Peptides
Melanotan II
10mg
Cyclic lactam heptapeptide. α-MSH synthetic analogue.
>99% purity · Third-party tested · Batch UKPL-331 · View certificate
- Same-day dispatch before 3pm, Mon to Fri
- Add £44.01 more for free UK delivery
- Cold-chain shipping. Always. Dry-cold pack, Royal Mail Tracked 24
- Lost, damaged or wrong? Replaced free if you tell us within 48 hours.
- Research use only. For in-vitro laboratory research. Not for use in humans or animals, or in food, drugs or diagnostics. Not evaluated by the MHRA or FDA. The buyer is responsible for handling and regulatory compliance.
Bulk Pricing
Counted across your basket, any mix of products.
| Vials in basket | Discount | Per vial |
|---|---|---|
| 1 | None | £24.99 |
| 3-4 | 5% | £23.74 |
| 5-9 | 8% | £22.99 |
| 10-50 | 12% | £21.99 |
Bacteriostatic Water 10ml
Required to reconstitute lyophilised peptides.
What is Melanotan II?
Melanotan II (MT-II, also sold as Melanotan 2, MT-2 or MT2) is a synthetic cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone. Receptor pharmacology labs use it as a reference ligand at melanocortin receptors. Each Melanotan II 10mg vial holds a white lyophilised powder.
Full description
Its sequence is Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH₂, with formula C₅₀H₆₉N₁₅O₉, molecular weight 1024.2 g/mol and CAS number 121062-08-6. Al-Obeidi, Castrucci, Hadley and Hruby reported it in the Journal of Medicinal Chemistry in 1989, with molecular dynamics guiding the design.
It makes three changes to the alpha-MSH 4-10 fragment. Norleucine replaces methionine at position 4 and D-phenylalanine sits at position 7. A lactam bridge between Asp5 and Lys10 closes a 23-membered ring.
Melanotan II Research Applications
- Potency: in the 1989 lizard skin bioassay, MT-II was about 90 times as potent as alpha-MSH, with prolonged activity (Al-Obeidi et al., J Med Chem, 1989).
- Receptor binding: it binds human MC1, MC3, MC4 and MC5 receptors expressed in cell lines (Schiöth et al., Peptides, 1997).
- Selectivity by design: on the same scaffold, D-Nal(2') at position 7 gives SHU-9119, which favours MC4R (Schiöth et al., 1997).
Study details
In receptor assays MT-II is the non-selective reference agonist that candidate subtype-selective ligands are compared against. It is also the parent scaffold for structure-activity work on positions 5 to 10. Its first potency data came from frog and lizard skin bioassays, before the human receptors were cloned.
Melanotan II vs Melanotan I vs SHU-9119
Melanotan I (afamelanotide) is Ac-[Nle4, D-Phe7]-alpha-MSH: linear, 13 residues, 1646.8 g/mol. Melanotan II keeps the Nle4 and D-Phe7 changes but uses only the 4-10 fragment, closed into a ring by a lactam bridge. SHU-9119 is the Melanotan II scaffold with D-Nal(2') at position 7, a change that shifts binding towards MC4R. Each is a separate compound with its own CAS number.
Research Overview
The 1989 design started from two superpotent alpha-MSH analogues: linear Ac-[Nle4, D-Phe7]-alpha-MSH and a cyclic disulphide, Ac-[Cys4, Cys10]-alpha-MSH. Al-Obeidi and colleagues made seven cyclic lactam analogues and tested them in frog (Rana pipiens) and lizard (Anolis carolinensis) skin bioassays. Ring size decided potency. Analogues with 23-membered rings were about 100 times as potent as alpha-MSH in lizard skin, and larger or smaller rings lost potency. Only the 23- and 24-membered rings gave prolonged activity.
Schiöth and colleagues (Peptides, 1997) later measured binding at human MC1, MC3, MC4 and MC5 receptors expressed in cells. The two cyclic lactams, MT-II and SHU-9119, bound with higher affinity overall than the cyclic disulphide analogues. Swapping D-Phe7 for D-Nal(2')7 moved selectivity towards MC4R in both ring types.
There are five melanocortin receptors. MC1R is the melanocyte-stimulating hormone receptor and MC2R the adrenocorticotropin receptor. MC3R and MC4R are expressed mainly in the central nervous system. A 2022 review in Biomolecules covers ligands for these two neural receptors, including the approved drugs setmelanotide and bremelanotide.
Product Specifications
- Molecular Formula
- C₅₀H₆₉N₁₅O₉
- Molecular Weight
- 1024.2 g/mol
- CAS Number
- 121062-08-6
- Sequence
- Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH₂
- Peptide Class
- Cyclic lactam alpha-MSH (4-10) analogue
- Purity
- >99% (RP-HPLC)
- Batch
- UKPL-331
- Storage
- -20°C lyophilised, 2-8°C reconstituted, protect from light
- Appearance
- White lyophilised powder
- Form
- Lyophilised powder
Certificate of Analysis
Third-party tested
- Batch
- UKPL-331
- Purity
- >99%
- Method
- RP-HPLC
- Lab
- Marfleet Analytical Services
- Tested
- Aug 2026
Need the certificate for an earlier batch? Request an older CoA
Storage and Reconstitution
Store sealed vials at -20°C, in the dark and away from moisture, for up to 24 months. After reconstitution, keep the solution at 2-8°C in an amber or foil-wrapped vial and use it within 4 weeks. For longer storage, freeze single-use aliquots at -20°C and avoid repeated freeze-thaw cycles.
