Dromostanolone, marketed as Masteron, is a synthetic derivative of DHT. As you may know, DHT binds more strongly to the AR than testosterone but does not have an effect in muscle tissue because it is deactivated by 3-alpha hydroxysteroid dehydrogenase. The methyl group at the 2nd position allows dromostanolone to stay active in muscle tissue by disallowing deactivation by this enzyme to some degree, however, since Dromostanolone is converted primarily to the 2-methyl androsterone and 3-alpha diol derivatives there is still considerable deactivation by 3-alpha hydroxysteroid dehydrogenase1. The presence of the 2-methyl group does reduce potency of dromostanolone compared to DHT but only to about the level of testosterone. Since dromostanolone is already 5-alpha reduced, it is not converted any further. Therefore it is equipotent or slightly less potent in skeletal muscle compared to prostate, hair follicles etc.
This steroid is not prone to aromatization due to the 5-alpha reduction. Additionally, 5-alpha reduced steroids have been shown to have anti-aromatase activity. Dromostanolone, like DHT, binds strongly to SHBG and can displace bound estrogen into circulation which can result in delayed gynecomastia when one goes “off” of this steroid. No binding to progesterone or glucocorticoid receptors has been shown with this steroid. Dromostanolone is traditionally injected as a propionate ester requiring it to be injected every two or three days. It is a painful injection resulting in swelling and soreness.
There are no legitimate producers of dromostanolone propionate at this time, only underground suppliers. I would not be surprised to see different esters of dromostanolone show up on the black market and there have been some reports of oral dromostanolone being sold. Though many consider this steroid to be similar to DHT and expect side effects to be similar, dromostanolone is actually somewhat less harsh than DHT and more potent androgens. Its potency is similar to testosterone but without the conversion to estrogen which is demonstrated in its anabolic to androgenic ratio (about 3:1). Dromostanolone has build shown to build up red blood cells with a similar potency to oxymetholone2. Among users, this drug is known as a “hardener” because it loads water into the muscle without subcutaneous water retention (edema) resulting in a hard-looking physique. Dromostanolone is also known for its positive effects on strength.
1. Schanzer W: Metabolism of anabolic androgenic steroids. Clin Chem. Jul;42(7):1001-20, 1996
2. Sanchez-Medal L, Gomez-Leal A, Duarte L, Guadalupe Rico M. Anabolic androgenic steroids in the treatment of acquired aplastic anemia. Blood. 34(3):283-300, 1969
Adapted with permission from Seth Robert’s Anabolic Pharmacology, all rights reserved.