Comparison · Melanocortin analog

Melanotan-1 vs PT-141

These compounds share a catalog class. That grouping makes their declared properties useful to compare, but does not establish experimental or clinical interchangeability.

For in vitro and laboratory research only. Not for human or veterinary use, diagnosis or treatment. These research materials have not been evaluated by COFEPRIS.

What distinguishes these compounds

Melanotan-1 and PT-141 belong to the melanocortin class but have different structures. PT-141 is a cyclic heptapeptide derived structurally from Melanotan-2, with a terminal carboxylic acid in place of an amide; Melanotan-1 is described by its alpha-MSH substitutions.

The entries emphasize different receptor contexts: MC1R in the Melanotan-1 mechanism and MC4R, with reported MC3R involvement, in the PT-141 research description. These summaries do not establish interchangeable effects or a ranking of the materials.

What they are

Melanotan-1: Melanotan-1 is a synthetic analog of alpha-melanocyte-stimulating hormone, with norleucine and D-phenylalanine substitutions described in the literature as determinants of its stability. NDP-alpha-MSH has been studied in in vitro melanocortin receptor binding assays and as a reference for comparing structural variants across subtypes. It has been studied in models of melanogenesis in in vitro studies.

PT-141: PT-141 is a cyclic heptapeptide analog of alpha-MSH, structurally derived from Melanotan-2 by replacing the terminal amide group with a carboxylic acid. In research literature, it binds to melanocortin receptors with a reported preference for MC4R and MC3R. It has been studied in models of central melanocortin signaling in rodent studies.

Mechanisms described in the literature

Melanotan-1: MC1R is a Gs protein-coupled receptor present in melanocytes. Its activation modulates the cyclic AMP pathway and tyrosinase expression in cellular models.

PT-141: MC4R is a Gs protein-coupled receptor expressed in hypothalamic nuclei. Its activation modulates cyclic AMP production in cellular models.

Declared chemical identity, field by field

A dash means that the catalog does not declare that field for the compound. If neither entry declares a field, the row is omitted. A label purity specification of ≥ 99 % is not an analytical result; results must come from the certificate for the relevant batch.

Melanotan-1 vs PT-141: declared technical information
Field	Melanotan-1	PT-141
Chemical name	[Nle4, D-Phe7]-alpha-MSH	Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH
Sequence	Ac-Ser-Tyr-Ser-Nle-Glu-His-D-Phe-Arg-Trp-Gly-Lys-Pro-Val-NH2	Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH
Molecular formula	C78H111N21O19	C50H68N14O10
Molecular weight	1646.9 Da	1025.16 Da
CAS number	75921-69-6	189691-06-3
Form	Lyophilized powder	Lyophilized powder
Appearance	White to off-white solid	White to off-white solid
Solubility	Soluble in sterile water and bacteriostatic water	Soluble in sterile water and bacteriostatic water
Storage	−20 °C, protected from light	−20 °C, protected from light
Stability after reconstitution	Keep refrigerated at 2–8 °C and use within the period defined by the laboratory protocol	Keep refrigerated at 2–8 °C and use within the period defined by the laboratory protocol

Laboratory handling: Melanotan-1

Reconstitution: Laboratory procedure: allow the closed vial to reach room temperature, disinfect the septum and slowly transfer the diluent against the inner wall of the vial. Do not shake; gently swirl the vial until fully dissolved. Record the volume, diluent and date in the batch log.

Storage: Sealed vial of lyophilized material: store at −20 °C, protected from light and moisture. Avoid repeated freeze-thaw cycles of reconstituted material; aliquot when the experimental design permits.

Protective equipment: Handle in a clean work area with a lab coat, nitrile gloves and eye protection. Dispose of vials, tips and sharps according to the laboratory waste procedure.

Laboratory handling: PT-141

Protective equipment: Handle in a clean work area with a lab coat, nitrile gloves and eye protection. Dispose of vials, tips and sharps according to the laboratory waste procedure.

Catalog presentations

Consult each product page for its current presentations, availability, batch documentation and price. This comparison does not freeze commercial information in the research text.

Complete research references

The compendium entries contain the extended definitions, research context and indexed bibliography for each compound. The comparison organizes declared information; it does not replace study-specific interpretation or batch identity evidence.