Viral 'Barbie drug' for tanning can cause brain swelling and even cancer, experts warn It's a week of trending media talk about the dangers of Melanotan. I remember fielding a media interview about Melanotan 7 8 years ago. This trend has been around for a while, but 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 Emerging Threat: Melanotan, Repackaging, and Online Sales