Does the MOTC (Melanotan II) peptide injection accumulate or stop being effective once stopped? How to Give Yourself a Subcutaneous Injection Using a Prefilled Syringe Memorial Sloan Kettering Cancer Center 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 PDF) Use of melanotan I and II in the general population