Melanotan II Skin Pigmentation & Libido Imagine just wanting to be jacked and tan and you end up like this? Melanotan II is a peptide that increases the melanin in your skin and can give men a boner that What Is Melanotan, the So Called Barbie Peptide? PS Beauty 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 MELANOTAN I PEPTIDE 10MG VIAL UMBRELLA Labs