MW: 6,042 Da. Purity >97.0% as determined by: (a) Analysis by RP-HPLC. (b) Analysis by SDS-PAGE. Description: The molecular formula of Melanotan-II is C50H69N15O9. It has the amino acid sequence of Ac-Nle-cyclo [Asp-His-D-Phe-Arg-Trp-Lys]-NH2 and a molecular weight of 1024.2 Dalton. The CAS Number is 121062-08-6.Introduction: Melanotan and Melanotan-II are both analogs of the peptide hormone alpha melanocyte stimulating hormone (a-MSH) that tend to induce skin tanning. Unli