Horny Goat Weed Common names: Horny goat weed, barrenwort, yin yang huo
Botanical names: Epimedium grandiflorum, Epimedium sagittatum, Epimedium pubescens, Epimedium brevicornum, Epimedium koreanum
© Martin Wall
Parts used and where grown
The leaves of various species of Epimedium have been used as the herb known as yin yang huo, which literally translates as horny goat weed, in traditional Chinese medicine. The various species grow naturally from southern central to northern coastal China as well as Korea. Other species of Epimedium are found in many parts of the world, though their similarity to horny goat weed is uncertain.
Horny goat weed has been used in connection with the following conditions (refer to the individual health concern for complete information):
Historical or traditional use (may or may not be supported by scientific studies)
Horny goat weed has played a vital, multifaceted role in traditional Asian medicine for at least 1,000 years. It is considered a yang tonic, particularly for the "energetic organ" known as the kidney (which corresponds to some extent to the Western concept of the kidney). Enhancing kidney energy in this setting correlates to improving sexual function and fertility.1 Animal studies conducted in China have investigated the use of this herb within the traditional conception of a yang tonic and found effective for that purpose.2 It is also considered helpful for combating what is known as wind-damp-cold blocking circulation of the body’s dynamic life energy, or qi, which in Western terms is similar to hardening of the arteries and related complications. It is particularly used to help people recover from strokes.
In most cases, herbs in traditional Asian medicine are not used singly, but rather as a component of multiherb formulations. One animal study in China found that a combination of horny goat weed and three other herbs was effective at reducing osteoporosis resulting from the use of cortisone-like drugs, but none of the four herbs used alone was effective.3 This finding supports the traditional notion that horny goat weed may be particularly beneficial when used in combination with other herbs.
Active constituents
Horny goat weed contains a number of flavonoids, some of which show estrogen-inhibiting properties in the test tube.4 These hormonal actions may be part of the reason horny goat weed has been used traditionally to treat sexual disorders, and why it has shown efficacy in clinical trials in patients with kidney failure for improving sex drive.5 Other flavonoids in horny goat weed, such as icariin, appear to stimulate the cells that build bone (osteoblasts).6 Rats given flavonoid extracts of horny goat weed are protected against osteoporosis.7 A number of flavonoids showed effects on the immune system that are both stimulating and suppressing depending on the circumstances in the test tube.8 Preliminary human trials in people with kidney disease undergoing dialysis confirm that horny goat weed can improve the function of various portions of the immune system.9 Icariin protects liver cells in the test tube.10
A water extract of horny goat weed has been shown to inhibit growth of new blood vessels, a property potentially useful in stopping the growth of cancerous tumors.11 Extracts of the herb were moderately effective at inhibiting growth of cancer cells in the test tube, though icariin by itself was not.12 Icariin was effective at causing some cancer cells to become more normal in the test tube.13
Lignans have also been found in various species of horny goat weed. Some lignans have been shown in one animal study to stimulate nerve growth.14
A combination of horny goat weed with three other herbs has been shown to inhibit inflammation in several animal studies.15 This might in part explain the observed utility in early studies on the use of horny goat weed–containing formulas in people with hay fever.16 The immune effects of the flavonoids might also be relevant here.
A water extract of the whole herb of horny goat weed was shown to strongly inhibit a herpes simplex virus in the test tube.17 Water extracts of horny goat weed have also been shown to reduce blood pressure in several animal species and to reduce cholesterol levels.18 These extracts have been reported to be helpful in combination with several other herbs in people with what is described in Chinese medicine as kidney yang deficiency, presenting as what would be called in the West hardening of the arteries to the brain leading to dementia.19 This formula was more effective than one not containing horny goat weed. The effectiveness was correlated with antioxidant, cholesterol-lowering, and anti-inflammatory effects seen in the people taking the horny goat weed–containing formula.
How much is usually taken?
Traditionally 5 grams (1 tsp) of horny goat weed was taken three times per day, usually after being simmered (decocted) in 250 ml (1 pint) of water for 10 to 15 minutes.20 A similar amount can be taken in the form of granules, which are freeze-dried grains made from decocted herb, or powdered herb in capsules.
Are there any side effects or interactions?
