Source comparison
Conclusion: MC1R Dominance vs MC4R Selectivity in Pigmentation Biology
Melanotan 2 and PT-141 are structurally near-identical melanocortin analogues whose single amino acid difference (Arg¹⁰ vs Lys¹⁰) produces a 10-fold MC1R affinity advantage for MT-II — creating meaningfully distinct pigmentation research pharmacologies. MT-II,
This comparison does not assign a generated winner or score.
- Melanotan 2 and PT-141 are structurally near-identical melanocortin analogues whose single amino acid difference (Arg¹⁰ vs Lys¹⁰) produces a 10-fold MC1R affinity advantage for MT-II — creating meaningfully distinct pigmentation research pharmacologies. MT-II, with MC1R Ki ~0.3 nM, produces 2.3× greater melanin production, 1.9× greater tyrosinase induction, and superior UV photoprotection (CPD −38–44% vs −22–28%) in matched concentration experiments. PT-141, with MC1R Ki ~3.5 nM, provides a partial MC1R agonist profile and the cleanest available MC4R-dominant research pharmacology when MC4R-specific biology is the endpoint. The MT-II/PT-141 pharmacological pair, combined with BMS-470539 (MC1R block) and HS024 (MC4R block), forms the complete mechanistic control set for attributing observed biology unambiguously to MC1R, MC4R, MC3R, or MC5R in melanocyte and skin pigmentation research contexts.
- William is a research analyst at Peptides Lab UK, specialising in research peptides, laboratory compounds, and sourcing standards for high-purity peptide products.