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Horny Goat Weed

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Horny Goat Weed. PDE5-inhibiting flavonoid (icariin) used for libido and erectile support.

How it works. Icariin inhibits PDE5 (weaker than sildenafil) and may mimic estrogen at low affinity.

What the research supports. 1 graded claims. Strongest: Mild improvement in erectile function (limited).

How much to take. Typical dose: 500–1000 mg of 10% 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 Standardized icariin 10–50%.

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

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

Horny Goat Weed. PDE5-inhibiting flavonoid (icariin) used for libido and erectile support.

Key compound: icariinC33H40O15 · 676.7 g/mol

What it is

PDE5-inhibiting flavonoid (icariin) used for libido and erectile support.

Also called

EpimediumIcariin

Food sources

Epimedium spp.

Goals

Libido & Sexual HealthTestosterone SupportBone Health

How it works

Icariin inhibits PDE5 (weaker than sildenafil) and may mimic estrogen at low affinity.

Pathways

  • PDE5 inhibition
  • NO/cGMP

Effects

  • +Erectile function (mild) supports
  • +Bone density (animal) supports

What the research supports

Mild improvement in erectile functionlimited

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
500–1000 mg of 10% icariin
TimingConsistent daily timing recommended; split larger doses if GI tolerance is a concern.
With foodEither with or without food.
Best formMost evidence is based on the standardized icariin 10–50% form.
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Side effects & interactions

Medication interactions

PDE5 inhibitors / nitratesmoderate

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

  • Standardized icariin 10–50%

Key studies

8 studies cited in total.

PubMed: Horny Goat Weed — Mild improvement in erectile function ↗
Systematic review · PubMed (NLM) · 2026

Opens current human and preclinical literature matching Horny Goat Weed and "Mild improvement in erectile function". Filter by RCT, meta-analysis, or year on the results page.

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

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

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

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

Discussion

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