This is a working overview of MC1R, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-07-19 and is reviewed periodically as new material appears.
Melanotan-2, also written Melanotan II, is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone. Its sequence is Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, and the lactam bridge between the aspartate and lysine side chains constrains the peptide into a ring. This structural change increases receptor affinity and metabolic stability relative to the native hormone. The compound was created in the 1980s as a research tool for studying pigmentation biology.
Melanocytes are the pigment-producing cells of the skin, and they carry melanocortin-1 receptors on their surface. When the receptor is activated, cyclic adenosine monophosphate rises inside the cell and raises the activity of enzymes such as tyrosinase, which increases melanin output. Melanotan-2 binds melanocortin-1 receptors in vitro and in animal models, and this binding is generally described as the basis for the tanning effect. Other receptors account for different effects: melanocortin-4 receptors contribute to appetite and erectile signalling, while melanocortin-3 and melanocortin-5 receptors contribute to energy balance and exocrine function.
Analytical confirmation of identity relies on mass spectrometry, most often coupled to liquid chromatography. Reversed-phase high-performance liquid chromatography separates the peptide from related impurities and provides a purity estimate based on peak area. Electrospray ionization mass spectrometry then confirms the expected molecular mass, while tandem mass spectrometry can map the fragment sequence. For research-grade material, these two techniques together form the standard minimum. Purity figures reported by vendors are frequently not traceable to an independent laboratory.
Independent verification is central to quality control because the compound is not produced under pharmaceutical manufacturing standards. Third-party laboratories can measure purity, identity, residual solvents, and microbial contamination, though the scope of testing varies between services. Reported analyses of vendor samples have shown batch-to-batch variation in peptide content and the presence of truncated or oxidized species. How much of this variation reflects synthesis conditions versus storage and shipping is not well characterized. No harmonized reference standard exists for the material as sold.
| Property | Value | Notes |
|---|---|---|
| Compound class | Synthetic cyclic heptapeptide | Alpha-MSH analogue containing a D-phenylalanine residue |
| Molecular formula | C50H69N15O9 | Average molecular mass approximately 1024.2 g/mol |
| Appearance | White to off-white lyophilised powder | Normally supplied as a freeze-dried solid in a sealed vial |
| Solubility | Freely soluble in water and polar solvents | Dissolves readily in aqueous buffers and in alcohol-water mixtures |
| Receptor targets | MC1R, MC3R, MC4R, MC5R | Acts as a non-selective melanocortin receptor agonist |
The compound was developed in the late 1980s and early 1990s by academic researchers investigating melanocortin signaling and pigmentation. Early work explored whether synthetic analogs could reproduce effects of the natural hormone under controlled conditions. The molecule never advanced through the full regulatory pathway required for approval as a medicine. From the mid-2000s onward it appeared in unregulated consumer markets, often distributed through informal channels. That gap between research origins and commercial availability shapes how the compound is discussed today.
Melanotan-2 is a synthetic peptide designed as an analog of alpha-melanocyte-stimulating hormone, a signaling molecule produced in the pituitary and skin. Its structure is a linear chain of seven amino acids that folds into a ring through an internal lactam bridge joining two side chains. The compound is sometimes written as MT-II or MEL-2 in informal and commercial contexts. It belongs to the melanocortin peptide family, a group of short signaling molecules that share a conserved core sequence recognized by melanocortin receptors.
Two structural changes distinguish the synthetic peptide from the natural hormone. A norleucine residue replaces methionine at one position, and a D-configured phenylalanine replaces the natural L-form at another. Both substitutions slow enzymatic breakdown, which extends the molecule's persistence relative to the parent hormone. The lactam bridge further constrains the backbone into a stable conformation. These features are standard design strategies in peptide chemistry and are not unique to this compound; they appear across many research peptides built for improved stability.
Identity and purity are assessed mainly by reversed-phase high-performance liquid chromatography with ultraviolet detection, often paired with mass spectrometry. Retention time supports identity, while the mass spectrum confirms the molecular weight of the intact peptide. Purity is frequently reported as a percentage of total peak area, a figure that depends on the wavelength, column and gradient used. Impurity profiling may also look for truncated sequences, oxidised forms and residual counterions. Amino acid analysis and peptide mapping provide orthogonal confirmation when required.
Regulatory status varies by jurisdiction, and the substance is frequently described as unapproved for therapeutic use. Some authorities classify it alongside prescription-only medicines or controlled categories, while others address it through general consumer protection rules. Analytical surveys have reported mismatches between label claims and measured content in products sold online, although the scope of such testing is limited. Whether these discrepancies are widespread remains an open question. Discussion in the literature therefore tends to combine chemistry, supply-chain observation and policy analysis.
One average square inch (6.5 cm2) of skin holds 650 sweat glands, 20 blood vessels, 60,000 melanocytes, and more than 1,000 nerve endings. The average human skin cell is about 30 μm in diameter, ranging from 25 to 40 μm2, depending on a variety of factors. Skin is composed of three primary layers: the epidermis, the dermis and the hypodermis (more commonly called the subcutaneous layer).
