses if GI tolerance is a concern.
With foodEither
Best formMost evidence is based on the capsule or softgel form.
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Side effects & interactions

Common side effects

  • GI upset

Medication interactions

PDE5 inhibitorsmoderate

Additive hypotension.

Check any supplement–medication combination with your pharmacist before starting.

Combines with

Pairs well

  • A high-quality multivitaminCovers micronutrient cofactors that support most supplement pathways.
  • Omega-3 (EPA/DHA)Foundational anti-inflammatory support that complements most regimens.

Common forms

  • Capsule or softgel
  • Powder
  • Sublingual or buccal
  • Liposomal liquid

Key studies

8 studies cited in total.

PubMed: Icariin (Horny Goat Weed) — Improves erectile function in animal models ↗
Systematic review · PubMed (NLM) · 2026

Opens current human and preclinical literature matching Icariin (Horny Goat Weed) and "Improves erectile function in animal models". Filter by RCT, meta-analysis, or year on the results page.

PubMed: Icariin (Horny Goat Weed) — randomized controlled trial ↗
Systematic review · PubMed (NLM) · 2026

Opens current human and preclinical literature matching Icariin (Horny Goat Weed) and "randomized controlled trial". Filter by RCT, meta-analysis, or year on the results page.

PubMed: Icariin (Horny Goat Weed) — meta-analysis ↗
Systematic review · PubMed (NLM) · 2026

Opens current human and preclinical literature matching Icariin (Horny Goat Weed) and "meta-analysis". Filter by RCT, meta-analysis, or year on the results page.

Discussion

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