Proviron (Mesterolone) is a synthetic, orally effective androgen which does not have any anabolic characteristics. Proviron is used in school medicine to ease or cure disturbances eased by a deficiency of male sex hormones.

Proviron represents one of the oldest anabolic androgenic steroids. Many athletes, often use Proviron at the end of a steroid treatment in order to increase the reduced testosterone production. Proviron has no effect on the body's own testosterone production but-as mentioned in the beginning-only reduces or completely eliminates the dysfunctions caused by the testosterone deficiency. These are in particular impotence which is mostly caused by an androgen deficiency that can occur after the discontinuance of steroids and infertility which manifests itself in a reduced sperm count and a reduced sperm quality.

Proviron is therefore taken during a steroid administration or after discontinuing the use of the steroids, to eliminate a possible impotency or a reduced sexual interest.

Proviron is unfortunately cunsidered by many to be a useless and unnecessary compound. Proviron is also an estrogen antagonist which prevents the aromatization of steroids. Unlike the antiestrogen Tamoxifen which only blocks the estrogen receptors Proviron already prevents the aromatizing of steroids. Therefore gynecomastia and increased water retention are successfully blocked.

Since Proviron strongly suppresses the forming of estrogens no rebound effect occurs after discontinuation of use of the compound as is the case with. For this reason male athletes obtains more muscle hardness since the androgen level is increased and the estrogen concentration remains low. In particular, it is noted positively during the preparation for a competition when used in combination with a diet.

Since, Oligozoospermia and deficient Leydig-cell secretion may be the cause of infertility. With Proviron treatment, sperm count can be increased, the quality improved and, furthermore, a higher fructose concentration up to normal values can be achieved thus increasing the chances of procreation.