Andarine (S-4) is an orally active, non-steroidal Selective Androgen Receptor Modulator (SARM) that binds selectively to androgen receptors (AR) in skeletal muscle and bone tissue. By mimicking the effects of endogenous testosterone, Andarine activates anabolic signaling pathways that stimulate protein synthesis, promote lean muscle growth, increase strength, and enhance bone density, while minimizing androgenic effects in non-target tissues such as the prostate and liver. Through its selective receptor modulation, Andarine supports fat metabolism and improves muscle endurance, making it effective for preserving lean mass during caloric deficits. It also contributes to accelerated recovery from muscle stress or injury by regulating gene expression involved in tissue repair, protein turnover, and cellular metabolism. In addition to its anabolic activity, preliminary studies suggest Andarine may positively influence overall body composition by promoting favorable shifts in muscle-to-fat ratio and improving metabolic efficiency. Its selective mechanism allows users to experience performance and aesthetic benefits similar to anabolic steroids without the systemic side effects typically associated with steroid use.