Melanotan II: Benefits and Side Effects_Chemicalbook Peptides are having a moment, but not all of them are harmless., One thats getting a lot of attention right now? Melanotan II., Its being used to achieve a tan from the inside, but what it 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 Doctors Say "Barbie Drug" Melanotan II Can Cause Brain Swelling Melanotan II (Tan Jabs): Why They're Not Worth The Risk