Vials are sold on their own, without bacteriostatic water for mixing or other supplies.
How to reconstitute and handle
Let the vial reach room temperature and swab both stoppers with alcohol. Add the bacteriostatic water slowly down the inside wall of the vial, away from direct sunlight and strong lighting. Swirl gently until the powder dissolves, without shaking. The solution should be clear and colourless.
- Use amber or foil-wrapped vials for the stock and every aliquot. Tryptophan at position 9 is the light-sensitive residue.
- The single tryptophan absorbs at 280 nm, so UV absorbance can confirm the concentration of a stock solution.
For the full method, see the peptide reconstitution guide and the reconstitution calculator.
Research References
- Potent and prolonged acting cyclic lactam analogues of alpha-melanotropin, design based on molecular dynamics (J Med Chem, 1989)
- Selectivity of cyclic D-Nal7 and D-Phe7 substituted MSH analogues for the melanocortin receptor subtypes (Peptides, 1997)
- Ligands for Melanocortin Receptors, Beyond Melanocyte-Stimulating Hormones and Adrenocorticotropin (Biomolecules, 2022)
Published research on Melanotan II is indexed on PubMed. See our full UK buyer's guide for Melanotan II.
Melanotan II Price (UK)
Melanotan II 10mg is for sale at £24.99 per vial, supplied from stock in the UK with a published third-party HPLC certificate. UK delivery is £4.50 by Royal Mail Tracked 24, free over £69.
| Vial | Price | Cost per mg | Availability |
|---|---|---|---|
| Melanotan II 10mgThis page | £24.99 | £2.50 | In stock |
Prices are in GBP per vial and match the basket. See the FAQ for delivery and payment options, and quality & testing for how each batch is checked.
Frequently Asked Questions
What is Melanotan 2 (MT2)?
Melanotan 2 is a synthetic cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone, built on the alpha-MSH 4-10 fragment. Al-Obeidi and colleagues first reported it in the Journal of Medicinal Chemistry in 1989. We supply it as a lyophilised powder for in-vitro research only.
How does Melanotan 2 work at the receptor level?
It binds melanocortin receptors, the receptors for alpha-MSH. The Asp5-Lys10 lactam bridge encloses the His-Phe-Arg-Trp core in a ring, with D-Phe at position 7. These are receptor and bioassay data, not evidence of any effect in humans.
Is MT2 selective for a single melanocortin receptor?
No. MT2 binds human MC1, MC3, MC4 and MC5 receptors (Schiöth et al., Peptides, 1997), so assays use it as a non-selective reference agonist. Work that needs one subtype uses derivatives. Replacing D-Phe7 with D-Nal(2')7, as in SHU-9119, shifts binding towards MC4R.
What is the difference between Melanotan 1 and Melanotan II?
Melanotan I (afamelanotide) is a linear 13-residue analogue of the full alpha-MSH sequence, with Nle4 and D-Phe7. Melanotan II is a cyclic lactam built on the shorter 4-10 fragment. They differ in formula, molecular weight and CAS number, so a protocol cannot swap one for the other.
What is the molecular formula and CAS number of the Melanotan 2 peptide?
The melanotan 2 peptide is C₅₀H₆₉N₁₅O₉, with a molecular weight of 1024.2 g/mol and CAS number 121062-08-6. Its full notation is Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH₂, also written Ac-Nle4-cyclo[Asp5-His6-D-Phe7-Arg8-Trp9-Lys10]-alpha-MSH(4-10)-NH₂.
Is Melanotan II approved or licensed for human use in the UK?
No. Melanotan II has no marketing authorisation from the MHRA or any other medicines regulator. It is not approved for human or veterinary use anywhere. We supply it only as a reference material for in-vitro laboratory research.
Why must Melanotan II be stored protected from light?
Its tryptophan at position 9 oxidises in light, and the oxidised peptide shows up as extra RP-HPLC peaks. That lowers the amount of intact peptide in an assay. Keep vials in the dark and reconstitute away from direct sunlight.
Is Melanotan II legal to buy in the UK, and is it a licensed medicine?
It can be bought in the UK as a reference material for in-vitro laboratory research. It is not a licensed medicine in the UK or anywhere else. Buyers must be 18 or over and confirm research-only use at checkout.
Where can I buy Melanotan II 10mg in the UK for research?
You can buy Melanotan II 10mg online from our UK stock, with a third-party certificate for each batch. Orders placed before 3pm on a working day are dispatched the same day, and UK delivery is free over £69.
What purity is your Melanotan 2 (MT2) and how is it verified?
The current batch measured above 99% by RP-HPLC at an independent laboratory. The certificate section gives the batch number, lab and test date, with the full report. After long storage, oxidised tryptophan is the impurity to look for on a repeat chromatogram.
What is MT2 peptide used for in research?
MT2 peptide is a reference agonist in melanocortin receptor binding assays and a parent scaffold for structure-activity studies. SHU-9119, for example, differs from it at position 7 only. It is sold for in-vitro research, not for human or cosmetic use.
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