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 A peptide that makes you tan. Sounds great. What could go wrong? When its activating your melanocytes to increase pigment in your skin, it may also be causing cancer melanoma. Ive had patients have Melanotan What It Is and Its Relation to Skin Cancer Melanotan II Wikipedia