Horny Goat Weed

Last Updated: October 6, 2023

Horny goat weed, scientifically known as Epimedium, is a plant used in traditional Chinese medicine. It is claimed to be a natural aphrodisiac. The flavonoids and other active compounds in horny goat weed may also be beneficial for cardiovascular health and brain health.

Horny Goat Weed is most often used for

What is horny goat weed?

Horny goat weed is the common name for the plant known as Epimedium, which is used in traditional Chinese herbal medicine as a tonic, an aphrodisiac, and an antirheumatic agent. It also goes by the names Herba epimdii, yin yang huo, fairy wings, and rowdy lamb herb. While over 200 compounds have been identified in horny goat weed, the main bioactive constituents appear to be flavonoids, of which icariin is the most well-studied.[2] Icariin is also the main active ingredient in horny goat weed supplements.

Horny goat weed appears to have anti-atherogenic, anti-inflammatory, antiviral, and immune-modulating effects, though most of these mechanisms have only been investigated in research animals and in vitro.

What are horny goat weed’s main benefits?

Although horny goat weed is one of the most common ingredients in male testosterone-boosting and erectile dysfunction (ED) supplements,[3] there is a lack of human evidence to support its effectiveness for these outcomes. Horny goat weed (icariin) does have pro-erectile properties in rodent models of ED.[4][5][6] One study found that horny goat weed elevated estrogen and reduced cholesterol and triglyceride levels in postmenopausal women.[7]

Some studies showed that horny goat weed appears to improve bone mineral density (BMD) and pain intensity in people with osteoporosis, both in combination with standard use medications and as an alternative treatment.[8]

In vitro and in vivo studies have suggested that horny goat weed is useful for treating cardiovascular diseases, including atherosclerosis and coronary heart disease.[9] Furthermore, recent evidence supports the neuroprotective properties of horny goat weed,[10] though human studies are needed to confirm these effects.

What are horny goat weed’s main drawbacks?

Horny goat weed appears to be safe and well-tolerated when taken orally, and only minor side effects, including abdominal discomfort and nausea, have been observed. In some cases, abnormal heart rhythms[11] and skin rashes[12] have been reported, but in both instances, horny goat weed was coingested with other herbal supplements or pharmaceuticals.

Since horny goat weed may have antihypertensive and anticoagulation effects in the body, taking it alongside medications that reduce blood pressure or prevent blood clotting (e.g., platelet inhibitors or anticoagulants) may cause unwanted side effects. Horny goat weed may also increase estrogen in women.[7]

In vitro, icariin and some of its metabolites have demonstrated inhibitory effects on specific isoforms of UDP-glucuronosyltransferase (UGT) in the gastrointestinal tract. These enzymes play a crucial role in the metabolism of orally administered drugs like opioids, naproxen, acetaminophen, and amitriptyline by facilitating their first-pass metabolic clearance. In vivo studies are required to assess the inhibitory effect of icariin’s metabolites on UGT enzymes in human participants, and to understand the potential herb-drug interactions that may occur when icariin is taken alongside medications.[13]

How does horny goat weed work?

Horny goat weed might benefit ED through its inhibition of phosphodiesterase-5 (PDE-5). This is the same mechanism exerted by pharmaceuticals like Viagra.[14] PDE-5 inhibition increases levels of cyclic GMP, which enhances smooth muscle relaxation and blood flow to the penis and promotes erection. Horny goat weed may also increase the activity of nitric oxide synthase enzymes and elevate the production of nitric oxide, which also promotes smooth muscle relaxation.[15][16]

The potential cardioprotective qualities of horny goat weed may be related to a decrease in vascular smooth muscle cell proliferation, reduced platelet activation, lipid modulation, and improvements in endothelial function.[9] The suspected neuroprotective mechanisms of horny goat weed could include the upregulation of antioxidant activity[17] and the inhibition of inflammation and oxidative stress in the brain.[18][19]

What else is Horny Goat Weed known as?
Note that Horny Goat Weed is also known as:
  • Yinyanghuo
  • Fairy Wings
  • Rowdy Lamb Herb
  • Epimedium
  • Herba Epimedii
  • Barrenwort
  • Bishop's Hat
Horny Goat Weed should not be confused with:
  • Icariin (active ingredient)
Dosage information

Testosterone boosting effects in rats have been noted at a dosage of 200mg/kg of a 40% extract (80mg/kg Icariin), and based on body weight conversions from rats to humans[1] this results in an estimated human dose of:

  • 900mg Icariin for a 150lb person
  • 1,200mg Icariin for a 200lb person
  • 1,500mg Icariin for a 250lb person

Studies that use a lower dosage of Icariin (1-10mg/kg) are approximately equal to:

  • 11-110mg Icariin for a 150lb person
  • 15-150mg Icariin for a 200lb person
  • 18-180mg Icariin for a 250lb person

The human study on postmenopausal women and bone health noted that 60mg Icariin daily was active, and might serve as the lowest active dose currently known. It also appears to fall within the above range of lower active dosages which show benefits in rats.

