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What Is Melanotan II?

Research overview · Published July 2026 · For research use only

Melanotan II is a synthetic cyclic heptapeptide analog of α-melanocyte-stimulating hormone (α-MSH) studied in preclinical melanocortin-receptor research. It is not an FDA-approved drug.

The short answer

Melanotan II is a cyclic, non-selective agonist of the melanocortin receptors, modeled on α-MSH. In the research literature it is studied for melanocortin-receptor signaling and melanogenesis (the pigment-producing pathway). It is a research compound and is not approved for human use.

Composition and specifications

CompoundMelanotan II
ClassCyclic α-MSH analog; melanocortin-receptor agonist
Also known asMT-II · CAS 121062-08-6
Sequence / lengthCyclic heptapeptide (α-MSH analog)
CAS number121062-08-6
Molecular weight1024.2 g/mol
Purity (typical)≥99.0%
AppearanceWhite lyophilized powder; water-soluble

Values above reflect the compound's published specification. As with any research material, the definitive confirmation of identity and purity for a given lot is the mass-spectrometry and HPLC data on its Certificate of Analysis.

How it is described mechanistically

Melanotan II is characterized as a non-selective agonist at melanocortin receptors (including MC1R and MC4R). MC1R activation is associated with melanogenesis in research models, while MC4R activity is studied in other melanocortin-signaling contexts. These are mechanistic descriptions from laboratory research.

What has research examined?

Published Melanotan II work is preclinical. Areas examined include:

These describe research directions and receptor-level pharmacology, not endorsed human uses.

Research use only. Melanotan II is intended for laboratory and experimental use by qualified researchers — not for human or veterinary administration, diagnosis, or treatment. Nothing on this page is medical advice.

How is it characterized and tested?

Two questions matter most about any peptide sample in a research context: is it the right molecule, and how pure is it. Those are answered by analytical testing — commonly mass spectrometry for identity and HPLC for purity — with both reported on a batch-specific Certificate of Analysis (COA). An independent, published COA lets a researcher confirm identity and purity before beginning work. See peptide handling and storage for how samples are kept stable once received.

Primary literature: browse peer-reviewed studies on Melanotan II at PubMed.

Common questions

Is Melanotan II approved for human use?

No. Melanotan II is not an FDA-approved drug. Research-grade material is for laboratory research use only and is not intended for human administration.

What is Melanotan II studied for?

Melanocortin-receptor signaling and melanogenesis (the pigmentation pathway) in preclinical models. This page describes receptor-level pharmacology, not any human use.

How does Melanotan II relate to α-MSH?

It is a synthetic cyclic analog of α-MSH designed to be more stable and to act on the same melanocortin-receptor family.