02
What Is It?
An herbal extract from the Epimedium plant, widely used in traditional Chinese medicine and in male-enhancement blends.
Product Profile & Review
SUPPLEMENT
Horny Goat Weed
A traditional herb whose compound icariin weakly inhibits PDE5 in lab studies; human evidence is lacking.
Also known as: Epimedium, Icariin, Yin yang huo
- Written by
- SynMale Editorial
- Originally Published
- October 2026
- Last Updated
- October 2026
- Medical Review
- Not yet independently reviewed
Executive Summary
- What is it?
- Herbal dietary supplement (Supplement).
- What does it contain or claim to contain?
- Icariin (claimed)
- How well verified is this specific product?
- Label Claims Only
- Most important thing to know
- Lab-based rationale, but no solid human evidence for ED; product content varies.
D
Ingredient
Epimedium extract (icariin)
Product Type
Herbal dietary supplement
Regulatory Status
Dietary Supplement
Verification
Label Claims Only
03
Claimed Active Ingredients
- CLAIMED INGREDIENTIcariinOften unstated or unstandardised
A claimed ingredient is what a label or seller states. It is not treated as confirmed.
04
What Can We Verify?
Established
- Icariin shows weak PDE5 inhibition in laboratory and animal studies.
Uncertain or unverified
- No robust human clinical trials for ED.
- Icariin content varies widely between products.
- Many blends have been found to contain hidden drugs.
05
How It Works
Icariin is proposed to inhibit PDE5, similar to prescription drugs but far more weakly. Laboratory effects have not been shown to translate into reliable effects in humans.
06
Evidence Level
DWeak / Mostly Marketing Claims
Grades run from A (strong clinical evidence) to F (unsupported or contradicted). How we grade.
07
Clinical Profile
- Drug Class
- Herbal extract
- Typical Onset
- Cannot be reliably established
- Effective Window
- Cannot be reliably established
- Typical Medical Dosing
- No established dose
08
Benefits / Potential Advantages
- Plausible mechanism from lab data
09
Limitations
- No reliable human efficacy data
- Unstandardised content
- Adulteration risk in blends
10
Side Effects & Precautions
Common effects
Dizziness, dry mouth, rapid heartbeat reported at high doses.
Major interactions & warnings
- • May interact with blood-pressure or blood-thinning medications.
- • Blends may hide prescription drugs.
11
Regulatory Status
FDA ApprovedFDA Cleared DeviceNot FDA ApprovedDietary SupplementCompounded MedicationForeign-Market MedicationUnknownUnverified
Sold as a dietary supplement; not FDA-approved for any condition.
12
Marketing Claims vs. Evidence
Claim
What the Evidence Shows
“Works like Viagra”
Lab potency is a tiny fraction of sildenafil's; no human trials confirm a comparable effect.
13
Counterfeit / Adulteration Risk
Documented
- FDA has repeatedly reported products in this category containing undeclared sildenafil, tadalafil, or chemically similar analogues.
- Undeclared amounts have, in tested samples, exceeded typical prescription doses.
Unconfirmed / speculative
- A product's unexpectedly strong effect may suggest undeclared ingredients—this cannot be confirmed without testing.
Risk & Verification Summary
Evidence Grade
D — Weak / Mostly Marketing Claims
Verification Level
Label Claims Only
Regulatory Status
Dietary Supplement
Risk Level
Moderate
No numerical performance score is shown because reliable performance data does not exist for this product.
SynMale Verdict
QUESTIONABLE
The marketing far outruns the evidence, and blended products carry adulteration risk.
Bottom Line
What You Should Know
Horny goat weed has a lab-based rationale but no solid human evidence for ED. Products vary greatly in content. Blends are a known source of hidden drugs.