Proviroxyl with its active substance Mesterolone represents an estrogen antagonist meant to prevent the aromatization of steroids. It is classified as an androgenic steroid and anti-aromatization prescription drug.
Proviroxyl provide muscles more hardness because of the high androgen levels and the low level of estrogen. Since Proviroxyl is considered a weak anabolic, it is more popular for its ability to prevent gyno and fluid retention. However it is well known as a "helper" steroid.
Unlike almost all other orals, Proviroxyl is not hepatotoxic, as it is not 17-alkylated. The most common complaint with Proviroxyl by male users is erectile dysfunction, specifically prolonged and frequent erections. The potential side effect for female users with Proviroxyl is disruption of menstrual cycles.