SYS ONLINE
SUPPLEMENT_SCHOLAR
evidence · mechanism · dose
Supplements/Herb

Horny Goat Weed

aka Epimedium · Icariin

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

Libido & Sexual HealthTestosterone SupportBone Health

Overview

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

Natural sources
  • Epimedium spp.
Common forms
  • Standardized icariin 10–50%

Mechanism of action

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

Pathways
  • · PDE5 inhibition
  • · NO/cGMP

Effects on the body

Supports
Erectile function (mild)
Supports
Bone density (animal)

Organ system effects

Reproductive

Improves erectile function in mild ED.

Evidence-based benefits

Mild improvement in erectile function

Limited evidence

Potential side effects

Common
    Rare
    • · Tachycardia
    Serious

      Drug interactions

      PDE5 inhibitors / nitrates
      Additive hypotension.
      moderate

      Safety & non-supplemental interactions

      Educational summary — always confirm with your clinician or pharmacist before starting, stopping, or combining with prescription therapy.

      Avoid if you are
      • ·Pregnant or breastfeeding (insufficient safety data)
      • ·Children under 18 (unless directed by a clinician)
      • ·Pregnant or breastfeeding
      Avoid with these conditions
      • ·Hormone-sensitive cancers (breast, prostate, ovarian, uterine)
      • ·Hormone-sensitive cancers
      • ·Bleeding disorders
      • ·Hypotension
      Avoid / monitor with these medications
      • ·Hormonal contraceptives, HRT, tamoxifen, aromatase inhibitors
      • ·Antihypertensives
      • ·Anticoagulants and antiplatelets
      • ·CYP3A4 substrates
      Before surgery
      • ·Stop ≥2 weeks before surgery.

      Supplement interactions

      Pairs well with

      None listed.

      Avoid combining with

      No specific avoidances listed.

      Dosing & bioavailability

      Typical dose
      500–1000 mg of 10% icariin

      Where to buy

      Affiliate-style search links to reputable retailers. We don't endorse specific brands — verify third-party testing (USP, NSF, Informed Sport) before purchase.

      Herb
      Horny Goat W…
      Amazon
      Wide selection · fast shipping
      Herb
      Horny Goat W…
      iHerb
      Global delivery · curated brands
      Herb
      Horny Goat W…
      Thorne
      Practitioner-grade · NSF tested

      Scientific evidence (8)

      In vitroJ Sex Med · 2010

      Icariin (horny goat weed) and erectile function

      Shindel AW, et al.

      In vitro and animal study of icariin on PDE5.

      Key findings

      Icariin inhibits PDE5; clinical RCTs limited.

      Open study
      Systematic reviewPubMed (NLM) · 1970

      PubMed: Horny Goat Weed — Mild improvement in erectile function

      Live PubMed search

      Live results for "Horny Goat Weed Mild improvement in erectile function" across the PubMed/MEDLINE peer-reviewed index.

      Key findings

      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.

      Open study
      Systematic reviewPubMed (NLM) · 1970

      PubMed: Horny Goat Weed — randomized controlled trial

      Live PubMed search

      Live results for "Horny Goat Weed randomized controlled trial" across the PubMed/MEDLINE peer-reviewed index.

      Key findings

      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.

      Open study
      Systematic reviewPubMed (NLM) · 1970

      PubMed: Horny Goat Weed — meta-analysis

      Live PubMed search

      Live results for "Horny Goat Weed meta-analysis" across the PubMed/MEDLINE peer-reviewed index.

      Key findings

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

      Open study
      Systematic reviewPubMed (NLM) · 1970

      PubMed: Horny Goat Weed — pharmacokinetics

      Live PubMed search

      Live results for "Horny Goat Weed pharmacokinetics" across the PubMed/MEDLINE peer-reviewed index.

      Key findings

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

      Open study
      Systematic reviewPubMed (NLM) · 1970

      PubMed: Horny Goat Weed — safety adverse events

      Live PubMed search

      Live results for "Horny Goat Weed safety adverse events" across the PubMed/MEDLINE peer-reviewed index.

      Key findings

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

      Open study
      Systematic reviewPubMed (NLM) · 1970

      PubMed: Horny Goat Weed — dose response

      Live PubMed search

      Live results for "Horny Goat Weed dose response" across the PubMed/MEDLINE peer-reviewed index.

      Key findings

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

      Open study
      Systematic reviewGoogle Scholar · 1970

      Google Scholar: Horny Goat Weed — clinical evidence

      Live Scholar search

      Cross-database citation index for Horny Goat Weed as it relates to "clinical evidence".

      Key findings

      Includes preprints, theses, and journal articles. Useful for tracking citation counts and follow-on work.

      Open study
      Educational use only. This profile is not medical advice. Consult a qualified healthcare professional before starting any supplement, especially if you take prescription medication or have a chronic condition.