S-23 is an modern selective androgen receptor with the added interest in its potential for male hormonal contraceptive. It binds to the androgen receptor more strongly than older compounds such as  with a Ki of 1.7nM, and in animal studies it showed both a good ratio of anabolic to androgenic effects, and dose-dependent suppression of spermatogenesis with spontaneous recovery after cessation of research. 

S23 belongs to a class of research chemicals known as SARs, which stands for selective androgen receptor. These are highly anabolic compounds that signal your body to build muscle at a steroid raw powder like rate.

S23 is a powerful anabolic research chemical that many recreational users are taking to rapidly increase lean muscle mass.which some recreational users claim can even rival.