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Cyclic Melanocortin Agonist · MC1R/MC3R/MC4R Research

Melanotan II
Research Compound

Synthetic cyclic heptapeptide melanocortin analog developed at the University of Arizona. Non-selective agonist at MC1R, MC3R, MC4R, and MC5R receptor subtypes. Available for in vitro and preclinical research use.

10mg Vial
COA · Krause Analytical
Sabrina Runbeck PA-C
Finnrick Pulse
HPLC + MS Verified
Order Melanotan II View COA
For research use only. Not for human use.  Melanotan II is a research compound supplied for laboratory and preclinical investigational purposes exclusively. Not approved by the FDA for human use or veterinary application.
Overview

What Is Melanotan II?

Melanotan II (MT-2) is a synthetic cyclic heptapeptide analog of alpha-melanocyte-stimulating hormone (α-MSH), an endogenous melanocortin peptide. Its structure is defined by a lactam-bridged cyclic core: Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2.

MT-2 was developed in the early 1980s at the University of Arizona in the laboratory of Victor Hruby, Ph.D., whose group pioneered structure-activity relationship research on melanocortin peptide analogs. The cyclic constraint was engineered to improve metabolic stability and receptor binding relative to the linear native α-MSH sequence.

As a non-selective melanocortin receptor agonist, MT-2 engages MC1R, MC3R, MC4R, and MC5R subtypes. This broad receptor profile distinguishes it from linear analogs such as Melanotan I (afamelanotide), which shows greater selectivity toward MC1R in published research models.

Published research has examined MT-2 across melanocortin receptor pharmacology, including MC1R melanogenesis pathway studies, MC3R/MC4R energy homeostasis research in preclinical models, and MC4R hypothalamic mechanism investigations. It is a widely referenced tool compound in melanocortin receptor biology.

Chemical Specifications
Compound Name Melanotan II (MT-2)
Type Cyclic heptapeptide
Sequence Ac-Nle-cyclo[Asp-His-
D-Phe-Arg-Trp-Lys]-NH₂
Molecular Formula C₅₀H₆₉N₁₅O₉
Molecular Weight ~1024 Da
CAS Number 121062-08-6
Origin University of Arizona
Receptor Targets MC1R, MC3R, MC4R, MC5R
Purity ≥99% (HPLC + MS)
Research Size 10mg vial (lyophilized)
Published Research

Research Background

Published research has examined Melanotan II across multiple melanocortin receptor contexts. The following areas represent representative themes in the peer-reviewed literature.

MC1R Research

MC1R Melanogenesis Pathway Research

Published research has examined MT-2 binding at the MC1R subtype and its role as a tool compound in melanogenesis pathway studies. MC1R-focused research evaluates receptor activation kinetics, second-messenger signaling through cAMP, and downstream effector engagement in cell-based models.

MC3R / MC4R Research

MC3R/MC4R Energy Metabolism Research in Preclinical Models

MC3R and MC4R receptor subtypes have been studied in the context of energy homeostasis in preclinical animal models. Published research has examined MT-2 as a reference agonist in these investigations, comparing receptor engagement profiles at MC3R versus MC4R across experimental paradigms.

MC4R Mechanism Research

MC4R Hypothalamic Mechanism Research

Published research has examined hypothalamic MC4R receptor mechanisms using MT-2 as a non-selective agonist reference standard. Research in this area has explored receptor distribution, intracellular signaling cascades, and receptor occupancy dynamics in rodent preclinical models.

Receptor Subtype Research

Melanocortin Receptor Subtype Selectivity Research

Because MT-2 engages all four peripheral and central melanocortin receptor subtypes (MC1R, MC3R, MC4R, MC5R), it has been widely used in comparative receptor selectivity research alongside more selective analogs. Published research has characterized its binding affinity and functional potency profiles across receptor subtypes.

Peptide Chemistry

Cyclic Peptide Structure-Activity Relationship Research

The cyclic lactam scaffold of MT-2 has been the subject of structure-activity relationship (SAR) research examining how conformational constraint influences receptor binding, metabolic stability, and pharmacological profile. MT-2 serves as a reference cyclic analog in broader melanocortin peptide SAR programs.

Search PubMed: Melanotan II Melanocortin Receptor Publications
Sequence Labs Supply

Melanotan II — Research Sample

Melanotan II · 10mg Lyophilized Vial
Cyclic heptapeptide · CAS 121062-08-6 · For research use only
Size 10mg per vial (lyophilized powder)
Purity ≥99% verified by HPLC and mass spectrometry
Testing Lab Krause Analytical — independent third-party COA on every batch
Catalog Review Reviewed by Sabrina Runbeck, PA-C for catalog integrity
Distribution Finnrick Pulse distribution network
Storage Lyophilized: −20°C long-term; 4°C short-term in sealed vial
Use For research use only. Not for human use.
HPLC Verified Mass Spec Verified Krause COA Sabrina Runbeck PA-C Finnrick Pulse
Research Price
~$45
per 10mg vial
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Laboratory Reference

Reconstitution Reference

Standard laboratory procedure for preparing Melanotan II lyophilized research sample. For research use only.

