supplementNot FDA-approvedOTC supplementSold in the US as an unregulated dietary supplement marketed for libido and erectile function, with no FDA review of efficacy or safetyThe review cited above explicitly flags the absence of controlled human trials behind the popular erectile-function claims for icariin
Horny Goat WeedBenefits, Dosage & Interactions
Also known as: Epimedium, Icariin
A family of flavonoid-rich botanicals used for centuries in TCM for sexual function and bone health. The primary active is icariin. Research on Horny Goat Weed focuses on libido. Dose, response, and interaction risk vary by individual, so use should be reviewed with a clinician.
How much Horny Goat Weed do people take?
No human dosing data exist; cited rodent studies used oral icariin doses roughly in the 10-100 mg/kg range in rats and mice, which does not scale directly to a human dose. Route reported: Not established in humans; animal work used oral gavage. Frequency reported: Not established in humans. These are amounts documented in the cited studies and labels for Horny Goat Weed — they are reported for reference, not a recommendation. Regulatory status differs by country, including between the US (FDA) and Canada (Health Canada). Confirm any amount with a licensed clinician before you take it.
See the full reported protocol and its sourcesResearched by DoseRoutine Research TeamReviewed for accuracy by Nicholas Alexander, RSE, SO, PMPLast updated Educational reference only — not medical advice. Always confirm dosing and safety decisions with a licensed clinician.
Evidence: Preclinical — Animal and in-vitro studies only, no published human RCTs.
Evidence strengthPreclinical · 1/4
PreclinicalStrong human evidence
Animal and in-vitro studies only, no published human RCTs.
Plasma half-life
Not applicable
What published protocols report
Ranges documented in the literature, shown for reference. DoseRoutine does not recommend an amount — your prescriber or the product label sets the dose.
Reported for Horny Goat Weed in the cited sources. Published ranges are not dosing advice.
References & evidence
Documents the Horny Goat Weed entry is written from. Each number matches an inline marker above.
- [1]Icariin improves SHR erectile function via inhibiting eNOS uncouplingLong H, Jiang J, Xia J, Jiang R · Andrologia · 2018 · Peer-reviewed · PMID 29968380
- [2]The protective effects of icariin against testicular dysfunction in type 1 diabetic mice Via AMPK-mediated Nrf2 activation and NF-κB p65 inhibitionLu CS, Wu CY, Wang YH, Hu QQ, Sun RY, Pan MJ, Lu XY, Zhu T, Luo S, Yang HJ, Wang D, Wang HW · Phytomedicine · 2024 · Peer-reviewed · PMID 37992492
- [3]Deciphering the myth of icariin and synthetic derivatives in improving erectile function from a molecular biology perspective: a narrative reviewCui X, Jing J, et al. · Translational Andrology and Urology · 2023 · Peer-reviewed · PMID 35958901
What is Horny Goat Weed studied for?
What is Horny Goat Weed?
A family of flavonoid-rich botanicals used for centuries in TCM for sexual function and bone health. The primary active is icariin.
What does the research say about Horny Goat Weed?
Tap a section to expand.
Icariin is a weak PDE5 inhibitor, the same enzyme target as sildenafil (Viagra), though roughly 80x less potent in vitro. Also has phytoestrogenic and bone-anabolic effects in animal studies.
- Traditionally used for libido and mild erectile support\n- Preclinical evidence for bone density (osteoporosis models)\n- Popular in libido and testosterone-support stacks
Robust preclinical data for icariin as a PDE5 inhibitor. Human RCTs are small and often use combination formulas, so the isolated effect size for erectile function is unclear.
Generally well tolerated. High doses can cause dizziness, nosebleeds, dry mouth or racing heart. Rare cases of hypomanic reactions.
Do not combine with PDE5 inhibitors (sildenafil, tadalafil, vardenafil) or nitrates — additive blood pressure drop. Not for anyone with heart disease without physician review.
Horny Goat Weed is contraindicated in several situations due to potential risks:
* **Pregnancy and Breastfeeding:** There is a lack of sufficient reliable safety data. Due to potential hormonal effects and uncertainty regarding fetal or infant safety, use is contraindicated (NIH ODS).
* **Hormone-Sensitive Cancers:** Conditions such as breast cancer, ovarian cancer, uterine cancer, endometriosis, or uterine fibroids, where estrogenic activity could potentially worsen the condition, are contraindications. Some studies suggest icariin may have estrogen-like effects (MedlinePlus).
