What is Swiss Chems MK677 Ibutamoren? MK-677, also called ibutamoren or ibutamoren mesylate, is a peptide that belongs to the growth hormone secretagogues team (GHSR). It works by mimicking the motion of your hunger hormone ghrelin. It binds to 1 of The expansion hormone secretagogue receptors (GHSR) during the brain, helping maximize growth hormon