S-23
Muscle Growth & Body CompositionAlso known as: S23, SARM S-23
Mechanism
S-23 is one of the most potent SARMs studied, with strong anabolic effects on muscle and bone. Uniquely, it has been investigated as a potential male hormonal contraceptive because it suppresses FSH and LH to near-zero levels at effective doses, causing reversible infertility in animal studies. It is considered too suppressive for casual use.
Technical detail
S-23 is a non-steroidal SARM with very high AR binding affinity and full agonist activity in muscle tissue, producing anabolic effects comparable to dihydrotestosterone in preclinical models. At effective anabolic doses, it profoundly suppresses gonadotropins (FSH, LH) and produces reversible azoospermia in rats, leading to investigation as a male contraceptive agent. Spermatogenesis recovered fully upon cessation. Its potent suppression of the HPG axis distinguishes it from more selective SARMs.