Made in USA · ≥99% HPLC
Melanocortin Peptide
Melanotan-II 10mg
MT-IIMT-2MC1R–MC5R agonist
A cyclic heptapeptide α-MSH analog and non-selective melanocortin (MC1R–MC5R) agonist, supplied as 10 mg freeze-dried powder for in-vitro melanocortin-pathway research.
$59.95
28 in stock
For laboratory and research use only. Not for human consumption.
This product is not a drug, food or cosmetic. It is sold exclusively to qualified researchers and licensed laboratories.
28 in stock
Tested by Freedom Diagnostics TestingHPLC purity + LC-MS identityLot-matched COA on-site
Arrives in 3–5 days
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US-synthesizedMade & lab-released in the United States
Independent COAThird-party Certificate of Analysis per lot
HPLC + LC-MSPurity by HPLC, identity by mass spectrometry
Same-day dispatchOrders before 2 PM CT ship the same business day
What is Melanotan-II?
Melanotan-II is a cyclic heptapeptide α-MSH analog and non-selective melanocortin receptor agonist (MC1R to MC5R). It was designed at the University of Arizona in the late 1980s as a conformationally constrained analog of α-MSH. The ring comes from a lactam bridge between Asp and Lys, which makes the peptide more compact and more resistant to enzymatic degradation than the linear parent sequence.
Laboratories use it in melanocortin receptor pharmacology: cAMP signaling and receptor-selectivity assays in MC1R- and MC4R-expressing cells, and structure-activity comparisons with linear α-MSH. The material supplied here is research-grade for in vitro laboratory study only.
Every lot, independently verified
Independently third-party tested and matched to the lot ID printed on your vial. Values below are from the latest released lot.
99.81%
HPLC-UV Purity
Passed full QC panel
Independent third-party lab (Freedom Diagnostics Testing)
View COA (PDF)
Latest batch · tested 23 Mar 2026 · Freedom Diagnostics (USA)
Lot details
ProductMelanotan-II 10 mg
LotYellow Cap
AppearanceWhite lyophilized powder
Accession #2603200301
Reported23 Mar 2026
Full QC panel · third-party lab7 assays
Purity (HPLC-UV)99.81% ✓
Identity (LC-MS)Melanotan-II ✓
HPLC conformity (2×)Confirmed ✓
Net content10.34 mg ✓
Heavy metals (ICP-MS)Not Detected ✓
SterilityNo Growth ✓
Endotoxin (USP <85>)Within limits ✓
Every lot is released against Koi's full QC panel — HPLC purity, LC-MS identity, net content, heavy metals, sterility, and endotoxin — by an independent third-party laboratory (Freedom Diagnostics Testing). Values shown are from the latest released lot and vary batch to batch. The lot-specific certificate is published in our public COA library and matched to the lot ID printed on the vial.
Browse full COA library →
Compound information
Chemical & structural reference data — specifications, molecular profile and handling.
Product Specifications
CompoundMelanotan-II (cyclic α-MSH analog, non-selective melanocortin agonist)
Vial size10 mg
Purity≥99% by HPLC
Identity confirmationMass spectrometry
FormFreeze-dried powder, white to off-white
Appearance in solutionClear, colorless solution
ManufacturingMade and freeze-dried in the United States
Quality testingIndependent third-party laboratory release (Freedom Diagnostics Testing)
Molecular Profile
SequenceAc-Nle-c[Asp-His-D-Phe-Arg-Trp-Lys]-NH₂ (cyclic 2-7)
Molecular formulaC₅₀H₆₉N₁₅O₉
Molecular weight1024.2 g/mol
CAS number121062-08-6
PubChem CID92432
Other namesMT-II, MT-2, MTII, Melanotan 2
Structure classCyclic heptapeptide · lactam bridge · MC1R/MC3R/MC4R/MC5R agonist
Storage & Handling
AppearanceFreeze-dried white to off-white powder
SolubilityWater; dilute acetic acid if slow to dissolve
Storage · powder−20 °C, sealed, dark (−80 °C long-term)
In solution2–8 °C; aliquot & freeze, avoid freeze-thaw
Melanotan-II Mechanism of Action
- Non-selective agonist at four of the five melanocortin receptors (MC1R, MC3R, MC4R and MC5R), with little activity at MC2R.
- Receptor activation couples to Gs and raises intracellular cAMP, the standard read-out in melanocortin receptor assays.
- Broader receptor coverage than linear α-MSH analogs with MC1R preference, which makes it a common reference agonist in selectivity panels.
- A lactam bridge plus the Nle4 and D-Phe7 substitutions increase conformational rigidity and resistance to proteolysis compared with α-MSH.
Melanotan-II Research Applications
- Melanocortin receptor pharmacology — a standard non-selective reference agonist for MC1R, MC3R, MC4R and MC5R in cAMP and receptor-binding assays.
