Men suffering from erectile dysfunction have the option of taking yohimbe or L-arginine instead of Viagra and other PDE-5 inhibitors. Yohimbe and L-arginine can increase penile blood flow, and they are often added to many natural sexual enhancement products. Yohimbe contains the powerful stimulant yohimbine, while L-arginine is an amino acid and nitric oxide precursor.
Yohimbe comes from the bark of a tree common to Africa. Yohimbe’s medicinal properties stem from the yohimbine present in its bark. While yohimbe is available in dietary supplements, yohimbine is a prescription drug in the United States. L-arginine is a semi-essential amino acid. While your body typically makes enough, you could need additional arginine if your body fails to produce the right amount of arginine on its own.
Mechanisms of Action
Like caffeine, yohimbe stimulates your nervous system. By stimulating the brain, during sexual situations it increases blood flow and signals to the penis. Yohimbe also works as a monoamine oxidase inhibitor, an antidepressant. L-arginine turns into nitric oxide which dilates blood vessels, including those in the penis. Because Viagra and other PDE-5 drugs also increase nitric oxide, some arginine makers claim it's a natural alternative to Viagra. Arginine, however, merely functions as a building-block for nitric oxide, while PDE-5 medications like Viagra increase nitric oxide by other mechanisms.
Yohimbine and L-arginine may help men with erectile dysfunction, or ED, though doubts of their effectiveness persist. MedlinePlus says yohimbine and L-arginine are “possibly effective” for treating ED. A British meta-analysis of seven yohimbine clinical trials concluded it was more effective than a placebo. A French study, published in a 2002 issue of “European Urology,” found that the combination of yohimbine and L-arginine improved erectile function.
Yohimbe is sold as an herbal supplement, usually in capsules. Manufacturers often combine it with other ingredients such as L-arginine and other herbs purported to increase sexual performance. ED sufferers probably should consider prescription yohimbine, which has been studied and tested extensively, rather than herbal preparations which haven't. Countless supplement-makers sell L-arginine as powder or pills. High doses -- at least 5 grams daily -- are typically recommended for ED treatment.
MedlinePlus.com classifies herbal yohimbe as “possibly unsafe” because it can cause potentially life-threatening side effects, including seizures and cardiovascular problems. MedlinePlus considers prescription yohimbine less dangerous, but it can also cause these problems along with anxiety, dizziness and tremors. Yohimbine interacts with a number of medications, especially those for mental health. L-arginine can decrease blood pressure, so it may interact with blood pressure medications and drugs like Viagra. You may also experience upset stomach, especially at greater doses.