Melanotan II Nasal Tanning Spray Risks: Dizziness, Nausea, Skin Cancer Business Insider Melanotan Tanning Peptides: Safe Use, Side Effects & How It Works Scientifically 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