No, you don't need the 'Barbie drug' to tan, whatever TikTok says. Here's why melanotan II is so risky Melanotan II PERMANENTLY Darkened My Skin! 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: Tanning, Sexual Health Benefits, & Safety Concerns Warning issued over increased use of 'Barbie drug'