S23 is a selective androgen receptor modulator (SARM) currently under development for potential use as a male hormonal contraceptive.
It is still in the preclinical stage of development, meaning it has only been tested on animals, not humans.
S23 exhibits a high affinity for the androgen receptor with tissue selective anabolic effects in muscle in bone, with relatively less stimulation of the prostate, seminal vesicles, and other androgen affected tissues.
The closer a SARM is to 100% the closer it is to complete absorption after oral dosing.
This means that S23 can be administered orally, as opposed to requiring injections to achieve maximal blood serum concentration levels, which is obviously advantageous when it comes to ease of use and adoption.
S23 has become increasingly popular in the recreational bodybuilding community for its potent muscle building and body recomposition effects.