What is it?
People use horny goat weed for sexual performance problems, such as erectile dysfunction (ED) and low sexual desire, as well as weak and brittle bones (osteoporosis), health problems after menopause, and joint pain, but there is limited scientific research to support any of these uses.
How effective is it?
Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.
The effectiveness ratings for HORNY GOAT WEED are as follows:
Insufficient evidence to rate effectiveness for...
- Weak and brittle bones (osteoporosis). Taking a specific extract of horny goat weed for 24 months in combination with calcium supplements decreases bone loss of the spine and hip in women who have passed menopause better than taking calcium alone. Chemicals in the extract act somewhat like the hormone estrogen.
- Health problems after menopause.Taking horny goat weed water extract for 6 months can decrease cholesterol and increase estrogen levels in postmenopausal women.
- Ejaculation problems.
- Erectile dysfunction (ED).
- Heart disease.
- High blood pressure.
- Joint pain.
- Liver disease.
- Memory loss.
- Sexual problems.
- Other conditions.
How does it work?
Are there safety concerns?
However, some types of horny goat weed are POSSIBLY UNSAFE when used for a long period of time or in high doses. Long-term use of these other forms of horny goat weed might cause dizziness, vomiting, dry mouth, thirst, and nosebleed. Taking large amounts of horny goat weed might cause spasms and severe breathing problems.
A heart rhythm problem has also been reported in one man who took horny goat weed in a commercial product used for sexual enhancement. A specific multi-ingredient commercial product (Enzyte, Berkeley Premium Nutraceuticals) that contains horny goat weed might cause abnormal heart beats. These changes might increase the chance of having a heart rhythm problems. A case of liver toxicity has been reported in a man who took this same product (Enzyte, Berkeley Premium Nutraceuticals). However, since this product contains multiple ingredients, it is not clear if these effects are caused by horny goat weed or other ingredients. In the case of liver toxicity, it's possible that the side effect was an abnormal reaction that would be unlikely to occur in other patients.
Special precautions & warnings:Pregnancy and breast-feeding: Horny goat weed is POSSIBLY UNSAFE when taken by mouth during pregnancy. There is a concern that it might harm the developing fetus. Avoid using it. Not enough it known about the safety of using horny goat weed during breast-feeding. Stay on the safe side and avoid using.
Bleeding disorders: Horny goat weed might slow blood clotting. This might increase the risk of bleeding. In theory, taking horny goat weed might make bleeding disorders worse.
Hormone sensitive cancers and conditions: Horny goat weed acts like estrogen and can increase estrogen levels in some women. Horny goat weed might make estrogen-sensitive conditions, such as breast and uterine cancer, worse.
Low blood pressure: Horny goat weed might lower blood pressure. In people who already have low blood pressure, using horny goat weed might drop blood pressure too low and increase the risk of fainting.
Surgery: Horny goat weed might slow blood clotting. This might increase the risk of bleeding during surgery. Stop taking horny goat weed at least 2 weeks before surgery.
Are there interactions with medications?
- Horny goat weed might have some of the same effects as estrogen and might increase blood levels of estrogen in some women. Taking horny goat weed with estrogen might increase the effects and side effects of estrogen.
Some estrogen pills include conjugated equine estrogens (Premarin), ethinyl estradiol, estradiol, and others.
- Medications changed by the liver (Cytochrome P450 1A2 (CYP1A2) substrates)
- Some medications are changed and broken down by the liver. Horny goat weed might decrease how quickly the liver breaks down some medications. Taking horny goat weed along with some medications that are changed by the liver might increase the effects and side effects of some medications. Before taking horny goat weed, talk to your healthcare provider if you take any medications that are changed by the liver.
Some of these medications that are changed by the liver include caffeine, clozapine (Clozaril), cyclobenzaprine (Flexeril), fluvoxamine (Luvox), haloperidol (Haldol), imipramine (Tofranil), mexiletine (Mexitil), olanzapine (Zyprexa), pentazocine (Talwin), propranolol (Inderal), tacrine (Cognex), theophylline (Slo-bid, Theo-Dur, others), zileuton (Zyflo), Zolmitriptan (Zomig), and others.
- Medications changed by the liver (Cytochrome P450 2B6 (CYP2B6) substrates)
- Some medications are changed and broken down by the liver. Horny goat weed might decrease how quickly the liver breaks down some medications. Taking horny goat weed along with some medications that are broken down by the liver can increase the effects and side effects of some medications. Before taking horny goat weed, talk to your healthcare provider if you take any medications that are changed by the liver.