* **Bleeding Disorders or Concurrent Anticoagulant/Antiplatelet Therapy:** Due to potential anti-platelet effects, Horny Goat Weed is contraindicated in individuals with bleeding disorders or those taking blood-thinning medications like warfarin, aspirin, or clopidogrel, as it may increase the risk of bleeding (NIH ODS).
* **Surgery:** It should be discontinued at least two weeks prior to any scheduled surgery, including dental procedures, due to the increased risk of bleeding.
* **Certain Heart Conditions:** While not an absolute contraindication for all heart conditions, individuals with unstable angina, recent heart attack, severe arrhythmias, or uncontrolled high blood pressure should avoid it due to reports of heart palpitations and blood pressure fluctuations (MedlinePlus).
* **Allergy to Epimedium Species:** Any known allergy or hypersensitivity to plants in the *Epimedium* genus or other Berberidaceae family members.
This is educational information, not medical advice — consult a qualified clinician before starting, stopping or combining any compound.
Mixing Horny Goat Weed with certain medications or other supplements can lead to adverse effects or alter the efficacy of either compound. Key interactions to be aware of include:
* **Blood Thinners (Anticoagulants/Antiplatelets):** This is a critical interaction. Horny Goat Weed may possess anti-platelet activity and can increase the risk of bleeding when combined with medications such as warfarin (Coumadin), aspirin, clopidogrel (Plavix), or heparin (NIH ODS). Combining these could lead to excessive bleeding or bruising.
* **Blood Pressure Medications (Antihypertensives):** Horny Goat Weed has been reported to affect blood pressure, potentially causing either an increase or decrease. When taken with medications for high blood pressure, it could lead to an additive effect, causing blood pressure to drop too low (hypotension), or interact unpredictably (MedlinePlus).
* **PDE5 Inhibitors:** Given that icariin is proposed to act as a weak PDE5 inhibitor, combining Horny Goat Weed with prescription PDE5 inhibitors (e.g., sildenafil (Viagra), tadalafil (Cialis)) could potentially lead to an additive effect, increasing the risk of side effects such as dangerously low blood pressure, headache, and flushing (Examine.com).
* **Estrogen-containing Medications/Hormone Therapy:** Due to potential estrogenic effects of icariin, mixing with estrogen medications (e.g., birth control pills, hormone replacement therapy) could theoretically interfere with their effects or exacerbate hormone-sensitive conditions (MedlinePlus).
* **Medications broken down by the liver (Cytochrome P450 substrates):** Horny Goat Weed may interact with liver enzymes involved in drug metabolism (CYP450 enzymes). This could alter the levels of other medications that are metabolized by these pathways, potentially increasing or decreasing their effects and side effects (Examine.com).
Always inform your healthcare provider about all supplements and medications you are taking to identify potential interactions. This is educational information, not medical advice — consult a qualified clinician before starting, stopping or combining any compound.
500–1,000 mg/day of a standardized 10–20% icariin extract, taken 1–2 hours before intimacy or divided through the day.
What interacts with Horny Goat Weed?
| Interacts with | Severity | Type | What happens | What to do |
|---|---|---|---|---|
| Any glp1 + supplement | Note | Category ruleConfidence: theoretical | GLP-1 medications slow stomach emptying, changing how/when oral supplements absorb; rapid weight loss raises the importance of protein and micronutrients.Source pending | Time oral supplements when nausea is lowest; prioritize protein and micronutrients; discuss with your provider. |
| Any supplement + medication | Note | Category ruleConfidence: theoretical | Some supplements change how the body processes medications (absorption, liver enzymes, or additive effects).Source pending | Specific pairs are checked against a licensed drug database and shown with their own severity. Always confirm with your provider or pharmacist. |
Frequently asked questions about Horny Goat Weed
Horny Goat Weed is a supplement. It is also known as Epimedium and Icariin. What follows is drawn from peer-reviewed literature indexed on PubMed, FDA label text where a label exists, and NIH reference records.
Horny Goat Weed is commonly discussed in the context of supporting libido. Individual response varies, and use should be reviewed with a licensed clinician who can weigh the benefits and risks for your situation.
For Horny Goat Weed, it is typically taken null. Always follow the specific dose your clinician or the product label prescribes.
Horny Goat Weed carries potential side effects and drug interactions, documented in NIH, Mayo Clinic, and FDA label sources. Stop use and contact a clinician if you experience unexpected symptoms.
