Purity >97% by HPLC. Cyclic MSH analogue that is a potent full agonist of the melanocortin 3 (MC3) and melanocortin 4 (MC4) receptors. I.c.v administration inhibits feeding in four different mouse models of hyperphagia. A valuable tool for the study of the agouti obesity syndrome and of the role of melanocortinergic neurons in feeding.