Comparison · Melanocortin analog

Melanotan-2 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

PT-141 is structurally derived from Melanotan-2 by replacing the terminal amide group with a carboxylic acid. Both are cyclic heptapeptide analogues, but the terminal group is a chemical distinction that should remain visible in an identity comparison.

Melanotan-2 is described as having a nonselective melanocortin profile including MC1R, MC3R and MC4R. PT-141's entry reports a preference for MC4R and MC3R. Relative preference is not the same as absolute receptor exclusivity or equivalent biological response.

What they are

Melanotan-2: Melanotan-2 is a cyclic heptapeptide analog of alpha-melanocyte-stimulating hormone, cyclized through a lactam bridge. In preclinical models, it binds to several melanocortin receptors, including MC1R, MC3R and MC4R, with a nonselective profile. It has been investigated in models of melanocortin signaling in rodent 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-2: Cyclization restricts the peptide's conformation and modifies its relative affinity for receptor subtypes. All of these are Gs protein-coupled receptors 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-2 vs PT-141: declared technical information
Field	Melanotan-2	PT-141
Chemical name	Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2	Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH
Sequence	Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2	Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH
Molecular formula	C50H69N15O9	C50H68N14O10
Molecular weight	1024.2 Da	1025.16 Da
CAS number	121062-08-6	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-2

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.