Peptide Dosage Chart: 20+ Peptides PeptidesExplorer Melanotan II Safety: Tanning Injection LIVV Natural 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 Melanotan II is a synthetic peptide that mimics the bodys natural melanocortin hormones, primarily activating receptors involved in skin pigmentation, appetite, and central nervous system signaling.