Source comparison
Melanotan 2 vs Melanotan 1: Structural and Functional Comparison
Melanotan 1 (afamelanotide, marketed as Scenesse for erythropoietic protoporphyria) and Melanotan 2 share the same core melanocortin pharmacophore. The His-Phe-Arg-Trp tetrapeptide sequence required for receptor binding. But differ critically in their stereoch
This comparison does not assign a generated winner or score.
- Melanotan 1 (afamelanotide, marketed as Scenesse for erythropoietic protoporphyria) and Melanotan 2 share the same core melanocortin pharmacophore. The His-Phe-Arg-Trp tetrapeptide sequence required for receptor binding. But differ critically in their stereochemistry and cyclization patterns. Melanotan 1 is a linear 13-amino-acid peptide with norleucine substitutions and acetylation at the N-terminus, designed to resist enzymatic degradation while maintaining MC1R selectivity. Its extended structure produces a half-life of approximately 33 minutes, requiring continuous infusion or frequent dosing to maintain therapeutic plasma levels.
- Melanotan 2, by contrast, incorporates the D-phenylalanine substitution and a shorter lactam bridge, creating a more rigid cyclic structure with a half-life exceeding 24 hours. This modification shifts receptor binding from MC1R-selective to non-selective across MC1R, MC3R, MC4R, and MC5R. The functional consequence: Melanotan 1 produces melanogenesis with minimal appetite suppression, erectile effects, or nausea, while Melanotan 2 produces all four effects simultaneously due to MC4R and other receptor activation.
- The table below distills the structural and pharmacological distinctions that define each peptide's research and clinical profile.
- Amino Acid Length
- 13 residues (linear)
- 7 residues (cyclic)
- MT2's shorter sequence and cyclic structure improve proteolytic stability
- Key Structural Modification
- Norleucine substitutions, N-terminal acetylation
- D-Phe substitution, lactam bridge (Asp-Lys)
- D-Phe inversion in MT2 extends half-life and broadens receptor binding
- Receptor Selectivity
- MC1R-selective
- Non-selective (MC1R, MC3R, MC4R, MC5R)
- MT1's selectivity limits effects to melanogenesis; MT2 activates appetite and erectile pathways
- Half-Life
- ~33 minutes
- ~33 hours
- MT2 requires less frequent dosing but has prolonged systemic exposure
- FDA Approval Status
- Approved (Scenesse, 2019, for EPP)
- Not approved; research compound only
- MT1 has regulatory clearance for rare disease indication; MT2 does not
- Primary Effects
- Melanogenesis, photoprotection
- Melanogenesis, appetite suppression, erectile function, nausea
- MT2's MC4R activity introduces metabolic and sexual function effects absent in MT1
- Melanotan 1's FDA approval for erythropoietic protoporphyria (EPP). A rare disorder causing severe photosensitivity. Validates the MC1R-selective melanogenesis pathway as therapeutically viable, but the approval is restricted to subcutaneous implant formulations (Scenesse) that deliver controlled, sustained release over 60 days. Melanotan 2 has not undergone Phase III trials for any indication and remains available exclusively as a research peptide through suppliers like Real Peptides, where every batch undergoes amino-acid sequencing and purity verification to ensure consistency for laboratory use.