Some medications that are changed by the liver include bupropion (Wellbutrin), cyclophosphamide (Cytoxan), dexamethasone (Decadron), efavirenz (Sustiva), ketamine (Ketalar), methadone (Dolophine), nevirapine (Viramune), orphenadrine (Norflex), phenobarbital, sertraline (Zoloft), tamoxifen (Nolvadex), valproic acid (Depakote), and numerous others.
- Medications for high blood pressure (Antihypertensive drugs)
- Horny goat weed might lower blood pressure. Taking horny goat weed along with medications for high blood pressure might cause your blood pressure to go too low.
Some medications for high blood pressure include captopril (Capoten), enalapril (Vasotec), losartan (Cozaar), valsartan (Diovan), diltiazem (Cardizem), Amlodipine (Norvasc), hydrochlorothiazide (HydroDiuril), furosemide (Lasix), and many others.
- Medications that can cause an irregular heartbeat (QT interval-prolonging drugs)
- Horny goat weed might increase your heart rate. Taking horny goat weed along with medications that can cause an irregular heartbeat might cause serious side effects including irregular heartbeat.
Some medications that can cause an irregular heartbeat include amiodarone (Cordarone), disopyramide (Norpace), dofetilide (Tikosyn), ibutilide (Corvert), procainamide (Pronestyl), quinidine, sotalol (Betapace), thioridazine (Mellaril), and many others.
- Medications that slow blood clotting (Anticoagulant / Antiplatelet drugs)
- Horny goat weed might slow blood clotting. Taking horny goat weed along with medications that also slow clotting might increase the chances of bruising and bleeding.
Some medications that slow blood clotting include aspirin, clopidogrel (Plavix), diclofenac (Voltaren, Cataflam, others), ibuprofen (Advil, Motrin, others), naproxen (Anaprox, Naprosyn, others), dalteparin (Fragmin), enoxaparin (Lovenox), heparin, warfarin (Coumadin), and others.
Are there interactions with herbs and supplements?
- Herbs and supplements that might lower blood pressure
- Horny goat weed might lower blood pressure. Taking it along with other herbs and supplements that could decrease blood pressure might increase risk of blood pressure dropping too low. Some of these herbs and supplements include andrographis, casein peptides, cat's claw, coenzyme Q-10, fish oil, L-arginine, lycium, stinging nettle, theanine, and others.
- Herbs and supplements that might slow blood clotting
- Horny goat weed might slow blood clotting. Taking horny goat weed along with other herbs and supplements that also slow clotting might increase the chances of bruising and bleeding. These herbs include angelica, clove, danshen, garlic, ginger, ginkgo, quassia, red clover, turmeric, willow, and others.
Are there interactions with foods?
- There are no known interactions with foods.
What dose is used?
To learn more about how this article was written, please see the Natural Medicines Comprehensive Database methodology.
- Huang S, Meng N, Chang B, Quan X, Yuan R, Li B. Anti-inflammatory activity of Epimedium brevicornu maxim ethanol extract. J Med Food. 2018;21:726-733. View abstract.
- Teo YL, Cheong WF, Cazenave-Gassiot A, et al. Pharmacokinetics of prenylflavonoids following oral ingestion of standardized epimedium extract in humans. Planta Med. 2019;85:347-355. View abstract.
- Indran IR, Liang RL, Min TE, Yong EL. Preclinical studies and clinical evaluation of compounds from the genus Epimedium for osteoporosis and bone health. Pharmacol Ther 2016;162:188-205. doi: 10.1016/j.pharmthera.2016.01.015. View abstract.
- Zhong Q, Shi Z, Zhang L, et al. The potential of Epimedium koreanum Nakai for herb-drug interaction. J Pharm Pharmacol 2017;69:1398-408. doi: 10.1111/jphp.12773. View abstract.
- Ho CC, Tan HM. Rise of herbal and traditional medicine in erectile dysfunction management. Curr Urol Rep 2011;12:470-8. View abstract.
- Corazza O, Martinotti G, Santacroce R, et al. Sexual enhancement products for sale online: raising awareness of the psychoactive effects of yohimbine, maca, horny goat weed, and Ginkgo biloba. Biomed Res Int 2014;2014:841798. View abstract.
- Ramanathan VS, Mitropoulos E, Shlopov B, et al. An Enzyte'ing' case of acute hepatitis. J Clin Gastroenterol 2011;45:834-5. View abstract.
- Zhao YL, Song HR Fei JX Liang Y Zhang BH Liu QP Wang J Hu P. The effects of Chinese yam-epimedium mixture on respiratory function and quality of life in patients with chronic obstructive pulmonary disease. J Tradit Chin Med. 2012;32:203-207.
