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 You Should Avoid Using Nasal Tanning Sprays MELANOTAN 2., 10 Avoid nasal tanning sprays or nasal tanners entirely. These products promise an all over tan without sun exposure but they are unregulated, can be unsafe, and contain potentially risky substances like Melanotan 2.