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 Nitisinone increases melanin in people with albinism National Institutes of Health (NIH) Viral 'Barbie drug' for tanning can cause brain swelling and even cancer, experts warn HPRA Warns of Dangerous Melanotan 2 in Tanning Products Obelis Group