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 I (MT I) MCR Agonist MedChemExpress Change in moles linked to use of unlicensed sun tan jab The BMJ Melanotan vs. Astaxanthin for Glowing Skin Who's tan is reay for summer. This peptide can help.