View of Association of tanning injection with hypercortisolism, hyperglycaemia and ketosis in type 1 diabetes mellitus British Journal of Diabetes 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 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 longer lasting than Melanotan II (Tan Jabs): Why They're Not Worth The Risk What is the 'Barbie drug' and should authorities be worried? ABC News