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.
Like other AAS, boldenone is an agonist of the androgen receptor (AR).  The activity of boldenone is mainly anabolic , with a low androgenic potency. Boldenone will increase nitrogen retention, protein synthesis, increases appetite and stimulates the release of erythropoietin in the kidneys.  Boldenone was synthesized in an attempt to create a long-acting injectable metandienone , for androgen deficiency disorders. Boldenone acts similar to metandienone with fewer adverse androgenic effects. [ medical citation needed ] Although commonly compared to nandrolone , boldenone lacks progesterone receptor interaction and associated progestogenic side effects.