- Wu H, Lu Y Du S Chen W Wang Y. [Comparative study on absorption kinetics in intestines of rats of epimedii foliunm of Xianlinggubao capsules prepared by different processes]. [Article in Chinese]. Zhongguo Zhong Yao Za Zhi. 2011;36:2648-2652.
- Lee, M. K., Choi, Y. J., Sung, S. H., Shin, D. I., Kim, J. W., and Kim, Y. C. Antihepatotoxic activity of icariin, a major constituent of Epimedium koreanum. Planta Med 1995;61:523-526. View abstract.
- Chen, X., Zhou, M., and Wang, J. [Effect of epimedium sagittatum on soluble IL-2 receptor and IL-6 levels in patients undergoing hemodialysis]. Zhonghua Nei Ke.Za Zhi. 1995;34:102-104. View abstract.
- Liao, H. J., Chen, X. M., and Li, W. G. [Effect of Epimedium sagittatum on quality of life and cellular immunity in patients of hemodialysis maintenance]. Zhongguo Zhong.Xi.Yi.Jie.He.Za Zhi. 1995;15:202-204. View abstract.
- Iinuma, M., Tanaka, T., Sakakibara, N., Mizuno, M., Matsuda, H., Shiomoto, H., and Kubo, M. [Phagocytic activity of leaves of Epimedium species on mouse reticuloendotherial system]. Yakugaku Zasshi 1990;110:179-185. View abstract.
- Yan, F. F., Liu, Y., Liu, Y. F., and Zhao, Y. X. Herba Epimedii water extract elevates estrogen level and improves lipid metabolism in postmenopausal women. Phytother.Res. 2008;22:1224-1228. View abstract.
- Zhao, L., Lan, L. G., Min, X. L., Lu, A. H., Zhu, L. Q., He, X. H., and He, L. J. [Integrated treatment of traditional Chinese medicine and western medicine for early- and intermediate-stage diabetic nephropathy]. Nan.Fang Yi.Ke.Da.Xue.Xue.Bao. 2007;27:1052-1055. View abstract.
- Wang, T., Zhang, J. C., Chen, Y., Huang, F., Yang, M. S., and Xiao, P. G. [Comparison of antioxidative and antitumor activities of six flavonoids from Epimedium koreanum]. Zhongguo Zhong.Yao Za Zhi. 2007;32:715-718. View abstract.
- Wang, Y. K. and Huang, Z. Q. Protective effects of icariin on human umbilical vein endothelial cell injury induced by H2O2 in vitro. Pharmacol.Res 2005;52:174-182. View abstract.
- Yin, X. X., Chen, Z. Q., Dang, G. T., Ma, Q. J., and Liu, Z. J. [Effects of Epimedium pubescens icariine on proliferation and differentiation of human osteoblasts]. Zhongguo Zhong.Yao Za Zhi. 2005;30:289-291. View abstract.
- Wang, Z. Q. and Lou, Y. J. Proliferation-stimulating effects of icaritin and desmethylicaritin in MCF-7 cells. Eur.J Pharmacol. 11-19-2004;504:147-153. View abstract.
- Ma, A., Qi, S., Xu, D., Zhang, X., Daloze, P., and Chen, H. Baohuoside-1, a novel immunosuppressive molecule, inhibits lymphocyte activation in vitro and in vivo. Transplantation 9-27-2004;78:831-838. View abstract.
- Chen, K. M., Ge, B. F., Ma, H. P., and Zheng, R. L. The serum of rats administered flavonoid extract from Epimedium sagittatum but not the extract itself enhances the development of rat calvarial osteoblast-like cells in vitro. Pharmazie 2004;59:61-64. View abstract.
- Wu, H., Lien, E. J., and Lien, L. L. Chemical and pharmacological investigations of Epimedium species: a survey. Prog.Drug Res 2003;60:1-57. View abstract.
- Chiba, K., Yamazaki, M., Umegaki, E., Li, M. R., Xu, Z. W., Terada, S., Taka, M., Naoi, N., and Mohri, T. Neuritogenesis of herbal (+)- and (-)-syringaresinols separated by chiral HPLC in PC12h and Neuro2a cells. Biol.Pharm Bull 2002;25:791-793. View abstract.
- Zhao, Y., Cui, Z., and Zhang, L. [Effects of icariin on the differentiation of HL-60 cells]. Zhonghua Zhong.Liu Za Zhi. 1997;19:53-55. View abstract.
