Your body already makes a hormone that tells your skin to tan. Melanotan 2 is a synthetic peptide engineered to mimic that hormone but in a version that's more potent and Eruptive Dysplastic Nevi Following Melanotan Use Actas Dermo Sifiliogrficas Eruptive Dysplastic Nevi Following Melanotan Use Actas Dermo Sifiliogrficas Emerging Threat: Melanotan, Repackaging, and Online Sales Teen Boys and Young Men Are Injecting Peptides in Search of Perfection WSJ