Herbal viagra is a name that can be given to any herbal product advertised as treating erectile dysfunction. The name "herbal viagra" is taken from the brand name Viagra, under which drug company Pfizer sells sildenafil citrate, a drug that is used to treat erectile dysfunction. Viagra has become a generic term for many people discussing drugs designed to treat erectile dysfunction.
There are many different products advertised as herbal viagra, but with varying ingredients. The most popular herbs are epimedium (horny goat weed), damiana, ginseng, ginkgo, yohimbe, saw palmetto, maca, Muira puama, and Tribulus terrestris. There are no clinical trials or scientific studies that support the effectiveness of any of these ingredients for the treatment of erectile dysfunction.
Herbal viagras, contrary to what the name suggests, do not normally contain sildenafil citrate. However, synthetic chemical compounds similar to sildenafil have been found as adulterants in many supplements which are sold as herbal viagra or "natural" sexual enhancement products. The United States Food and Drug Administration has warned consumers that any sexual enhancement product that claims to work as well as prescription products is likely to contain such a contaminant.
Herbal viagras often carry a number of dangerous side effects. Primarily, they cause abnormally low blood pressure and can restrict blood flow to vital organs. There is also evidence to suggest some preparations may be toxic if taken in larger doses. Additional side effects and dangers of common herbal viagra adulterants, such as sulfoaildenafil and others, are unknown because these ingredients have not had thorough review in human clinical trials.
Herbal viagra is predominantly sold through the internet, and in 2003 approximately 4% or 1 in 25 of all e-mail messages sent offered herbal viagra, genuine pharmaceuticals, and other herbal remedies. Herbal viagra is claimed to boost a male's sex drive and increase stamina, and provide a longer lasting and harder erection.