Ostarine (MK-2866) is one of the most extensively studied SARMs and the first to reach advanced clinical trials. It was initially developed to treat and prevent muscle wasting in cancer and osteoporosis patients. There are ongoing clinical and preclinical trials to test the efficacy of Ostarine in prevention of muscle atrophy, cachexia and sarcopenia.
MK-2866 binds to AR (androgen receptor) and promotes anabolic activity preferentially in the bone and muscle. MK-2866 allows for muscle growth by allosterically activating AR and thus altering gene expression and protein synthesis. MK-2866 exerts its anabolic effects almost exclusively in muscle tissue and minimizes muscle atrophy, most notably during recovery periods from surgery and injury. This suggests MK-2866 has myriad potential uses, and it has been shown to be highly effective at gaining and maintaining lean body mass in humans clinically.