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 Scarlet Red Color Depositing Treatment Mask Semi Permanent Hair Color by Overtone Overtone Color 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 Understanding Red Hair: Colors, Tones, and Comparisons KLAIYI