Melanotan What It Is and Its Relation to Skin Cancer Melanotan is not a tan. It's an unregulated peptide with real risk. As a dermatologist, here's the reality: It has been linked to new and changing moles including cases of Viral 'Barbie drug' for tanning can cause brain swelling and even cancer, experts warn What is melanotan and why is it so dangerous? Mucosal melanocytic macules MD breaking down Melanotan II Part 2 of my peptide series. The research, the risks, the reality. Long term safety data? Nonexistent.