what's Swiss Chems MK677 Ibutamoren? MK-677, also referred more info to as ibutamoren or ibutamoren mesylate, can be a peptide that belongs to the growth hormone secretagogues group (GHSR). It works by mimicking the action from the hunger hormone ghrelin. It binds to at least one of The expansion hormone secretagogue receptors (GHSR) from the brain