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Horny Goat Weed

What is it?

Horny goat weed is an herb. The leaves are used to make medicine. As many as 15 horny goat weed species are known as “yin yang huo” in Chinese medicine.

Horny goat weed is used for weak back and knees, joint pain, osteoarthritis, mental and physical fatigue, memory loss, high blood pressure, heart disease, bronchitis, liver disease, HIV/AIDS, polio, a blood disorder called chronic leucopenia, viral infections of the heart, bone loss after menopause, weak bones (osteoporosis), and as a tonic.

Some men use horny goat weed for sexual performance problems including erectile dysfunction (ED) and involuntary ejaculation. It is also used to arouse sexual desire.

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...

  • Osteoporosis. Developing research shows that taking a specific extract of horny goat weed for 24 months seems to decrease bone loss of the spine and hip in women who have passed menopause. This particular extract, made by Tong Ji Tang Pharmacal Company in China, contains phytoestrogens (specifically containing 60 mg of icariin, 15 mg of daidzein, and 3 mg of genistein). These chemicals act somewhat like the hormone estrogen.
  • Postmenopausal conditions. Early research suggests that taking horny goat weed water extract for 6 months can decrease cholesterol and increase estradiol levels in postmenopausal women.
  • Erectile dysfunction (ED).
  • Ejaculation problems.
  • Sexual problems.
  • Fatigue.
  • Memory loss.
  • High blood pressure.
  • Heart disease.
  • Liver disease.
  • Bronchitis.
  • Joint pain.
  • HIV/AIDS.
  • Other conditions.
More evidence is needed to rate horny goat weed for these uses.

How does it work?

Horny goat weed contains chemicals which might help increase blood flow and improve sexual function. It also contains phytoestrogens, chemicals that act somewhat like the female hormone estrogen, that might reduce bone loss in postmenopausal women.

Are there safety concerns?

Horny goat weed extract is POSSIBLY SAFE when taken by mouth, appropriately. A specific extract of horny goat weed containing phytoestrogens has been taken by mouth for up to 2 years. Also, a different extract of horny goat weed containing icariin has been taken by mouth for up to 6 months.

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 arrhythmia has also been reported in a man who took horny goat weed in a commercial product used for sexual enhancement. Research also shows that a specific multi-ingredient commercial product (Enzyte, Berkeley Premium Nutraceuticals) that contains horny goat weed might cause abnormal heart beats when measured by an electrocardiogram. These changes might increase the chance of having a heart arrhythmia. However, since these products contain multiple ingredients, it is not clear if these effects are caused by horny goat weed or other ingredients.

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 slows blood clotting and might increase the risk of bleeding. However, it is not known if this is a big concern. 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. Horney 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 slows blood clotting and might increase the risk of bleeding during surgery.

Are there interactions with medications?

Moderate
Be cautious with this combination.
Estrogens
Horny goat weed might have some of the same effects as estrogen and can 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 for high blood pressure (Antihypertensive drugs)
Horny goat weed seems to decrease 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?

The appropriate dose of horny goat weed depends on several factors such as the user's age, health, and several other conditions. At this time there is not enough scientific information to determine an appropriate range of doses for horny goat weed. Keep in mind that natural products are not always necessarily safe and dosages can be important. Be sure to follow relevant directions on product labels and consult your pharmacist or physician or other healthcare professional before using.

Other names

Barrenwort, Épimède, Épimède à Grandes Fleurs, Épimède du Japon, Epimedium, Epimedium acuminatum, Epimedium brevicornum, Epimedium grandiflorum, Epimedium Grandiflorum Radix, Epimedium koreanum, Epimedium macranthum, Epimedium pubescens, Epimedium sagittatum, Epimedium violaceum, Epimedium wushanese, Herba Epimedii, Herbe Cornée de Chèvre, Hierba de Cabra en Celo, Japanese Epimedium, Xian Ling Pi, Yin Yang Huo.

Methodology

To learn more about how this article was written, please see the Natural Medicines Comprehensive Database methodology.

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Last reviewed - 04/08/2015