(CNN)- Pfizer announced Monday it is setting up its own site to sell Viagra online.
The move is designed battle the sale of counterfeit versions of the drug.
Most online sites that sell medications are not legitimate, according to Pfizer.
A 2011 study by its security department found that counterfeit pills have only a fraction of the active ingredients advertised.
Viagra is Pfizer's most counterfeited product.
The new site is Vagra.com.
