Muira puama is a bush native to the Brazilian Amazon rain forest. Its bark and roots have been used traditionally for a variety of medicinal purposes, including impotence in men, loss of libido in women, nerve problems (including paralysis and tremor), anxiety, digestive problems, and arthritis.

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Explorers brought muira puama to Europe, where it became popular primarily as a treatment for impotence. However, there has been no reliable scientific evaluation of the effectiveness of this herb.

One study is commonly cited as showing that muira puama is more effective for impotence than the drug yohimbine (from the herb yohimbe).1 However, this study actually shows nothing at all. It was an open trial, in which all participants took muira puama. The researchers simply compared the benefits seen in this trial to the benefits seen in other trials in which people took yohimbine. From a scientific perspective, this is not permissible. The placebo effect is strong, and varies from study to study. One can assume without even performing the experiment that if men with sexual dysfunction are given a treatment that they believe might help them, they will be helped. To determine whether muira puama is helpful for impotence would require a double-blind, placebo-controlled study. To determine whether it is more effective than yohimbine would require a double-blind study in which some people took muira puama and some took yohimbine. Since no double-blind studies of muira puama have been reported at all, use of this herb has to be regarded as entirely speculative. (For more information on why double-blind studies are essential, see Why Does This Database Rely on Double-blind Studies?)

Weak evidence hints that muira puama may be helpful for enhancing mental function by increasing brain levels of acetylcholine, but this evidence is far too preliminary to indicate effectiveness.2,3

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Muira puama is generally taken in the form of a liquid alcohol extract. Follow label instructions for dosage.

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From what limited evidence that is available, it does not appear that use of muira puama commonly causes significant side effects. However, comprehensive formal safety evaluation has not been conducted. For this reason, muira puama should not be used by pregnant or nursing women, young children, or individuals with severe liver or kidney disease.