You Should Avoid Using Nasal Tanning Sprays 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 Melanotan II A Sun Kissed Look, and a Confident You. 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 Tanning Peptides: Safe Use, Side Effects & How It Works Scientifically IMB issues warning over tanning injections at salons or bought on internet The Irish Times