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Mesterolone also known as Proviron is an androgen use to treat for example age-related erectile dysfunction, which is often based on a too low testosterone levels. In the bodybuilding scene, it is popular as an estrogen antagonist and helps athletes who area using anabolic steroids to counteract Gynecomastia.

Mesterolone is used to convert some of the steroids to suppress estrogen and therefore the Gynecomastia (25-50mg / day). This effect however, is highly questionable and not detected in any form. The anti-estrogenic effect of Mesterolone is based much on that it reacts strongly with the androgen binding protein bodies (SHBG sex hormone binding globulin) and may displace other Testosterone from existing bonds. This means that the testosterone is released in a very short time.

Mesterolone is an estrogen antagonist that inhibits the aromatization of steroids. In contrast to the anti-estrogen drug Tamoxifen citrate that only blocks the estrogen receptors, Mesterolone prevents from scratch the aromatization of steroids.

Gynecomastia and increased water retention is reliably counteracted.

Since Proviron strongly suppresses estrogen formation, it comes to no rebound effect after the discontinuation of the drug e.g. Tamoxifen citrate can be the case where an aromatization of steroids will not be prevented.

It is fair to say that the evil Mesterolone (flavoring) tackles the roots, while only the symptoms can be combated with Tamoxifen citrate.

Many male athletes use Mesterolone preparations.

Doping Information:

Mesterolone can still be detected 6 weeks after the last application.

Application / dosage:

Women: 1 tablet containing 25 mg per day
Men: 1-3 tablets with each tablet containing 25mg per day

The dosage information here do not follow the dosage recommendations prescribed by a physician or medical advice. It’s information used by bodybuilders who are using these drugs or have used these drugs. The dosages are not to be considered as generally applicable. If you wish to use steroids, ask a doctor or pharmacist .

Black market prices / availability:

A box of Mesterolone with 20 tablets containing 25 mg is available on the black market at 7-8 euros.

Mesterolone is well available on the black market.


Mesterolon, Mesterolonum, Androviron, Testiwop, Mesteranum

Brandnames / Producer:

Proviron / Schering

Chemical Information:Mesterolon Mesterolone - Formel

Molecular Formula: C20H32O2
Molecular Weight: 304.47 g / mol
Monoisotopic Mass:304.240234 Da
Half-life: 12 hours


(1S,5S,8R,9S,10S,13S,14S,17S)-17-hydroxy-1,10,13-trimethyl-1,2,4,5,6,7,8,9,11,12,14,15,16,17-tetradecahydrocyclopenta[a]phenanthren-3-one; (5Z,8Z,11Z,14Z)-icosa-5,8,11,14-tetraenoic acid