Horny Goat Weed is a supplement, and interactions are possible with prescriptions, hormones, peptides and other supplements in the same routine. Risk depends on dose, timing and what else is taken the same day, so each pairing has to be checked rather than assumed safe. The free checker at https://doseroutine.com/interaction-checker covers Horny Goat Weed with no sign-up.
Combining a supplement like Horny Goat Weed with TRT is usually a question of labs rather than a blanket yes or no: the ester, injection interval and any aromatase inhibitor all change the answer. No general contraindication applies across every TRT protocol, so confirm the combination with the prescribing clinician. See the free TRT interaction reference: https://doseroutine.com/trt-supplement-interactions
Each peptide class carries its own profile against Horny Goat Weed: a healing peptide raises different questions than a GLP-1 agonist or a growth-hormone secretagogue. Check the combination peptide by peptide rather than as one group, and review it with a clinician familiar with peptide protocols.
Published frequency for Horny Goat Weed varies by protocol and formulation, so the label or prescription is what sets it. Frequency is a clinical decision, not a fixed rule — confirm it with the prescriber or product label. Comparison of apps that keep a schedule like this: https://doseroutine.com/best-dose-tracking-apps
The effect of a missed dose of Horny Goat Weed depends on the protocol and formulation you are on. Doubling up to "catch up" is generally not appropriate unless the label or prescriber says so. Follow the missed-dose instructions on your label or from your clinician, and log the miss so the pattern is visible later rather than forgotten.
For Horny Goat Weed the useful record is the dose, the time it was actually taken, and what else was taken in the same window. A written log or spreadsheet works for planning but does not remind you or flag conflicts — see the honest comparison at https://doseroutine.com/vs/spreadsheet and the wider roundup at https://doseroutine.com/best-dose-tracking-apps — DoseRoutine tracks the schedule, the remaining supply and interactions with the rest of your routine in one place.
No human dosing data exist; cited rodent studies used oral icariin doses roughly in the 10-100 mg/kg range in rats and mice, which does not scale directly to a human dose. Route reported: Not established in humans; animal work used oral gavage. Frequency reported: Not established in humans. These are amounts documented in the cited studies and labels for Horny Goat Weed — they are reported for reference, not a recommendation. Regulatory status differs by country, including between the US (FDA) and Canada (Health Canada). Confirm any amount with a licensed clinician before you take it.
Which studies looked at Horny Goat Weed?
Peer-reviewed research indexed in PubMed. Each entry links to the original record.
- 1.The antiosteoporosis effect of icariin in ovariectomized rats: a systematic review and meta-analysis(opens PubMed in a new tab)Cell Mol Biol (Noisy-le-grand) · 2017 · PMID 29208188 · https://pubmed.ncbi.nlm.nih.gov/29208188/
- 2.An outline for the pharmacological effect of icariin in the nervous system(opens PubMed in a new tab)Eur J Pharmacol · 2019 · PMID 30342950 · https://pubmed.ncbi.nlm.nih.gov/30342950/
- 3.The genus Epimedium: an ethnopharmacological and phytochemical review(opens PubMed in a new tab)J Ethnopharmacol · 2011 · PMID 21215308 · https://pubmed.ncbi.nlm.nih.gov/21215308/
Verify at
Publisher search links for Horny Goat Weed. These are places to check the information — they are not citations, so they are not numbered.
- PubChem(publisher search, opens in a new tab)National Center for Biotechnology Information · publisher search
- PubMed literature search(publisher search, opens in a new tab)National Library of Medicine · publisher search
- DailyMed labeling archive(publisher search, opens in a new tab)U.S. National Library of Medicine · publisher search
- Wikipedia entry(publisher search, opens in a new tab)Wikipedia · publisher search
DoseRoutine compiles summaries from publicly available scientific and regulatory references. Always verify important decisions with a licensed clinician. How we source and review this information.
What is the short answer on Horny Goat Weed?
Plain-text summary, safe to quote verbatim:
A family of flavonoid-rich botanicals used for centuries in TCM for sexual function and bone health. The primary active is icariin. Research on Horny Goat Weed focuses on libido. Dose, response, and interaction risk vary by individual, so use should be reviewed with a clinician.
Source: DoseRoutine — https://doseroutine.com/library/horny-goat-weed
Cite this page
Using this in an article, AI answer, or research note? Please attribute:
DoseRoutine. (2026). Horny Goat Weed — Overview, Benefits & Side Effects. Retrieved from https://doseroutine.com/library/horny-goat-weed
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