Source comparison
PT-141 vs Melanotan II: Key Research Differences
Researchers frequently need to choose between PT-141 and Melanotan II (MT-II) as tool compounds for melanocortin system experiments. These compounds are structurally related but pharmacologically distinct in ways that matter for experimental design. The core d
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- Researchers frequently need to choose between PT-141 and Melanotan II (MT-II) as tool compounds for melanocortin system experiments. These compounds are structurally related but pharmacologically distinct in ways that matter for experimental design.
- The core difference: MT-II is a broad melanocortin receptor agonist with significant activity at MC1R, MC3R, and MC4R. PT-141 shows reduced MC1R activity while maintaining high affinity at MC3R and MC4R. This relative selectivity makes PT-141 more appropriate when researchers want to probe MC3R or MC4R-mediated biology without simultaneously activating MC1R-dependent pigmentation pathways.
- Structural difference summary:
- C-terminus
- Free carboxyl (-OH)
- Amide (-NH2)
- MC1R activity
- Lower
- Higher
- MC3R activity
- High
- MC4R activity
- CAS number
- 121062-08-6
- When to use MT-II instead: For experiments requiring broad melanocortin receptor activation or where MC1R engagement is the research question, MT-II is the more appropriate tool. For MC4R-specific CNS receptor research in vitro, PT-141 provides a cleaner pharmacological signal.
- The two compounds also work well as a paired comparison set. Running both at equipotent MC4R concentrations allows researchers to assess the contribution of MC1R to any observed cellular response.
- Shop Melanotan II Research Peptide at Palmetto Peptides
- For a detailed side-by-side comparison including receptor potency data and experimental design guidance, see: PT-141 vs Melanotan II: Comparative Analysis for Research Peptide Applications