Melanocortin System Peptides
MT1, MT2, PT141 — Research Peptides Targeting MC Receptors
Synthetic melanocortin peptide analogues for studying MC1R–MC5R receptor pharmacology, pigmentation biology, and appetite/sexual behavior pathways. For research use only.
Browse Catalog Contact SalesMelanocortin Peptide Analogues
MT1 (Afamelanotide)
Ac-Ser-Tyr-Ser-(Nle)-Glu-His-(d-Phe)-Arg-Trp-Gly-Lys-Pro-Val-NH2
Linear α-MSH analogue with enhanced MC1R selectivity. FDA-approved (as Scenesse®) for erythropoietic protoporphyria. Research applications in melanogenesis and photoprotection.
MT2 (Melanotan II)
Ac-(Nle)-Asp-His-(d-Phe)-Arg-Trp-Lys-NH2, cyclic (2→7)-lactam
Non-selective cyclic melanocortin agonist. Activates MC1R through MC5R. Widely studied for pigmentation, appetite, and sexual behavior in preclinical models.
PT141 (Bremelanotide)
Ac-(Nle)-Asp-His-(d-Phe)-Arg-Trp-Lys, cyclic (2→7)-lactam
MC4R-preferring cyclic peptide. Active metabolite of MT2. FDA-approved (as Vyleesi®) for hypoactive sexual desire disorder. Research tool for studying central melanocortin pathways.
Receptor Selectivity Comparison
Relative binding affinity at melanocortin receptor subtypes (+ low → ++++ high)
| Peptide | Structure | MC1R | MC3R | MC4R | MC5R | Key Research Area |
|---|---|---|---|---|---|---|
| α-MSH (reference) | Linear, 13 AA | +++ | ++ | +++ | ++ | Endogenous ligand |
| MT1 (Afamelanotide) | Linear, 13 AA (modified) | ++++ | + | ++ | + | Pigmentation |
| MT2 (Melanotan II) | Cyclic, 7 AA (lactam) | +++ | +++ | +++ | +++ | Non-selective |
| PT141 (Bremelanotide) | Cyclic, 7 AA (lactam) | ++ | ++ | ++++ | + | Sexual behavior |
The Melanocortin Receptor Family
MC1R
Expressed in melanocytes. Primary mediator of eumelanin synthesis and UV-protective pigmentation response.
MC3R / MC4R
Central nervous system receptors. MC4R is the primary target for appetite regulation and sexual behavior pathways (PT141 target).
MC5R
Expressed in sebaceous glands and other tissues. Implicated in exocrine gland function and immune regulation.
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