Enobosarm (Ostarine / MK-2866)

Mechanism of Action

Enobosarm (MK-2866) is a non-steroidal selective androgen receptor modulator (SARM) that binds the androgen receptor with high affinity and tissue selectivity. Unlike steroidal androgens, enobosarm does not require 5-alpha reduction and does not aromatize to estrogen. It functions as a full agonist at AR in skeletal muscle and bone, promoting anabolic effects (increased lean body mass, bone mineral density), while acting as a partial agonist or antagonist in androgenic tissues (prostate, sebaceous glands), resulting in reduced androgenic side effects. Clinical Phase II trials have demonstrated dose-dependent increases in lean body mass in cancer cachexia and elderly sarcopenia populations.

Evidence Level

Clinical Trial - Human

8 studies published