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Horny Goat Weed

Scientific Name(s): Epimedium grandiflorum L.
Common Name(s): Arrow-leaf barrenwort, Chien-Hsieh, Horny goat weed, Yin-Yang-Hua

Clinical Overview

Use

Historically, horny goat weed has been used in traditional Chinese medicine to "nourish" the kidney and as an aphrodisiac. However, clinical trial data are lacking to support these claims.

Dosing

There are no clinical studies of horny goat weed to provide a basis for dosage recommendations.

Contraindications

Contraindicated in patients with known hypersensitivity reactions to the Epimedium species.

Pregnancy/Lactation

Information regarding safety and efficacy in pregnancy and lactation is lacking. Avoid use.

Interactions

None well documented.

Adverse Reactions

High doses may cause a stimulatory effect and sweating. Arrhythmia and vasculitis have been reported.

Toxicology

Information is limited.

Botany

Horny goat weed is a rhizomatous perennial herb. It is native to Japan, Korea, and parts of China and grows on hillsides, in cliff crevices, and in shady areas. The stems contain between 1 to 3 basal leaves. The plant has light yellow, violet, red, and white flowers, which appear in spring, along with oval fruits.1, 2

History

Historically, horny goat weed was thought to possess aphrodisiac effects and was used to treat impotence, spermatorrhea, and premature ejaculation. Herba Epimedii has been used traditionally in Korea, Japan, and China for more than 2,000 years to "nourish" the kidney. However, clinical trial data are lacking to support these claims.2

Chemistry

A phytochemical review of the genus Epimedium has been published.2 The medicinal properties of the plant are primarily contained within the leaves and roots, which contain flavonol glycosides and ikarisosides. The aerial parts of the plant contain more than 30 nonflavonoidal glycosides, including ionones, sesquiterepenes, and lignins. The glycosides of the dihydrophenanthrene and bibenzyl derivatives are found only in the genus Epimedium. In vitro studies have focused on the role of the constituent icariin in erectile dysfunction.2, 3, 4, 5, 6, 7

Uses and Pharmacology

Cardiovascular

Animal data

The results of a chemical study of the flavonoid icariin, isolated from the aerial parts of E. grandiflorum, referred to a hypotensive pharmacologic effect.8

Clinical data

Although clinical trials are lacking, Herba epimedii, a traditional Chinese medicine, was reported to exert a hypotensive effect in coronary heart disease.2 Controlled clinical trials are lacking.

Erectile dysfunction

Animal data

Studies in rats have shown enhanced erectile tissue function and neurotrophic effects in vitro.9, 10 The effects have been attributed in part to the effect of the flavonol glycoside icariin in promoting release of nitric oxide in erectile tissue.11, 12, 13 A combination preparation and its individual herbal components were tested for efficacy and safety in rats. Epimedium extract increased the penile erection index compared with control, but less than the combination preparation.11 In vitro experiments have been conducted on extracts from a related plant, Epimedium brevicornum, while other studies suggest Epimedium species may exert estrogenic effects due to phytoestrogen constituents.2

Clinical data

Controlled clinical trials are lacking.

Other uses

Antiviral

In vitro inhibitory action of E. grandiflorum has been demonstrated against the HIV virus.14 E. grandiflorum has been used in combination with vitamin C in treating viral myocarditis.15

Dosing

There are no clinical studies of horny goat weed to provide a basis for dosage recommendations. Tablets and capsules are sold in varying strengths (250 to 500 mg standardized to icariin content).2

Pregnancy / Lactation

Information regarding safety and efficacy in pregnancy and lactation is lacking. Avoid use. Epimedium species may exert estrogenic effects due to phytoestrogen constituents.2

Interactions

Information is lacking.

Adverse Reactions

Clinical trials are lacking to provide information regarding adverse reactions with the use of this product. High doses may cause a stimulatory effect and sweating.2 A case report exists of tachyarrhythmia and hypomania with agitation following 2-week consumption of horny goat weed in an elderly patient with significant cardiac history. 16 Painful, maculopapular, erythematous rash occurred in an elderly patient 4 days after beginning self-prescribed treatment with supplements of Ginkgo biloba and horny goat weed. The rash was located on the legs and arms and was vasculitic in appearance.17

Toxicology

Limited information exists. Studies on Herba Epimedii did not find mutagenicity or any important toxicity, although long-term administration has been associated with a decrease in thyroid activity in animal studies.2

