According to a 2009 paper authored by GTx, "Readers are cautioned to note that the name ostarine is often mistakenly linked to the chemical structure of [S-4], which is also known as andarine . The chemical structure of ostarine has not been publicly disclosed."  While GTx has not formally disclosed the structure of enobosarm, the chemical composition of enobosarm is revealed in patent databases such the WIPO  and discussed by Zhang et al., 2009 in the primary literature.  Various SARM chemotypes exist (aryl propionamides, quinolines , quinolinones, bicyclic hydantoins), though aryl propionamides such as enobosarm, andarine/S-4, and S-23 represent some of the most advanced putative therapeutics under investigation.  In terms of atom connectivity, enobosarm differs from andarine by cyano substitutions on the phenyl rings as it replaces both the nitro and acetamido moieties.
Non-medical users of anabolic steroids often “stack” different anabolic steroids over the course of a “cycle” of use. They also administer various ancillary drugs and substances to enhance the desired effects of anabolic steroids or to minimize adverse side effects. The most common liquid (injectable) anabolic steroids encountered in these cases are (oil-based) esters of testosterone (., testosterone cypionate, testosterone enanthate, and testosterone propionate, and a blend of testosterone esters called Sustanon 250) or nandrolone (., nandrolone decanoate). Also popular are Equipoise (boldenone undecylenate) and trenbolone acetate and trenbolone enanthate, as well as the water-based injectable Winstrol (stanozolol). Popular oral anabolic steroids include methandrostenolone (Dianbol), oxandrolone (Anavar) and oxymetholone (Anadrol 50).
As a bulking agent, the effects of Masteron will prove to be rather weak. It is possible the hormone could provide gains in mass similar to Primobolan (which wouldn't be that strong either) if the total dose was sufficiently high. However, the relative gain in size will be moderate with many anabolic steroids being far more suited for this period of steroidal supplementation. Masteron does not aromatize and is not estrogenic; in fact, it shows anti-estrogenic traits in the body and binds to aromatase instead of other substrates. This is why it has been effective in the treatment of breast cancer.