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Catalog/Melanotan II

Melanotan II

Also known as MT-2 · MT-II

Synthetic cyclic analog of α-MSH; non-selective melanocortin receptor agonist.

Overview

Melanotan II is a cyclic heptapeptide α-MSH analog developed at the University of Arizona. Acts as a non-selective agonist across MC1R, MC3R, MC4R, and MC5R — pigmentation and sexual-response effects have both been documented.

Background

Melanotan II is a synthetic cyclic analog of α-melanocyte-stimulating hormone (α-MSH), developed at the University of Arizona. It is a non-selective agonist across the melanocortin receptors MC1R through MC5R.

Through MC1R it stimulates melanin production (pigmentation); through MC4R it influences central sexual-response pathways. Both effects are documented in research, but its non-selectivity also drives side effects, and it is not FDA-approved.

Mechanism

Non-selective melanocortin receptor (MC1-5R) agonism.

Key research findings

  • Pigmentation — MC1R agonism stimulates eumelanin production via Gs-coupled cAMP signaling.
  • Central sexual response — MC4R activation drives arousal effects; the same MC4R activity also produces the nausea, flushing, and spontaneous erections documented in human studies.
  • Compared to Melanotan I (afamelanotide) — MT-II is a truncated, non-selective MC1–5R agonist, whereas afamelanotide is highly MC1R-selective and FDA-approved (Scenesse) for photoprotection in erythropoietic protoporphyria.
  • Relationship to PT-141 — PT-141 (bremelanotide) is a metabolite refined toward MC4R / sexual response and away from pigmentation.
  • Not FDA-approved — its non-selectivity drives off-target effects; research compound.

How Melanotan II is made

Behind every vial of Melanotan II is the same exacting pipeline every research peptide runs — but the chemistry plays out differently for this molecule. Here is how Melanotan II, specifically, is brought into being.

  1. On paper first

    On paper, Melanotan II is C50H69N15O9 — about 1,024.2 daltons of precisely arranged atoms. Before a single bond is made, the target sequence, salt form, and purity threshold are written down as the contract the finished material must meet.

  2. Built residue by residue

    Melanotan II is assembled by solid-phase peptide synthesis — the chain grows one protected residue at a time on resin, and what you fail to build cleanly here you pay to remove later. It also carries cyclization, an extra step beyond a plain chain that adds both capability and cost.

  3. Purity is won here

    The crude mixture — Melanotan II plus its deletions and side products — is then separated on preparative HPLC, and where the cut is taken decides the difference between a genuinely pure peptide and a barely-passable one.

  4. Proven, then protected

    A real batch of Melanotan II proves itself: identity confirmed by mass spectrometry against its ~1,024.2 Da, purity read directly off an analytical HPLC trace, water and counterion content measured. That batch-specific certificate of analysis is the only honest way to know what is actually in a vial of Melanotan II — and a short, cold, accountable chain of custody is how that purity survives the trip to your bench.

Walk the full synthesis pipeline

Handling, storage & why purity is hard

Producing Melanotan II to a genuine purity spec means solid-phase synthesis, preparative HPLC purification, and batch quality control — none of it cheap, and none of it something you can verify by eye.

Don't judge a vial by its cake. A fluffy, good-looking lyophilized powder reflects bulking agents and freeze-drying parameters — not purity. Insist on a batch-specific certificate of analysis.

How peptides are made — the full pipeline

Research areas

  • Pigmentation biology
  • Sexual dysfunction
  • Photoprotection

Research-area guides

Latest research

Recent clinical trials and publications mentioning Melanotan II, pulled automatically from ClinicalTrials.gov and PubMed and refreshed daily. Listings are unfiltered search results, not curated endorsements.

Frequently asked questions

What is Melanotan II?+

Melanotan II is a synthetic, non-selective melanocortin-receptor agonist (an α-MSH analog) studied for pigmentation and sexual-response effects.

How is it related to PT-141?+

PT-141 (bremelanotide) is a melanocortin agonist with preferential MC4R activity studied for sexual function; Melanotan II is non-selective and also drives pigmentation.

Is it approved?+

No — Melanotan II is not FDA-approved. This page is a research and educational reference, not a usage recommendation.

What receptors does it act on?+

It activates melanocortin receptors MC1R through MC5R without selectivity.

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Dosing protocols, mechanism, comparisons, and the latest trials — citation-backed answers grounded in PubMed, PubChem, and ClinicalTrials.gov.