References

1. Lovejoy A. Epimediums. Horticulture. 1994;72:42-47.
2. Ma H, He X, Yang Y, Li M, Hao D, Jia ZJ. The genus Epimedium: an ethnopharmacological and phytochemical review. J Ethnopharmacol. 2011;134(3):519-541.
3. Fukai T, Nomura T. Seven prenylated flavonol glycosides from two Epimedium species. Phytochemistry. 1988;27(1):259-266.
4. Miyase T, Ueno A. Ionone and bibenzyl glycosides from Epimedium grandiflorum var. Thunbergianum. Phytochemistry. 1991;30(5):1727-1728.
5. Tokuoka Y, Daigo K, Takemoto T. Studies on the constituents of Epimedium. ΙΙΙ. Lignoids of Epimedium grandiflorum Morr. (author's transl) [in Japanese]. Yakugaku Zasshi. 1975;95(5):557-563.1171200
6. Tokuoka Y, Daigo K, Takemoto T. Studies on the constituents of Epimedium. V. Flavonoids of Epimedium grandiflorum Morr. (4) (author's transl) [in Japanese]. Yakugaku Zasshi. 1975;95(7):825-829.1237585
7. Yoshitama K. Anthocyanins and their distribution in the genus Epimedium. Bot Mag. 1984;97:429-435.
8. Zhu SC. Clinical observations on 36 cases of viral myocarditis treated with Epimedium grandiflorum Moor and vitamin C [in Chinese]. Zhong Xi Yi Jie He Za Zhi. 1984;4(9):523-524, 514.6240341
9. Albersen M, Shindel AW, Mwamukonda KB, Lue TF. The future is today: emerging drugs for the treatment of erectile dysfunction. Expert Opin Emerg Drugs. 2010;15(3):467-480.20415601
10. Shindel AW, Xin ZC, Lin G, et al. Erectogenic and neurotrophic effects of icariin, a purified extract of horny goat weed (Epimedium spp.) in vitro and in vivo. J Sex Med. 2010;7(4 pt 1):1518-1528.20141584
11. Qinna N, Taha H, Matalka KZ, Badwan AA. A new herbal combination, Etana, for enhancing erectile function: an efficacy and safety study in animals. Int J Impot Res. 2009;21(5):315-320.19494825
12. Liu WJ, Xin ZC, Xin H, Yuan YM, Tian L, Guo YL. Effects of icariin on erectile function and expression of nitric oxide synthase isoforms in castrated rats. Asian J Androl. 2005;7(4):381-388.16281085
13. Cirigliano MD, Szapary P. Horny goat weed for erectile dysfunction. Altern Med Alert. 2001;4:19-22.
14. In vitro screening of traditional medicines for anti-HIV activity: memorandum from a WHO meeting. Bull World Health Organ. 1989;67(6):613-618.
15. Kon L, Li Y, He A, Min A. Studies on HMQC and HMBC spectra of a hypotensive compound icariin. Chin J Magn Reson. 1996;13:595-600.
16. Partin JF, Pushkin YR. Tachyarrhythmia and hypomania with horny goat weed. Psychosomatics. 2004;45(6):536-537.15546831
17. Metz D, Weston P, Barker D. Case report of vasculitic rash induced by Ginkgo biloba and/or Horny Goat Weed. BMJ Case Rep. 2009;2009. pii: bcr07.2008.0399. Epub 2009 Mar 17.2168682710.1136/bcr.07.2008.0399

Disclaimer

This information relates to an herbal, vitamin, mineral or other dietary supplement. This product has not been reviewed by the FDA to determine whether it is safe or effective and is not subject to the quality standards and safety information collection standards that are applicable to most prescription drugs. This information should not be used to decide whether or not to take this product. This information does not endorse this product as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this product. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this product. This information is not specific medical advice and does not replace information you receive from your health care provider. You should talk with your health care provider for complete information about the risks and benefits of using this product.

This product may adversely interact with certain health and medical conditions, other prescription and over-the-counter drugs, foods, or other dietary supplements. This product may be unsafe when used before surgery or other medical procedures. It is important to fully inform your doctor about the herbal, vitamins, mineral or any other supplements you are taking before any kind of surgery or medical procedure. With the exception of certain products that are generally recognized as safe in normal quantities, including use of folic acid and prenatal vitamins during pregnancy, this product has not been sufficiently studied to determine whether it is safe to use during pregnancy or nursing or by persons younger than 2 years of age.

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