Melanotan II — Melanocortin Research

Last updated: May 2026

Melanotan II is a synthetic cyclic heptapeptide analog of alpha-melanocyte-boosting hormone (alpha-MSH). It was designed to study pigment signal receptor (MCR) drug action with greater strength. Longer duration than native alpha-MSH. Alpha-MSH is a 13-amino-acid peptide produced from the POMC gene. It triggers five pigment signal receptor subtypes (MC1R through MC5R). Melanotan II uses a cyclic 7-amino-acid structure to achieve higher receptor binding across many MCR subtypes. According to a study in Peptides (1998). Melanotan II produced clear skin color responses in rodent models at levels ten times lower than those needed for native alpha-MSH.

Next Level Pharm supplies research-grade Melanotan II tested to at least 99 percent purity by HPLC. Mass spec on every batch. A Certificate of Test ships with every lot for full tracking.

The sections below cover Melanotan II structure, its receptor link profile. Skin color research, MC4R CNS research, check with Melanotan I. What experts should check before sourcing.

Key Takeaways

What it is: Melanotan II is a cyclic synthetic heptapeptide. It binds pigment signal receptors MC1R through MC5R with higher strength than native alpha-MSH.
MC1R and skin color: Cell. Animal studies link MC1R trigger by Melanotan II to increased melanin output in melanocytes. This produces trackable skin color changes in treated rodents.
MC4R and CNS research: Brain-expressed MC4R mediates effects on appetite control. Sex function function markers in animal models treated with Melanotan II.
Cyclic structure: The cyclic 7-amino-acid structure gives Melanotan II a longer half-life than the linear Melanotan I structure. It also shows higher energy strength in animals how the body uses it studies.
Sourcing standard: Research-grade Melanotan II needs HPLC purity above 99 percent. Mass spec check of cyclic structure. A lot-exact COA.

Here is a closer look at Melanotan II receptor drug action, published research findings, and sourcing standards.

What Is Melanotan II and How Was It Developed?

Melanotan II was developed at the Institute of Arizona in the late 1980s. Early 1990s as part of a research program studying pigment signal system drug action. The goal was to create a stable. Potent MCR agonist with a longer half-life than native alpha-MSH. Is rapidly degraded in circulation by proteases.

The structural approach used a cyclic disulfide bridge between residues 4. 10 of the alpha-MSH pharmacophore core chain His-Phe-Arg-Trp. This cyclization created a in shape constrained structure that resists enzymatic breakdown. The resulting 7-amino-acid cyclic peptide Ac-Nle-c[Asp-His-D-Phe-Arg-Trp-Lys]-NH2 showed greatly higher strength. Half-life than alpha-MSH in cell binding assays. According to a pharmacology study in Biochemical Pharmacology (1994). The cyclic design produced a 100-fold increase in receptor link strength compared to the linear analog at MC1R.

How Does Melanotan II Bind Melanocortin Receptors?

The five pigment signal receptor subtypes (MC1R through MC5R) are G protein-coupled receptors. It signals through cyclic AMP (cAMP) pathways. Each subtype is expressed in different tissues and mediates distinct living effects. MC1R is expressed on melanocytes and determines skin color responses. MC3R and MC4R are expressed in the brain base and limbic system. MC5R is expressed in exocrine glands.

Melanotan II binds all five subtypes but with highest binding at MC1R, MC3R, and MC4R. The His-D-Phe-Arg-Trp core chain mimics the binding motif of native alpha-MSH. It contacts the receptor link pocket. The substitution of D-Phe (D-phenylalanine) for L-Phe at this position in Melanotan II increases receptor binding by roughly tenfold in binding assays. According to a receptor binding study in the European Journal of Pharmacology (2000). Melanotan II’s Ki at MC1R was about 0.2 nM in cell membrane preparations. Compared to 2.5 nM for native alpha-MSH.

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What Does Pigmentation Research Show for Melanotan II?

According to a study in Peptides (1998). Melanotan II produced clear darkening of fur skin color in the Agouti mouse model at levels ten times lower than those needed for native alpha-MSH. The Agouti mouse model is a standard system for studying MC1R-driven skin color. These mice have a genetic suppression of MC1R that produces yellow fur. MCR agonists restore the dark skin color cell type.

The pathway involves MC1R trigger on melanocytes, which triggers a cAMP cascade. It raises tyrosinase, the key enzyme in melanin biosynthesis. Increased tyrosinase action leads to higher melanin output in the melanosome organelles of the melanocyte. The melanin is then transferred to adjacent skin cells to produce visible skin color changes. These steps have been studied in isolated human melanocyte cell cultures as well as in vivo rodent models.

What Does MC4R Research Show for Melanotan II?

MC4R is expressed in the nearby nucleus. Other brain-based regions that control energy balance and sex function function. Animal studies using Melanotan II have examined its effects in these brain circuits. MC4R knockout mouse studies have been used to confirm. Its effects are mainly MC4R-driven and which involve other receptor subtypes.

According to a study in Science (1998). ICV injection of Melanotan II produced erection in male rats through an MC4R-driven pathway in the brain base. The study used MC4R-selective agonists and antagonists to confirm the receptor focus. These findings established Melanotan II as a key research tool for studying MC4R function in sex function brain science. Separate from its skin color research applications at MC1R.

How Does Melanotan II Compare to Melanotan I in Research?

