What Melanotan-2 is
Melanotan-2 — commonly written MT2 or MT-II — is a synthetic cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone (α-MSH). Where native α-MSH is linear and degrades quickly, Melanotan-2 is cyclised through a lactam bridge, which constrains the molecule into a shape that resists enzymatic breakdown and holds the receptor-binding residues in position. That single structural decision is why it appears so often in the literature: it is a stable, non-selective probe for a receptor family that is otherwise difficult to study.
- Melanotan-2Cyclic α-MSH analogue
- MC1R, MC3R, MC4RNon-selective across melanocortin receptors
- Gs → cAMP → MITFMelanogenesis via MC1R; MC4R drives the off-target effects
- Pigmentation modelsPreclinical
Mechanism as described in published research. Nothing here describes an effect in a person — these compounds are supplied for laboratory research use only.
Melanocortin receptor signalling
The melanocortin system comprises five G-protein-coupled receptors, MC1R through MC5R, each associated with a different area of physiology — pigmentation at MC1R, steroidogenesis at MC2R, energy balance and feeding at MC3R and MC4R, and exocrine function at MC5R. Melanotan-2 is a non-selective agonist across most of this family, which is precisely what makes it useful and what complicates interpretation.
In research terms, a non-selective agonist is a blunt instrument that reaches every arm of the pathway at once. Study designs therefore tend to pair it with selective antagonists, or with a receptor-specific comparator, to attribute an observed effect to a particular receptor rather than to melanocortin signalling in general. Where a protocol is specifically interested in MC3R/MC4R rather than pigmentation, PT-141 (bremelanotide) — a metabolite-derived analogue lacking the pigmentation-associated activity — is the more common tool.
What the literature covers
Published work using Melanotan-2 clusters into a few areas:
- Pigmentation models — MC1R activation and the eumelanin synthesis pathway in melanocyte culture and animal models.
- Energy balance and feeding behaviour — MC3R/MC4R signalling in hypothalamic research, where the melanocortin system is a well-established regulator.
- Receptor pharmacology — as a reference agonist for characterising binding affinity and downstream cAMP response across receptor subtypes.
- Structure–activity work — the cyclised scaffold is a starting point for analogues designed to be selective where Melanotan-2 is not.
For comparison, Kisspeptin-10 acts on an entirely separate upstream axis and is often examined alongside melanocortin work in reproductive endocrinology.
Identity and verification
Melanotan-2 has the molecular formula C50H69N15O9 and a molecular weight of 1024.2 g/mol (CAS 121062-08-6). Identifiers matter more here than in most categories: research compounds are sold under trade names, development codes and abbreviations that do not always refer to the same molecule, and a formula is unambiguous where a name is not.
The lot we currently hold measured 99.83% for the 10 mg (lot 261807), tested by Freedom Diagnostics. The certificate is published in full, including the raw chromatogram and mass spectrum — so the number can be read off the underlying trace rather than taken on trust.
We use two laboratories because purity and identity are different questions. Vanguard Laboratory is ISO/IEC 17025:2017 accredited (A2LA #6377.01.01) and reports chromatographic purity and net quantity with a stated measurement uncertainty. Freedom Diagnostics reports HPLC-UV purity together with LC-MS identity confirmation — the test that catches a substituted compound rather than merely an impure one. A sample can be 99% pure and still be the wrong molecule. How we test →
Handling, reconstitution and storage
Melanotan-2 ships lyophilized — freeze-dried to a solid and sealed under vacuum — which is what makes it stable in transit rather than a solution racing a clock. Reconstitute with bacteriostatic water, added slowly down the inside wall of the vial rather than directly onto the powder, then swirled gently. Do not shake: mechanical shear is one of the few things that reliably degrades a peptide in the lab.
Final concentration is a function of the volume added, not of the compound, so the same vial can be prepared at very different concentrations. The reconstitution calculator works out the volume for a target concentration and the reconstitution guide covers the procedure. Store lyophilized vials at −20 °C (−4 °F) protected from light; refrigerate once in solution, and see the storage and stability guide for how long reconstituted material holds.
Common questions
Is MT2 the same as Melanotan-2?
Yes. MT2, MT-2 and MT-II all refer to Melanotan-2, a synthetic cyclic analogue of alpha-melanocyte-stimulating hormone. The abbreviations are used interchangeably in vendor listings and literature.
What is the difference between Melanotan-2 and PT-141?
PT-141 (bremelanotide) is derived from a Melanotan-2 metabolite and lacks the pigmentation-associated activity. Melanotan-2 is a non-selective agonist across most melanocortin receptors; PT-141 is studied where the pigmentation arm is a confounder rather than the subject.
Why is Melanotan-2 cyclic?
The lactam bridge constrains the peptide into a fixed conformation, which both resists enzymatic degradation and holds the receptor-binding residues in position. Native alpha-MSH is linear and breaks down far faster, which makes it impractical as a research probe.
How is Melanotan-2 reconstituted and stored?
It ships lyophilized and is reconstituted with bacteriostatic water added slowly down the vial wall, then swirled rather than shaken. Store lyophilized vials at −20 °C (−4 °F) protected from light, and refrigerate once in solution.
Where to get it
Buy research-grade Melanotan-2 — independently tested, certificate published, shipped from Miami with cold-chain packaging. Current pricing for every size is on the price list, and we ship worldwide.
Research use only
Everything referenced here is supplied strictly for laboratory research. These compounds are not drugs, foods, cosmetics or medical devices, are not for human or veterinary use, and are not approved for diagnostic or therapeutic application. Mechanisms are described as studied in preclinical and laboratory research; nothing above describes dosing, treatment or clinical outcome.