Examine Database: Horny Goat Weed
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Update History
2023-10-06 00:30:03

New meta-analyses added

minor

We added a few meta-analyses to our database and update the clinical effects accordingly.

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The information in this section is slated for renovation — it will soon be transformed into a more usable (and readable!) form in the coming months. As such, the text in this section may be out of date and not up to Examine’s current standards for writing style.

References
  1. ^Guidance for Industry: Estimating the Maximum safe starting dose in Initial Clinical Trials for Therapeutics in Adult Healthy Volunteers
  2. ^Horny Goat WeedLiverTox: Clinical and Research Information on Drug-Induced Liver Injury.(2012-08)
  3. ^Manish Kuchakulla, Manish Narasimman, Yash Soni, Joon Yau Leong, Premal Patel, Ranjith RamasamyA systematic review and evidence-based analysis of ingredients in popular male testosterone and erectile dysfunction supplementsInt J Impot Res.(2021 Apr)
  4. ^Shindel AW, Xin ZC, Lin G, Fandel TM, Huang YC, Banie L, Breyer BN, Garcia MM, Lin CS, Lue TFErectogenic and neurotrophic effects of icariin, a purified extract of horny goat weed (Epimedium spp.) in vitro and in vivo.J Sex Med.(2010-Apr)
  5. ^Liu WJ, Xin ZC, Xin H, Yuan YM, Tian L, Guo YLEffects of icariin on erectile function and expression of nitric oxide synthase isoforms in castrated rats.Asian J Androl.(2005-Dec)
  6. ^Tian L, Xin ZC, Liu WJ, Yang YM, Liu G, Chen L, Fu J, Wang LLEffects of icariin on the erectile function and expression of nitrogen oxide synthase isoforms in corpus cavernosum of arterigenic erectile dysfunction rat model.Zhonghua Yi Xue Za Zhi.(2004-Jun-02)
  7. ^Yan FF, Liu Y, Liu YF, Zhao YXHerba Epimedii water extract elevates estrogen level and improves lipid metabolism in postmenopausal women.Phytother Res.(2008-Sep)
  8. ^Shi S, Wang F, Huang Y, Chen B, Pei C, Huang D, Wang X, Wang Y, Kou S, Li W, Ma T, Wu Y, Wang ZEpimedium for Osteoporosis Based on Western and Eastern Medicine: An Updated Systematic Review and Meta-Analysis.Front Pharmacol.(2022)
  9. ^Fang J, Zhang YIcariin, an Anti-atherosclerotic Drug from Chinese Medicinal Herb Horny Goat Weed.Front Pharmacol.(2017)
  10. ^Wang S, Ma J, Zeng Y, Zhou G, Wang Y, Zhou W, Sun X, Wu MIcariin, an Up-and-Coming Bioactive Compound Against Neurological Diseases: Network Pharmacology-Based Study and Literature Review.Drug Des Devel Ther.(2021)
  11. ^Partin JF, Pushkin YRTachyarrhythmia and hypomania with horny goat weed.Psychosomatics.(2004)
  12. ^Metz D, Weston P, Barker DCase report of vasculitic rash induced by Ginkgo biloba and/or Horny Goat Weed.BMJ Case Rep.(2009)
  13. ^Cao YF, He RR, Cao J, Chen JX, Huang T, Liu YDrug-Drug Interactions Potential of Icariin and Its Intestinal Metabolites via Inhibition of Intestinal UDP-Glucuronosyltransferases.Evid Based Complement Alternat Med.(2012)
  14. ^Ning H, Xin ZC, Lin G, Banie L, Lue TF, Lin CSEffects of icariin on phosphodiesterase-5 activity in vitro and cyclic guanosine monophosphate level in cavernous smooth muscle cells.Urology.(2006-Dec)
  15. ^Chung BH, Kim JD, Kim CK, Kim JH, Won MH, Lee HS, Dong MS, Ha KS, Kwon YG, Kim YMIcariin stimulates angiogenesis by activating the MEK/ERK- and PI3K/Akt/eNOS-dependent signal pathways in human endothelial cells.Biochem Biophys Res Commun.(2008-Nov-14)
  16. ^Xu HB, Huang ZQIcariin enhances endothelial nitric-oxide synthase expression on human endothelial cells in vitro.Vascul Pharmacol.(2007-Jul)
  17. ^He XL, Zhou WQ, Bi MG, Du GHNeuroprotective effects of icariin on memory impairment and neurochemical deficits in senescence-accelerated mouse prone 8 (SAMP8) mice.Brain Res.(2010-Jun-02)
  18. ^Li WW, Gao XM, Wang XM, Guo H, Zhang BLIcariin inhibits hydrogen peroxide-induced toxicity through inhibition of phosphorylation of JNK/p38 MAPK and p53 activity.Mutat Res.(2011-Mar-15)
  19. ^Liu B, Zhang H, Xu C, Yang G, Tao J, Huang J, Wu J, Duan X, Cao Y, Dong JNeuroprotective effects of icariin on corticosterone-induced apoptosis in primary cultured rat hippocampal neurons.Brain Res.(2011-Feb-23)
Examine Database References