Mk 677 (INN) Ibutamoren (developmental code names MK-677, MK-0677, L-163,191; former tentative brand name Oratrope) is a potent, long-acting, orally active, selective, and non-peptide agonist of the ghrelin receptor and a growth hormone secretagogue, mimicking the growth hormone (GH)-stimulating action of the endogenous hormone ghrelin. We have shown it to increase the secretion of several hormones,