1
Prepare the sterile workspace
Establish a sterile working environment consistent with your laboratory's aseptic technique protocols. Allow the lyophilized vial to equilibrate to room temperature before opening.
2
Select the appropriate solvent
Bacteriostatic water (0.9% benzyl alcohol in sterile water for injection) is the standard solvent used in published research protocols for lyophilized peptide reconstitution. The volume of solvent introduced determines the resulting research sample concentration — consult your specific research protocol for target concentration.
3
Introduce solvent to the vial
Using a suitable research-grade syringe, introduce the solvent volume slowly along the inside wall of the vial, directing solvent against the glass rather than directly onto the lyophilized cake. This minimizes mechanical disruption of the peptide matrix.
4
Allow dissolution
Gently swirl — do not vortex — the vial until the lyophilized powder is fully dissolved. The resulting solution should appear clear. Do not apply heat. If the powder does not dissolve after gentle agitation, allow the vial to sit at room temperature for 5–10 minutes before resuming gentle mixing.
5
Label and store the reconstituted sample
Label the reconstituted vial with compound name, concentration, date of reconstitution, and researcher initials per your laboratory's inventory management protocols. Store reconstituted research sample at 4°C and use within the timeframe specified by your institutional guidelines.
Research Use Only. This reconstitution reference is provided as a laboratory informational guide for qualified researchers. Melanotan II from Sequence Labs is not for human use, not for veterinary use, and not for consumption of any kind. All handling should comply with your institution's research protocols and applicable regulations.

Frequently Asked Questions

Melanotan II (MT-2) is a synthetic cyclic heptapeptide analog of alpha-melanocyte-stimulating hormone (α-MSH). Its full sequence is Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH₂, molecular formula C₅₀H₆₉N₁₅O₉, molecular weight approximately 1024 Da, CAS 121062-08-6. Developed at the University of Arizona by Victor Hruby's laboratory, it is a non-selective agonist at MC1R, MC3R, MC4R, and MC5R melanocortin receptor subtypes. It is supplied by Sequence Labs strictly for in vitro and preclinical research purposes.
Melanotan I (afamelanotide) is a linear analog of α-MSH, while Melanotan II is a cyclic heptapeptide. The cyclic lactam bridge in MT-2 confers enhanced metabolic stability and altered receptor binding geometry compared to Melanotan I. In published research models, Melanotan I demonstrates more selective engagement at MC1R, while MT-2 engages MC1R, MC3R, MC4R, and MC5R more broadly — making MT-2 a more useful tool compound for non-selective melanocortin receptor research contexts.
Published research has examined MT-2 in the following research contexts: (1) MC1R melanogenesis pathway research in cell-based models; (2) MC3R/MC4R energy homeostasis research in preclinical animal models; (3) MC4R hypothalamic mechanism research using MT-2 as a non-selective reference agonist; (4) melanocortin receptor subtype selectivity studies comparing MT-2 to more selective analogs; (5) cyclic peptide structure-activity relationship research examining how the lactam bridge influences receptor pharmacology. A full index of published literature is searchable at PubMed.
PT-141 (bremelanotide) is a metabolite formed from Melanotan II when the cyclic lactam bond undergoes hydrolysis. Structurally, PT-141 is the open-chain version of MT-2's cyclic core. In published research, PT-141 has been studied with a focus on MC3R and MC4R receptor subtypes rather than the broader MC1R/MC3R/MC4R/MC5R profile of MT-2. Researchers studying receptor subtype selectivity often evaluate both compounds in parallel. Sequence Labs supplies PT-141 separately as a 10mg research sample.
For laboratory research purposes, Melanotan II lyophilized powder is typically prepared by introducing bacteriostatic water as solvent to the sealed vial. Sterile technique is maintained throughout. Solvent is introduced slowly along the vial wall — not directly onto the lyophilized cake — using an appropriate research-grade syringe. The vial is gently swirled until the lyophilized powder is fully dissolved. The reconstituted research sample should be labeled with compound name, concentration, and date, then stored at 4°C consistent with institutional research protocols. For research use only.
No. Melanotan II supplied by Sequence Labs is strictly for in vitro laboratory research and qualified preclinical research use only. It is not approved by the Food and Drug Administration for human use, is not a pharmaceutical product, and is not intended to diagnose, treat, cure, or prevent any disease or condition in humans or animals. Any use outside of qualified research contexts is outside the stated purpose of this research compound.

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