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 Melanotan is not a tan. It's an unregulated peptide with real risk. As a dermatologist, here's the reality: It has been linked to new and changing moles including cases of Australia's health regulator has issued an urgent alert against Melanotan a dangerous tanning product. "This stuff that people are getting is unlicensedand off the black market." Dr Greg Goodman