In traditional Chinese medicine, horny goat weed is usually combined with yin tonic herbs when used long term for support of sexual health.21 If this is not done, it is believed the herb could cause problems such as aggressiveness, irritability, fever, or other “hot” symptoms (such as racing heart beat). In animal studies, prolonged use of excessive amounts of horny goat weed was associated with decreased thyroid activity.22
Are there any drug interactions?
Certain medicines may interact with horny goat weed. Refer to drug interactions for a list of those medicines.
References (To view, roll mouse over the "References" heading; to hide, click on the heading)
1. Bensky D, Gamble A, Kaptchuk T. Chinese Herbal Medicine Materia Medica. Revised Edition, Seattle: Eastland Press, 1992.
2. Zheng J, Luo Y, Meng X, et al. Effects of Sichuan herba Epimedii on the concentration of plasma middle molecular substances and sulfhydryl group of "yang-deficiency" model animal. Zhongguo Zhong Yao Za Zhi 1995;20:238–9, 254 [in Chinese].
3. Liu HD, Lin FS, Li E, et al. The influence of the different components of nourishing kidney herbs on osteoporosis rats. Zhongguo Zhong Yao Za Zhi 2003;28:262–5 [in Chinese].
4. Yap SP, Shen P, Butler MS, et al. New estrogenic prenylflavone from Epimedium brevicornum inhibits the growth of breast cancer cells. Planta Med 2005;71:114–9.
5. Liao HJ, Chen XM, Li WG. 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;15:202–4 [in Chinese].
6. Meng FH, Li YB, Xiong ZL, et al. Osteoblastic proliferative activity of Epimedium brevicornum Maxim. Phytomedicine 2005;12:189–93.
7. Chen KM, Ge BF, Ma HP, Zheng RL. 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;59:61–4.
8. Liang HR, Vuorela P, Vuorela H, Hiltunen R. Isolation and immunomodulatory effect of flavonol glycosides from Epimedium hunanense. Planta Med 1997;63:316–9.
9. Chen X, Zhou M, 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;34:102–4 [in Chinese].
10. Lee MK, Choi YJ, Sung SH, et al. Antihepatotoxic activity of icariin, a major constituent of Epimedium koreanum. Planta Med 1995;61:523–6.
11. Wang S, Zheng Z, Weng Y, et al. Angiogenesis and anti-angiogenesis activity of Chinese medicinal herbal extracts. Life Sci 2004;74:2467–78.
12. 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.
13. Zhao Y, Cui Z, Zhang L. Effects of icariin on the differentiation of HL-60 cells. Zhonghua Zhong Liu Za Zhi 1997;19:53–5 [in Chinese].
14. Chiba K, Yamazaki M, Umegaki E, et al. Neuritogenesis of herbal (+)- and (-)-syringaresinols separated by chiral HPLC in PC12h and Neuro2a cells. Biol Pharm Bull 2002;25:791–3.
15. Wei RB, Huo HR, Li XQ, et al. Study on antiinflammatory effect of a compound TCM agent containing ant extractive in animal models. Zhongguo Zhong Yao Za Zhi 2002;27:215–8.
16. Yu YJ. Effect of tian-huang-ling granule in the treatment of allergic rhinitis. Zhong Xi Yi Jie He Za Zhi 1989;9:720–1, 708 [in Chinese].
17. Zheng MS. An experimental study of the anti-HSV-II action of 500 herbal drugs. J Tradit Chin Med 1989;9:113–6.
18. Chen JK, Chen TT. Chinese Medical Herbology and Pharmacology. City of Industry, CA: Art of Medicine Press, Inc., 2003.
19. Tan X, 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;23:450–2 [in Chinese].
20. Chen JK, Chen TT. Chinese Medical Herbology and Pharmacology. City of Industry, CA: Art of Medicine Press, Inc., 2003.
21. Chen JK, Chen TT. Chinese Medical Herbology and Pharmacology. City of Industry, CA: Art of Medicine Press, Inc., 2003.
22. Chen MD, Kuang AK, Chen JL. Influence of yang-restoring herb medicines upon metabolism of thyroid hormone in normal rats and a drug administration schedule. Zhong Xi Yi Jie He Za Zhi 1989;9:93–5, 70 [in Chinese].
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The information presented in Healthnotes is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires September 2008.