Melanotan II: Tanning injections, nasal sprays harmful to health 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 Thinking about that tanning nasal spray? Don't. Unregulated nasal tanning sprays are being sold online, claiming to give you a sun kissed glow. But they're risky and illegal. According to the Chartered Trading Nasal Tanning Sprays: Unregulated Health Risks in the UK