Melanocortin
Melanotan II
Also listed as MT-II, Melanotan-II
Cyclic α-MSH analogue (melanocortin receptor agonist)
- MC1R
- MC3R
- MC4R
- MC5R
- Formula
- C50H69N15O9
- Molar mass
- 1024.18 g/mol
- CAS number
- 121062-08-6
Identity
What the molecule is, from its PubChem record. These are the figures a certificate of analysis should agree with.
- Class
- Cyclic α-MSH analogue (melanocortin receptor agonist)
- Sequence
Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH₂
- Seven residues with an N-terminal acetyl cap and a C-terminal amide.
- Nle is norleucine; D-Phe is D-phenylalanine.
- The ring is a lactam bridge between the side chains of aspartate and lysine.
- Molecular formula
- C50H69N15O9
- Molar mass
- 1024.18 g/mol
- CAS number
- 121062-08-6
- PubChem
- CID 92432
Checked against PubChem on 27 September 2026. Molar mass is calculated from the formula with standard atomic weights and agrees with PubChem’s published molecular weight. In sequences, H- marks a free N-terminus, -OH a free C-terminal acid and -NH₂ a C-terminal amide.
Research context
Melanotan II is a cyclic lactam analogue of α-melanocyte-stimulating hormone (α-MSH), closed by a bridge between aspartate and lysine side chains. It is a non-selective melanocortin receptor agonist, used in receptor-expressing cell lines as a reference ligand for binding and cAMP signalling at MC1R, MC3R, MC4R and MC5R.
Research use only. Everything on Vialwise concerns research-grade material sold for laboratory and analytical use only. It is not a registered medicine, is not supplied for human or veterinary use, and nothing here is medical advice.
Storage and handling
Store sealed lyophilised powder at −20 °C, dry and away from light.
Let the vial reach room temperature before opening, so moisture doesn’t condense on the powder.
Reconstitute in sterile water, or in the buffer your protocol specifies. Swirl gently rather than shake.
Contains tryptophan, which is light-sensitive. Use amber tubes or wrap them in foil.
Split the solution into single-use aliquots and keep them frozen, so no portion goes through repeated freeze–thaw.
General laboratory practice for this class of material; your institution’s own procedures come first. To work out concentration and aliquot volumes from a vial’s mass, use the reconstitution calculator. For the reasoning behind each step, read storing lyophilised peptides.
Published lab reports
Lab reports for Melanotan II at Au Peptide Labs Our store
The one supplier whose full report list we have.
Open each lab-linked report on the lab’s own website to confirm it.
- Lab link
Melanotan 2
Task #149241Added 31 July 2026
Verify at janoshik.com99.942%purity
Other suppliers publish their reports on their own sites. Where each supplier publishes its COAs
Vialwise is published by APL Research Pty Ltd, which also runs Au Peptide Labs. Every supplier, ours included, is scored on the same published checklist. How we handle this
Any supplier
Check any supplier’s Melanotan II COA
These checks take a few minutes and work the same on a report from any supplier, ours included. The walkthrough shows each one on a real Janoshik report.
How to verify a Janoshik COAOpen it at the lab
The report should load on the testing lab’s own website from the verify link or task number, not only as a PDF or screenshot from the supplier.
Match the name
The sample should be named Melanotan II, MT-II or Melanotan-II, or a clear equivalent. A different compound name means a different report.
Match the mass
If the report includes a mass-spectrometry result: a deconvoluted average-mass result should sit close to 1024.18 g/mol; high-resolution reports give the slightly lower monoisotopic mass, and raw spectra show m/z for charged ions (mass ÷ charge). How HPLC and mass spec work.
Match the vial
The sample amount on the report should match the vial size you’re buying. A report on a different size or an older batch tells you less about the vial in front of you.
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