Melanotan II: Tanning, Sexual Health Benefits, & Safety Concerns 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 Melanotan II is the product that's been dubbed the "Barbie drug" on social media, and promises to give users a tan without the sun but it can have serious side effects including, in rare cases, Dermatologists are sounding the alarm on TikTok famous nasal tanning sprays