Afamelanotide (Melanotan I; [Nle4, D-Phe7]-α-MSH, CAS 75921-69-6) is a synthetic linear tridecapeptide analog of α-MSH (C78H111N21O19; ~1646.9 Da), sequence Ac-Ser-Tyr-Ser-Nle-Glu-His-D-Phe-Arg-Trp-Gly-Lys-Pro-Val-NH2. For research (RUO).