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 Experts lash use of popular social media sun tanning drug Melanotan The Risks of Fast Tanning 'Barbie Drug' Explained Ever Clinic Here's the part nobody explains when they're selling you the "Barbie drug." Melanotan 2 is a synthetic peptide that mimics alpha MSH a hormone your body already makes to tell your skin