Melanotan What It Is and Its Relation to Skin Cancer 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 It doesn't take much to fall down the Barbie Drug rabbit hole. In self tanner subreddits and on TikTok Shop, the tanning injectionaka Melanotan IIis marketed as a self tanner alternative that works by Melanotan What It Is and Its Relation to Skin Cancer Viral 'Barbie drug' for tanning can cause brain swelling and even cancer, experts warn