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 Natural red hair color is primarily caused by variants in the MC1R (melanocortin 1 receptor) gene, which regulates melanin production in the body. These variants favor the production of reddish yellow pheomelanin over Matrix's Top 3 Red Hair Colors For Fall SalonCentric Using Melanotan to Prevent Polymorphous Light Eruption aka SUN POISONING Natural Kaos Reduced MC4R signaling alters nociceptive thresholds associated with red hair Science Advances