Mesterolone is a synthetic, orally effective androgen but without any anabolic characteristics, so technically it does not fit into the category of anti-estrogens, however it is quite effective for that purpose. It was traditionally used in school medicine to ease or cure disturbances caused by a deficiency of male sex hormones. Many athletes and bodybuilders often use Proviron, for this reason, as an anti-Estrogen. It is completely compatible with all popular anabolic steroids. Also, many athletes often use Proviron at the end of their steroid cycle to increase the reduced testosterone production. This, however may not be a perfect idea because Mesterolone has no effect on the own testosterone production of the body but as mentioned before, it only reduces or completely eliminates the dysfunctions caused by the deficiency of testosterone.
Proviron is normally taken during a steroid cycle or after discontinuing the use of the steroids, to eliminate a possible impotency or a reduced sexual interest. This, however does not contribute to the maintenance of strength and muscle mass after the treatment. There are other better suited compounds for this (see HCG and Clomid) for those reasons, so Mesterolone is unfortunately considered by some users to be a useless and unnecessary drug, however you should be aware that it is still a popular anti-estrogen which means it will prevent the aromatization of steroids. Unlike the antiestrogen Nolvadex which only blocks the estrogen receptors, Proviron already prevents the aromatizing of steroids. Therefore gynecomastia and increased water retention are successfully blocked.
Traditionally it was common for bodybuilders to take one 25 mg tablet each day over several weeks, sometimes even months, in order to appear hard all year round. This was especially important for athletes appearances, seminars and photo sessions. Today Clenbuterol is usually taken over the entire year since possible virilization symptoms cannot occur which is not yet the case with Proviron. Since Proviron is very effective, male athletes usually need only 50 mg/day and not more, but in many cases 25 mg per day is sufficient. When combining Proviron with Nolvadex (50 mg Proviron/day and 20 mg Nolvadex/day) this will lead to an almost complete suppression of estrogen.