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 Sun and Skin: From Burns to Melanoma, What Every Clinician Needs to Know and Share Melanoma induction by ultraviolet A but not ultraviolet B radiation requires melanin pigment Nature Communications Viral 'Barbie drug' for tanning can cause brain swelling and even cancer, experts warn