- cAMP signaling and receptor-selectivity assays in MC1R- and MC4R-expressing cell lines.
- Structure-activity comparisons with linear α-MSH and other melanocortin analogs to study how the cyclic constraint affects potency and selectivity.
- Competitive-binding and functional assays used to characterise new melanocortin receptor ligands.
Why Buy Melanotan-II from Koi Peptides?
- Every batch of Koi Melanotan-II is made and freeze-dried inside the United States, then released against independent third-party laboratory (Freedom Diagnostics Testing) testing.
- Each lot is checked for purity by HPLC, verified for structure by mass spectrometry, and screened for endotoxin before it goes on sale.
- The lot ID is printed on every vial and ties back to a public COA library, so researchers can verify documentation before they buy and after the vial arrives.
- Orders placed before 2 PM CT ship the same business day, and shipping is free on orders over $200.
References
The laboratory and preclinical research behind Melanotan-II — cited for scientific context.
PNAS
4-Norleucine, 7-D-phenylalanine-α-MSH: a highly potent α-melanotropin with ultralong biological activity
J. Am. Chem. Soc.
Design of a new class of superpotent cyclic α-melanotropins based on quenched dynamic simulations
Endocrine Reviews
Studies on the physiological functions of the melanocortin system
View all references +
- Sawyer, T.K., Sanfilippo, P.J., Hruby, V.J., et al. (1980). 4-Norleucine, 7-D-phenylalanine-α-melanocyte-stimulating hormone: a highly potent α-melanotropin with ultralong biological activity. PNAS, 77(10), 5754–5758. doi.org/10.1073/pnas.77.10.5754
- Al-Obeidi, F., Hadley, M.E., Pettitt, B.M., & Hruby, V.J. (1989). Design of a new class of superpotent cyclic α-melanotropins based on quenched dynamic simulations. Journal of the American Chemical Society, 111(9), 3413–3416.
- Cone, R.D. (2006). Studies on the physiological functions of the melanocortin system. Endocrine Reviews, 27(7), 736–749.
Regulatory Status
Regulatory status — provided for research context.
Regulatory Status
Regulatory status — provided for research context.
FDA Status
Melanotan-II is not approved by the FDA for any indication. Koi Peptides supplies it solely as a laboratory research reagent; it is not formulated, packaged or labeled as a drug, food or cosmetic.
Disclaimer
For laboratory and research use only. Not for human consumption. This product is not a drug, food or cosmetic. It is sold exclusively to qualified researchers and licensed laboratories. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.
Frequently Asked Questions About Melanotan-II
What does Melanotan-II do in research?+
Melanotan-II is used as a reference agonist in melanocortin receptor pharmacology. Researchers measure receptor activation through cAMP signaling and receptor-binding assays in MC1R-, MC3R-, MC4R- and MC5R-expressing cells, and use it in structure-activity comparisons with linear α-MSH.
Which receptors does Melanotan-II act on?+
It activates four of the five melanocortin receptors: MC1R, MC3R, MC4R, and MC5R, with little action at MC2R. Activity across all four is what makes it a non-selective agonist and a common reference compound in receptor-selectivity panels.
What purity is Koi's Melanotan-II?+
≥99% by HPLC (latest lot 99.81%), with identity confirmed by mass spectrometry. An independent third-party lab tests every batch, and that COA is posted in our public COA library under the lot number printed on the vial.
How do I prepare a Melanotan-II solution for research?+
Dissolve it in sterile water or a suitable buffer; a small amount of dilute acetic acid helps if a sample is slow to dissolve. Build a stock at the concentration your assay needs and add it to buffer or medium just before use. For sterile work, pass the stock through a 0.22 µm filter and keep any leftover cold.
What is the CAS number for Melanotan-II?+
CAS 121062-08-6, PubChem CID 92432. It has the formula C₅₀H₆₉N₁₅O₉ and a molecular weight of about 1024.2 g/mol. It is a cyclic seven-amino-acid peptide, Ac-Nle-c[Asp-His-D-Phe-Arg-Trp-Lys]-NH₂.
How is Melanotan-II different from PT-141 and afamelanotide?+
All three trace back to α-MSH. Afamelanotide (Melanotan-I) is a linear analog with MC1R preference. PT-141 (bremelanotide) is a cyclic analog with MC4R preference. Melanotan-II is the cyclic, non-selective analog that activates several melanocortin receptors at once.
How should Melanotan-II be stored?+
Keep the freeze-dried peptide at −20 °C, sealed and out of light; −80 °C is better for long-term storage. After it is dissolved, refrigerate at 2–8 °C and use within a few days, or aliquot and freeze at −20 °C or below. Try to thaw a vial only once.
Is Melanotan-II for human or animal use?+
No. Melanotan-II is for laboratory and research use only and is not for human consumption. It is sold exclusively to qualified researchers and licensed laboratories.
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