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 Viral 'Barbie drug' for tanning can cause brain swelling and even cancer, experts warn PDF] Changes of melanocytic lesions inducedby Melanotan injections and sun bed use ina teenage patient with FAMMM syndrome Semantic Scholar Melanotan II (Tan Jabs): Why They're Not Worth The Risk Melanotan & Tanning Injections: Safe or Risky?