Melanotan II (Tan Jabs): Why They're Not Worth The Risk Catit Cat Wet Food Recipes Chick, Senior 3oz Petsense 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 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 Melanotan II (Tan Jabs): Why They're Not Worth The Risk