What is it?
Horny goat weed is commonly used by mouth for sexual performance problems, such as erectile dysfunction (ED) and low sexual desire. It is also used for weak back and knees, joint pain, arthritis, mental and physical fatigue, and memory loss along with many other conditions. But there is limited scientific research to support any of these uses.
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. Taking a specific extract of horny goat weed for 24 months in combination with calcium supplements decreases bone loss of the spine and hip in women who have passed menopause better than taking calcium alone. Chemicals in the extract act somewhat like the hormone estrogen.
- Postmenopausal conditions.Taking horny goat weed water extract for 6 months can decrease cholesterol and increase estrogen levels in postmenopausal women.
- Ejaculation problems.
- Erectile dysfunction (ED).
- Heart disease.
- High blood pressure.
- Joint pain.
- Liver disease.
- Memory loss.
- Sexual problems.
- Other conditions.
How does it work?
Are there safety concerns?
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 rhythm problem has also been reported in one man who took horny goat weed in a commercial product used for sexual enhancement. A specific multi-ingredient commercial product (Enzyte, Berkeley Premium Nutraceuticals) that contains horny goat weed might cause abnormal heart beats. These changes might increase the chance of having a heart rhythm problems. A case of liver toxicity has been reported in a man who took this same product (Enzyte, Berkeley Premium Nutraceuticals). However, since this product contains multiple ingredients, it is not clear if these effects are caused by horny goat weed or other ingredients. In the case of liver toxicity, it's possible that the side effect was an abnormal reaction that would be unlikely to occur in other patients.
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 might slow blood clotting. This might increase the risk of bleeding. 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. Horny 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 might slow blood clotting. This might increase the risk of bleeding during surgery. Stop taking horny goat weed at least 2 weeks before surgery.
Are there interactions with medications?
- Horny goat weed might have some of the same effects as estrogen and might 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 changed by the liver (Cytochrome P450 1A2 (CYP1A2) substrates)
- Some medications are changed and broken down by the liver. Horny goat weed might decrease how quickly the liver breaks down some medications. Taking horny goat weed along with some medications that are changed by the liver might increase the effects and side effects of some medications. Before taking horny goat weed, talk to your healthcare provider if you take any medications that are changed by the liver.
Some of these medications that are changed by the liver include caffeine, clozapine (Clozaril), cyclobenzaprine (Flexeril), fluvoxamine (Luvox), haloperidol (Haldol), imipramine (Tofranil), mexiletine (Mexitil), olanzapine (Zyprexa), pentazocine (Talwin), propranolol (Inderal), tacrine (Cognex), theophylline (Slo-bid, Theo-Dur, others), zileuton (Zyflo), Zolmitriptan (Zomig), and others.
- Medications changed by the liver (Cytochrome P450 2B6 (CYP2B6) substrates)
- Some medications are changed and broken down by the liver. Horny goat weed might decrease how quickly the liver breaks down some medications. Taking horny goat weed along with some medications that are broken down by the liver can increase the effects and side effects of some medications. Before taking horny goat weed, talk to your healthcare provider if you take any medications that are changed by the liver.
Some medications that are changed by the liver include bupropion (Wellbutrin), cyclophosphamide (Cytoxan), dexamethasone (Decadron), efavirenz (Sustiva), ketamine (Ketalar), methadone (Dolophine), nevirapine (Viramune), orphenadrine (Norflex), phenobarbital, sertraline (Zoloft), tamoxifen (Nolvadex), valproic acid (Depakote), and numerous others.
- Medications for high blood pressure (Antihypertensive drugs)
- Horny goat weed might lower 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?
To learn more about how this article was written, please see the Natural Medicines Comprehensive Database methodology.
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