Melanotan I is a linear 13-amino-acid analog of alpha-MSH that mainly targets MC1R. It was the first synthetic alpha-MSH analog studied for skin color science. Its linear structure is less metabolically stable than Melanotan II. Giving it a shorter half-life in animals, how the body uses it studies.

Melanotan II’s cyclic structure and broader receptor profile separate it from Melanotan I in several ways. First, Melanotan II has action at MC3R, MC4R, and MC5R beyond MC1R. This makes it useful for studying many MCR-dependent pathways together, or for studies. It needs a broad MCR agonist. Second, the cyclic structure produces a longer duration of receptor occupancy. According to a comparative pharmacology study in Peptides (2001). Melanotan II remained active in rodent models at 24 hours post-use while Melanotan I action declined greatly by 8 hours.

What Quality Standards Apply to Research-Grade Melanotan II?

Research-grade Melanotan II needs HPLC purity above 99 percent. The cyclic structure with its disulfide bridge adds output complexity. During output, the disulfide bond can form between non-target cysteine groups or fail to form correctly. Producing linear byproducts or wrongly cyclized variants. These variants have different receptor link profiles and would confound MCR-exact lab results.

Mass spec confirms that the measured molecule weight matches the correctly cyclized structure. A lot-exact COA records both HPLC and mass spec results with a traceable lot number. For Melanotan II mainly. Cyclization check is the most critical quality control step beyond basic purity measurement. Since linear or wrongly folded variants may pass basic purity tests while lacking the correct research-grade profile.

Frequently Asked Questions

What is Melanotan II?

Melanotan II is a synthetic cyclic heptapeptide analog of alpha-melanocyte-boosting hormone (alpha-MSH). It binds pigment signal receptors with higher strength and longer duration than native alpha-MSH. Research-grade Melanotan II is studied in lab models of pigment signal receptor drug action, skin color science. Sexual function brain science.

What receptors does Melanotan II bind?

Melanotan II binds pigment signal receptors MC1R through MC5R with varying binding. It shows highest strength at MC1R, which controls melanin output, and at MC3R. MC4R, which are expressed in the brain and linked to appetite and sex function function research. Its broad receptor profile is why it produces many effects across different tissue types in animal models.

What does Melanotan II pigmentation research show?

Published studies in rodent and cell models report. Melanotan II triggers MC1R on melanocytes, boosting melanin output and increasing skin color in treated animals. According to a study in Peptides (1998). Melanotan II produced clear skin color increases in mice at lower levels than alpha-MSH. Reflecting its higher receptor link binding. Longer half-life.

What does Melanotan II MC4R research show?

MC4R is expressed in the brain base and other brain regions. Animal studies report that Melanotan II triggers this receptor. Produces effects on appetite control and sexual function markers in rodent models. Published research has used MC4R knockout mice to confirm. CNS effects are driven mainly through MC4R triggers rather than other receptor subtypes.

How does Melanotan II compare to Melanotan I in research?

Melanotan I is a linear 13-amino-acid analog of alpha-MSH that mainly targets MC1R. Melanotan II is a cyclic 7-amino-acid analog with broader receptor link across MC1R, MC3R, MC4R. MC5R. The cyclic structure gives Melanotan II higher energy strength. A longer half-life in animal models. Remaining active at 24 hours where Melanotan I action declines by 8 hours.

What purity standard applies to research-grade Melanotan II?

Research-grade Melanotan II needs HPLC purity above 99 percent. Mass spec check of the cyclic heptapeptide molecule weight. Cyclization check by mass spec is critical since linear or wrongly folded variants may pass purity tests while lacking the correct research-grade profile. A lot-exact COA with both results provides the standard for traceable lab research.

Is Melanotan II for human use?

The research-grade compound is for lab research only. It is not approved for human use, therapeutic, or diagnostic purposes. control agencies in many countries have issued warnings against non-trial-based use of synthetic pigment signal peptides. All research cited here used cell or animal models. The compound should not be used outside of a licensed research setting.

Where does Melanotan II ship from?

Research-grade Melanotan II ships to all 50 states within the United States. A Certificate of Test with HPLC purity data, mass spec results. Lot number ships with every order to provide full sourcing records for lab research.

Summary

Melanotan II is a cyclic synthetic heptapeptide. It binds pigment signal receptors MC1R through MC5R with high strength and energy strength. Published research links MC1R trigger to increased melanin output in skin color models. MC4R triggers sex function and appetite control findings in rodent studies. Its cyclic structure provides longer duration. Higher receptor binding than native alpha-MSH or linear analog Melanotan I. Research-grade sourcing needs HPLC purity above 99 percent, mass spec cyclization check, and a lot-exact COA.

What Should You Do Next?

Browse research-grade Melanotan II at Next Level Pharm for COA-tested options with full HPLC. Mass spec data on every batch.

About the Author

Next Level Pharm Research Team

Alex M covers peer-reviewed findings in peptide science for Next Level Pharm, a US-based supplier of research-grade peptides verified to >=99% purity via HPLC and mass spectrometry on every batch.

Disclaimer: The information provided on this page is for educational and research purposes only. Next Level Pharm’s products are intended for laboratory research use only. They are not intended for human consumption, diagnostic, therapeutic, or medicinal purposes. This content does not constitute medical advice. Always consult a licensed healthcare professional before making any health-related decisions.

Melanotan II Research: Melanocortin Receptor Pharmacology Overview