Melanotan II MT2 · MT-II
Melanotan II (MT2, MT-II) is a cyclic lactam analogue of alpha-MSH(4-10) that binds the MC1, MC3, MC4 and MC5 melanocortin receptors. Clean Peptide supplies it as a 10 mg lyophilised vial with a per-lot ILS Laboratories certificate.
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Verified test results
Every batch, independently verified.
Each batch is analyzed by an ISO/IEC 17025 accredited third-party laboratory before it ships. This is the released report for the size selected above, exactly as the lab signed it.
Certificate of analysis
99.82%
Purity by HPLC
- Lot
- ACE-1234324
- Tested
- Sep 21, 2026
- Labeled
- 10mg
- Measured
- 10.66mg
Full QC panel
5 passed · 2 reportedPurity
HPLC · spec ≥ 95.0%
Net Peptide Content
Identity
HPLC-RTM
Fentanyl Screen
Heavy Metals
ICP-MS
Sterility
PCR
Endotoxin
USP <85>
What is Melanotan II?
Melanotan II is a synthetic seven-residue peptide built on the 4–10 fragment of alpha-melanocyte-stimulating hormone. Three changes make it far more stable than the hormone it comes from: norleucine replaces methionine, D-phenylalanine replaces the natural L form, and a lactam bridge between an aspartate and a lysine side chain closes the molecule into a ring. The C-terminus is an amide.
It came out of the University of Arizona, where Al-Obeidi, Hruby, Hadley, Dorr and colleagues designed a series of cyclic lactam melanotropins in the late 1980s. In skin-melanocyte assays the Asp/Lys lactam analogues, including the Melanotan II sequence, were around 90 to 100 times as potent as alpha-MSH. “MT2” and “MT-II” are the usual short names.
Melanotan II identity
| Names | Melanotan II, Melanotan 2, MT2, MT-II, MTII |
|---|---|
| Sequence | Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2 |
| Also written | Ac-[Nle4, Asp5, D-Phe7, Lys10]-alpha-MSH(4-10)-NH2, cyclic lactam |
| Molecular formula | C50H69N15O9 |
| Molecular weight | 1024.2 g/mol |
| CAS number | 121062-08-6 |
| PubChem CID | 92432 |
| Receptor targets | Non-selective melanocortin agonist: MC1R, MC3R, MC4R, MC5R |
| This product | 10 mg, lyophilised powder |
Sources: PubChem CID 92432; Schiöth et al., Peptides, 1997 (receptor binding).
Certificate for the current lot
The current Melanotan II lot was analysed by ILS Laboratories in San Diego, which states ISO/IEC 17025 accreditation for activities within its published scope. Identity was confirmed by HPLC retention time against a reference standard:
| Size | Lot | Laboratory | Analysed | HPLC purity | Measured content | Identity |
|---|---|---|---|---|---|---|
| 10mg | ILS Laboratories | 21 Sep 2026 | 99.82% | 10.66mg | Confirmed |
Transcribed from the certificate issued for each size on sale today. Open the signed certificate for any size under Verified test results above. Every Melanotan II COA, lot by lot
Published research on Melanotan II
- Design of the cyclic lactams (1989). Molecular-dynamics design produced cyclic alpha-MSH analogues; 23-membered rings gave the highest potency and the Asp5/Lys10 analogues showed prolonged activity in frog and lizard skin assays. Potent and prolonged acting cyclic lactam analogues of alpha-melanotropin: design based on molecular dynamics. Al-Obeidi F, et al. Journal of Medicinal Chemistry, 1989.
- Receptor selectivity (1997). Radioligand binding at human MC1, MC3, MC4 and MC5 receptors showed the cyclic lactams (MTII and SHU9119) with higher overall affinity than cyclic disulphide analogues. Selectivity of cyclic [D-Nal7] and [D-Phe7] substituted MSH analogues for the melanocortin receptor subtypes. Schiöth HB, et al. Peptides, 1997.
- Melanocortin signalling and feeding (mice, 1997). Used as an MC3/MC4 agonist given into the brain, MTII inhibited feeding in four mouse models of hyperphagia; the antagonist SHU9119 blocked the effect. A landmark paper for melanocortin neuroscience. Role of melanocortinergic neurons in feeding and the agouti obesity syndrome. Fan W, et al. Nature, 1997.
