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Presented by: UT El Paso / Austin Cooperative Pharmacy Program & Paso del Norte Health Foundation

Horny Goat Weed


Compilation by Armando Gonzalez Stuart, PhD.

Scientific Name:

Epimedium sagittatum

Botanical Family:

Berberidaceae

Other Common Name:

Epimedium,Yinyanghuo, Sagittate epimedium (Quattrocchi, 2012)

Where is it found?

China, the Himalayas, and Japan (Mabberley, 2008; Quattrocchi, 2012).

Parts of the plant used:

The leaves, stems, and flowers.

How is it used?

Horny goat weed is available as an herbal supplement, usually in raw herb, tablet, or capsule form, and is sometimes combined with other herbs such as Yohimbé bark ( Pausinystalia johimbe), Saw palmetto (Serenoa repens), and Maca (Lepidium meyenii), for example.

What is it used for?

Various species of the botanical genus Epimedium are purported to have aphrodisiac properties, especially E. sagittatum. For this reason, the plants are employed to treat impotence, as well as to increase libido or sexual desire. This plant is also used to treat arthritis and tracheitis, as well as chronic pain in the lower body.

Various species of Epimedium are also used in Traditional Chinese Medicine (TCM) to treat rheumatism and hypertension (high blood pressure) in menopausal women (Zhang, 1996; Tang and Eisenbrand, 2011; Quattrocchi, 2012).

Horny goat weed’s main active ingredient is a known as icariin, which can be found in certain herbal products as a standardized extract which range from 5% - 60% potency. Icariin is purported to work by increasing levels of certain chemicals in the body, such as nitric oxide, which relaxes smooth muscle (Tang and Eisenbrand, 2011). Laboratory tests have shown that the plant’s active ingredients relax rabbit penile tissue by augmenting nitric oxide and PDE-5 activity. Other studies have demonstrated that injections of Epimedium extract directly into the penis of the rat result in an increase in the flow of blood to that organ. Icariin, the main active chemical compound in Epimedium, inhibits the activity of PDE-5, in a similar way as the pharmaceutrical drugs sildenafil, commercially known as Viagra® and vardfenafil (Levitra®) (Ning et al., 2006).

A recent study undertaken by Italian scientists modified the chemical structure of icariin and also investigated various other chemical substances derived from it. Inhibitory concentrations for PDE-5 similar to those of the prescription drug sildenafil could be reached. Additionally, the most potent PDE-5 inhibitor of this series was also a potent inhibitor of the enzymes phosphodiesterase-6 (PDE-6) and cyclic adenosine monophosphate-phosphodiesterase or cAMP-PDE (Dell'Agli et al., 2008).

Extracts of Epimedium have estrogenic action due to the presence of newly discovered potent phytoestrogens, non-steroidal plant compounds that have actions similar to those of mammalian female hormones (Yong et al., 2007). The plant’s compounds (including epimedin) have a cytotoxic action against certain cancer cell lines and possess immune-stimulating activities (Tang and Eisenbrand, 2011).

Safety / Precautions

  • The safety of this herb has not been adequately studied, especially during pregnancy and lactation.
  • Additionally, certain herbs that are sometimes combined with Epimedium, such as yohimbé bark, for example, may cause hypertension and mania in high doses.
  • Quality control in certain herbal supplements is sometimes lacking, so it is best to consult first with a qualified health provider before taking any product containing this herb.
  • There are no known studies regarding the potential herb-drug interactions between horny goat weed and prescription pharmaceuticals used to treat erectile dysfunction, such as sildenafil and vardenafil.
  • More research regarding the therapeutic use of this herb in humans is needed before it can be safely recommended for the treatment of erectile dysfunction.
  • For this reason, it is not recommended to take horny goat weed, or any other herb purported to treat impotence, along with the prescription medications mentioned above, without prior medical advice.

Before you decide to take any medicinal herb or herbal supplement, be sure to consult with a health care professional first. Avoid self-medication and self-diagnosis: Always be on the safe side!

References:

Dell'Agli M, Galli GV, Dal Cero E, Belluti F, Matera R, Zironi E, Pagliuca G, Bosisio E. Potent
inhibition of human phosphodiesterase-5 by icariin derivatives. J Nat Prod. 2008; 71(9):1513-7.

Mabberley D J. Mabberley’s Plant Book 3 rd ed.
London: Cambridge University Press; 2008; p. 309.

Ning H, Xin ZC, Lin G, Banie L, Lue TF, Lin CS. Effects of icariin on phosphodiesterase-5 activity
in vitro and cyclic guanosine monophosphate level in cavernous smooth muscle cells. Urology. 2006;
68(6):1350-4.

Tang W, Eisenbrand G. Handbook of Chinese Medicinal Plants Vol. 2.
New York: Wiley; 2011; pp. 496-502

Quattrocchi U. World Dictionary of Medicinal and Poisonous Plants.
Boca Raton, FL: CRC Press; 2012; pp. 77-78.

Yong EL, Wong SP, Shen P, Gong YH, Li J, Hong Y. Standardization and evaluation of botanical
mixtures: lessons from a traditional Chinese herb, Epimedium, with oestrogenic properties. Novartis
Found Symp. 2007; 282: 173-88.

Zhang S (editor). A Coloured Atlas of the Chinese Materia Medica Specified in the Pharmacopoeia
of the People’s Republic of China. Hong Kong: Joint Publishing Company; 1996; pp. 423-425.