Health Do Peptides Darken Skin? Risks and Benefits Explained by Dr Natalie Singh - Health Editor July 18, 2026 by Dr Natalie Singh - Health Editor July 18, 2026 Melanotan II, a synthetic peptide often marketed as a “tanning injection,” carries significant health risks and lacks approval from the U.S. Food and Drug Administration (FDA) for any therapeutic use. … 0 FacebookTwitterPinterestEmail