Viral 'Barbie drug' for tanning can cause brain swelling and even cancer, experts warn 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 II is a peptide that supports melanin production meaning your glow can start from the inside out (without living out in the sun or tanning beds). Our WCC nurses Melanotan II and NAD+ Stack: Summer Tanning Experiment Melanotan Tanning Peptides: Safe Use, Side Effects & How It Works Scientifically