Molecular Formula: C27H36N4O5S.CH4O3S
Molecular weight: 624.776
MK-677 also known as Ibutamoren, MK-0677, L-163,191 is a non-peptidic, potent, long-acting, orally-active, and selective agonist of the ghrelin receptor and a growth hormone secretagogue, mimicking the growth hormone (GH)-stimulating action of the endogenous hormone ghrelin.
It has been demonstrated to increase the release of, and produces sustained increases in plasma levels of several hormones including GH and insulin-like growth factor 1 (IGF-1), but without affecting cortisol levels.
MK677 has shown to sustain activation of GH-IGF-1 Axis and increase in lean body mass but no change in total fat mass or visceral fat. It is currently under development as a potential treatment for reduced levels of these hormones, such as in children or elderly adults with growth hormone deficiency and human studies have shown it to increase both muscle mass and bone mineral density, making it a promising therapy for the treatment of frailty in the elderly.