S-23

S-23 is an investigational, orally active, nonsteroidal selective androgen receptor modulator (SARM) developed by GTX, Inc. It binds to the androgen receptor with high affinity, acting as an agonist to promote anabolic effects in muscle and bone tissue. It was primarily investigated as a potential male hormonal contraceptive due to its ability to induce dose-dependent and reversible suppression of spermatogenesis in animal studies. Preclinical research also indicated its potential for increasing lean body mass and bone mineral density while minimizing androgenic side effects on tissues like the prostate. S-23 is not approved for human use by regulatory bodies like the FDA and is banned by anti-doping agencies.