MK-677, also called ibutamoren, is an orally-active small-molecule growth hormone secretagogue. A non-peptide agonist of the ghrelin receptor and chemically indistinguishable from GHRP-6, it has a substantial effect on GH release without affecting cortisol.
With a favorable safety profile to date, MK-677 has been shown to promote lean body mass production, bone health, neurologic function, and sleep quality. It is actively being investigated for potential benefits relating to body composition, bone density, sleep, and longevity.