Melanotan 2 (@melanotanii) Facebook 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 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 cells to Dangerous 'Barbie drug' Melanotan II sparks crackdown on social media influencers ABC News