Viral 'Barbie drug' for tanning can cause brain swelling and even cancer, experts warn Dying for a tan: The rise in sunbed use with melanotan, the illegal nasal spray that boosts tan with serious side effects Irish Independent 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 You Should Avoid Using Nasal Tanning Sprays