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.
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Medica. Revised Edition, Seattle: Eastland Press, 1992.
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the concentration of plasma middle molecular substances and sulfhydryl group of
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[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
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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
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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.
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HL-60 cells. Zhonghua Zhong Liu Za Zhi 1997;19:53–5 [in Chinese].
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and (-)-syringaresinols separated by chiral HPLC in PC12h and Neuro2a cells. Biol Pharm
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compound TCM agent containing ant extractive in animal models. Zhongguo Zhong Yao Za
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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.
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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
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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].