== Duration of the effect == The EPOC effect is greatest soon after the exercise is completed and decays to a lower level over time. One experiment, involving exertion above baseline, found EPOC increasing metabolic rate to an excess level that decays to 13% three hours after exercise, and 4% after 16 hours, for the studied exercise dose. Another study, specifically designed to test whether the effect existed for more than 16 hours, conducted tests for 48 hours after the conclusion of the exercise and found measurable effects existed up to the 38-hour post-exercise measurement, for the studied exercise dose.
=== Event appearances === Pert was honored by the New York Open Center on November 7, 2006, for her "leadership across the bridge between science and heart." Pert received the first time award of the Theophrastus Paracelsus Foundation in Holistic Medicine for her pioneering work in the area of psychoneuroimmunology (St Gallen, Switzerland) on April 12, 2008.
== Diagnosis == Typical scleroderma is classically defined as symmetrical skin thickening, with about 70% of cases also presenting with Raynaud's phenomenon, nail-fold capillary changes, and antinuclear antibodies. Affected individuals may experience systemic organ involvement. No single test for scleroderma works all of the time; hence, diagnosis is often a matter of exclusion. Atypical scleroderma may show any variation of these changes without skin changes or with finger swelling only. Laboratory testing can show antitopoisomerase antibodies, like anti-scl70 (causing a diffuse systemic form), or anticentromere antibodies (causing a limited systemic form and the CREST syndrome). Other autoantibodies can be seen, such as anti-U3 or anti-RNA polymerase. Antidouble-stranded DNA autoantibodies are likely to be present in serum.
Sources: en.wikipedia.org
23 March to 3 April The 3rd Battalion, 9th Marines and elements of the 1st Brigade, 5th Infantry Division launch Operation Montana Mauler against the PAVN 27th Regiment north of Firebase Fuller in Quảng Trị Province. The operation results in 271 PAVN killed, U.S. losses are 38 killed.
The carryover effect is a term used in clinical chemistry to describe the transfer of unwanted material from one container or mixture to another. It describes the influence of one sample upon the following one. It may be from a specimen, or a reagent, or even the washing medium. The significance of carry over is that even a small amount can lead to erroneous results.
Over the years, a variety of methods have been developed to refine the use of solid-phase organic synthesis in combinatorial chemistry, including efforts to increase the ease of synthesis and purification, as well as non-traditional methods to characterize intermediate products. Although the majority of the examples described here will employ heterogeneous reaction media in every reaction step, Booth and Hodges provide an early example of using solid-supported reagents only during the purification step of traditional solution-phase syntheses. In their view, solution-phase chemistry offers the advantages of avoiding attachment and cleavage reactions necessary to anchor and remove molecules to resins, as well as eliminating the need to recreate solid-phase analogues of established solution-phase reactions. The single purification step at the end of a synthesis allows one or more impurities to be removed, assuming the chemical structure of the offending impurity is known. While the use of solid-supported reagents greatly simplifies the synthesis of compounds, many combinatorial syntheses require multiple steps, each of which still requires some form of purification. Armstrong, et al. describe a one-pot method for generating combinatorial libraries, called multiple-component condensations (MCCs). In this scheme, three or more reagents react such that each reagent is incorporated into the final product in a single step, eliminating the need for a multi-step synthesis that involves many purification steps.
== See also == List of herbs with known adverse effects Alcohol and Drugs History Society Betel Domesticated plants and animals of Austronesia Kava culture Nakamal Paan Samoa 'ava ceremony Samoan plant names
Waqar, Saiama N.; Redman, Mary W.; Arnold, Susanne M.; Hirsch, Fred R.; Mack, Philip C.; Schwartz, Lawrence H.; et al. (May 2021). "A Phase II Study of Telisotuzumab Vedotin in Patients With c–MET-positive Stage IV or Recurrent Squamous Cell Lung Cancer (LUNG-MAP Sub-study S1400K, NCT03574753)". Clinical Lung Cancer. 22 (3): 170–177. doi:10.1016/j.cllc.2020.09.013. ISSN 1525-7304. PMC 8044254. PMID 33221175.
Sources: en.wikipedia.org
No. It is a laboratory-made peptide, while the natural hormone is alpha-melanocyte-stimulating hormone, a longer peptide produced by the pituitary gland and by skin cells. Melanotan-2 mimics only a short active region of that hormone and contains non-natural residues such as D-phenylalanine.
No approved regulatory indication exists in major markets. An approval exists for a different peptide, afamelanotide, which is used for a rare photosensitivity disorder called erythropoietic protoporphyria. Melanotan-2 itself remains a research compound with no cleared clinical role.
Melanocortin-1 receptors on melanocytes are the receptor most closely linked to pigment production. The peptide is not selective, however, and also activates melanocortin-3, melanocortin-4, and melanocortin-5 receptors. That lack of selectivity is the usual explanation offered for both its range of observed effects and its off-target effects.
The lyophilized powder is generally held at minus twenty degrees Celsius or below, away from light and moisture. Reconstituted solutions are typically refrigerated and used quickly. These practices derive from general peptide handling rather than a formal stability study.