S23 is an orally bioavailable, non steroidal selective androgen receptor modulator (SARM) that has been proven to increase lean muscle and bone tissue while being tissue selective (unlike traditional steroids).

Studies and user reports suggest that S23 is the closest SARM to steroids, with a few key differences, such as decreased prostate size. Other user reports suggest that S23 is a much more powerful version of S4 (Andarine) and the benefits of this SARM falls in the category of hardening muscle and creating a grainier aesthetic look.