- Pilot phase 1 (1996). In three healthy men, two showed increased skin pigmentation by reflectance measurement; nausea, somnolence and a stretching-and-yawning complex were reported. Evaluation of melanotan-II, a superpotent cyclic melanotropic peptide in a pilot phase-I clinical study. Dorr RT, et al. Life Sciences, 1996.
- Crossover study (1998). A double-blind, placebo-controlled crossover study in 10 men measured erectile responses by RigiScan and reported nausea, stretching and yawning, and decreased appetite more often after Melanotan II than placebo. Synthetic melanotropic peptide initiates erections in men with psychogenic erectile dysfunction: double-blind, placebo controlled crossover study. Wessells H, et al. Journal of Urology, 1998.
- History and successors (2006). A review of the Arizona programme: Melanotan I (linear) and Melanotan II (cyclic, truncated) were patented and tested clinically, and PT-141 is described as a newer Melanotan II analogue. Melanocortin peptide therapeutics: historical milestones, clinical studies and commercialization. Hadley ME, Dorr RT. Peptides, 2006.
Regulatory status and safety reports
Melanotan II is not an approved medicine in the US; there is no Drugs@FDA application for it. The only FDA-approved alpha-MSH analogue is afamelanotide (Scenesse). FDA’s page on bulk substances that may present significant safety risks in compounding lists Melanotan II among nominated-but-withdrawn substances and cites published case reports of serious adverse events. A 2017 dermatology review describes unregulated use of Melanotan I and II and case reports of mole changes and melanoma, while noting that a causal link has not been shown. FDA: bulk drug substances that may present significant safety risks; Risks of unregulated use of alpha-melanocyte-stimulating hormone analogues: a review. Habbema L, et al. International Journal of Dermatology, 2017.
Clean Peptide sells Melanotan II as a reference material for laboratory research only, not for human or veterinary use.
Related research
- PT-141 (bremelanotide) Spray: the free-acid analogue of Melanotan II, in solution.
- KPV: the C-terminal tripeptide of alpha-MSH, Lys-Pro-Val.
- Melanocortin peptides in the catalogue.
- How to read a peptide certificate of analysis.
What is on file, and how it is handled
Every figure below is transcribed from the paperwork for this compound.
Material
- Compound
- Melanotan II
- Class
- Melanocortin receptor agonist (alpha-MSH analogue)
- Form
- Lyophilised powder
- Sizes
- 10mg
- Sequence
- Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2
- Formula
- C50H69N15O9
- CAS
- 121062-08-6
- Mol. weight
- 1024.2 g/mol
- Residues
- 7 (cyclic lactam)
Verification
- Identity
- Confirmed on the certificate of analysis
- Purity
- ≥ 99.82% by HPLCSee certificate
- Batch
- ACE-1234324See certificate
- Documentation
- Per-batch certificate of analysis
Handling
- Storage
- Store at −20 °C, protected from light
- Intended use
- In-vitro laboratory research only
QuestionsMelanotan II: frequently asked
What is MT2?+
MT2 is short for Melanotan II, a synthetic cyclic lactam analogue of alpha-MSH(4-10) with the sequence Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2.
What receptors does Melanotan II bind?+
It is a non-selective melanocortin receptor agonist. Published radioligand binding shows it binding human MC1, MC3, MC4 and MC5 receptors.
What is the difference between Melanotan II and PT-141?+
They share the same cyclic sequence. Melanotan II has a C-terminal amide (C50H69N15O9, 1024.2 g/mol); PT-141 (bremelanotide) has a free carboxylic acid (C50H68N14O10, 1025.2 g/mol).
What is the difference between Melanotan I and Melanotan II?+
Melanotan I is a linear alpha-MSH analogue; Melanotan II is a shorter, cyclic lactam analogue. Both came from the University of Arizona programme.
Is Melanotan II FDA-approved?+
No. There is no Drugs@FDA application for Melanotan II. The FDA-approved alpha-MSH analogue is afamelanotide (Scenesse).
What does the certificate for this Melanotan II show?+
The current 10 mg lot, ACE-1234324, was analysed by ILS Laboratories on 21 September 2026: 99.82% HPLC purity, 10.66 mg net peptide content and identity confirmed by HPLC retention time.
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