- Tan, X. and Weng, W. [Efficacy of epimedium compound pills in the treatment of the aged patients with kidney deficiency syndrome of ischemic cardio-cerebral vascular diseases]. Hunan.Yi.Ke.Da.Xue.Xue.Bao. 1998;23:450-452. View abstract.
- Zheng, M. S. An experimental study of the anti-HSV-II action of 500 herbal drugs. J Tradit.Chin Med 1989;9:113-116. View abstract.
- Wu, B. Y., Zou, J. H., and Meng, S. C. [Effect of wolfberry fruit and epimedium on DNA synthesis of the aging-youth 2BS fusion cells]. Zhongguo Zhong.Xi.Yi.Jie.He.Za Zhi. 2003;23:926-928. View abstract.
- Liang, R. N., Liu, J., and Lu, J. [Treatment of refractory polycystic ovary syndrome by bushen huoxue method combined with ultrasound-guided follicle aspiration]. Zhongguo Zhong Xi Yi Jie He Za Zhi 2008;28:314-317. View abstract.
- Phillips M, Sullivan B, Snyder B, et al. Effect of Enzyte on QT and QTc intervals. Arch Intern Med 2010;170:1402-4. View abstract.
- Meng FH, Li YB, Xiong ZL, et al. Osteoblastic proliferative activity of Epimedium brevicornum Maxim. Phytomedicine 2005;12:189-93. View abstract.
- Zhang X, Li Y, Yang X, et al. Inhibitory effect of Epimedium extract on S-adenosyl-L-homocysteine hydrolase and biomethylation. Life Sci 2005;78:180-6. View abstract.
- Yin XX, Chen ZQ, Liu ZJ, et al. Icariine stimulates proliferation and differentiation of human osteoblasts by increasing production of bone morphogenetic protein 2. Chin Med J (Engl) 2007;120:204-10. View abstract.
- Shen P, Guo BL, Gong Y, et al. Taxonomic, genetic, chemical and estrogenic characteristics of Epimedium species. Phytochemistry 2007;68:1448-58. View abstract.
- Yap SP, Shen P, Li J, et al. Molecular and pharmacodynamic properties of estrogenic extracts from the traditional Chinese medicinal herb, Epimedium. J Ethnopharmacol 2007;113:218-24. View abstract.
- Ning H, Xin ZC, Lin G, et al. Effects of icariin on phosphodiesterase-5 activity in vitro and cyclic guanosine monophosphate level in cavernous smooth muscle cells. Urology 2006;68:1350-4. View abstract.
- Zhang CZ, Wang SX, Zhang Y, et al. In vitro estrogenic activities of Chinese medicinal plants traditionally used for the management of menopausal symptoms. J Ethnopharmacol 2005;98:295-300. View abstract.
- De Naeyer A, Pocock V, Milligan S, De Keukeleire D. Estrogenic activity of a polyphenolic extract of the leaves of Epimedium brevicornum. Fitoterapia 2005;76:35-40. View abstract.
- Zhang G, Qin L, Shi Y. Epimedium-derived phytoestrogen flavonoids exert beneficial effect on preventing bone loss in late postmenopausal women: a 24-month randomized, double-blind and placebo-controlled trial. J Bone Miner Res 2007;22:1072-9. View abstract.
- Lin CC, Ng LT, Hsu FF, et al. Cytotoxic effects of Coptis chinensis and Epimedium sagittatum extracts and their major constituents (berberine, coptisine and icariin) on hepatoma and leukaemia cell growth. Clin Exp Pharmacol Physiol 2004;31:65-9. View abstract.
- Partin JF, Pushkin YR. Tachyarrhythmia and hypomania with horny goat weed. Psychosomatics 2004;45:536-7. View abstract.
- Cirigliano MD, Szapary PO. Horny goat weed for erectile dysfunction. Alt Med Alert 2001;4:19-22.
- Parisi GC, Zilli M, Miani MP, et al. High-fiber diet supplementation in patients with irritable bowel syndrome (IBS): a multicenter, randomized, open trial comparison between wheat bran diet and partially hydrolyzed guar gum (PHGG). Dig Dis Sci 2002;47:1697-704.. View abstract.
- Anon. In vitro screening of traditional medicines for anti-HIV activity: memorandum from a WHO meeting. Bull World Health Organ 1989;67:613-8. View abstract.
- McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
- Leung AY, Foster S. Encyclopedia of Common Natural Ingredients Used in Food, Drugs and Cosmetics. 2nd ed. New York, NY: John Wiley & Sons, 1996.