A number of natural herbal products for treating erectile dysfunction (ED) are available. Although these products do not contain sildenafil citrate, the active ingredient in Viagra, they may be effective. However, evidence supporting their success is largely anecdotal.
Yohimbe is derived from the bark of an African tree and is sold as an herbal supplement and in prescription form. According to a 2004 review by Douglas MacKay in the journal "Alternative Medicine Review," yohimbe has been shown in some but not all studies to be an effective treatment for impotence.
Horny Goat Weed
According to Drugs.com, the Chinese herb horny goat weed has aphrodisiac qualities that improves impotence; however, strong clinical evidence is lacking and the appropriate dosage is unclear.
The efficacy of ginkgo biloba in treating ED has been studied, primarily in men with sexual dysfunction associated with antidepressant use. According to MacKay's review, study results vary widely, with some showing a positive effect.
Red ginseng has also been studied as a natural source for sildenafil. Clinical trials cited by MacKay suggest that this plant is a moderately effective treatment. In a 2008 review of red ginseng studies published in the “British Journal of Clinical Pharmacology,” Dai-Ja Jang and colleagues also found some evidence of efficacy.
Though evidence exists for natural alternatives to sildenafil, many lack solid clinical evidence due to small study size or poor methodological quality. In addition, dosages of unregulated supplements vary widely, and Mayoclinic.com warns that some may cause dangerous side effects like low blood pressure. Discuss treatments with your doctor before experimenting.