Everything below concerns MC1R. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-07-15. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, which separates the target peptide from truncated or oxidised impurities. Mass spectrometry, most often coupled to liquid chromatography, confirms molecular mass and detects substitutions that chromatography alone may miss. Amino acid analysis and peptide mapping supply additional structural evidence, while nuclear magnetic resonance is reserved for full structural confirmation. Laboratories that examine samples sold online report wide variation in actual content, with some vials containing little or none of the labelled material.
Melanotan-2 appears on the World Anti-Doping Agency prohibited list within the peptide hormone class, and several national regulators treat it as an unapproved prescription substance. Some countries restrict importation or sale for personal use. Because the compound is widely traded as a research chemical, the practical legal picture differs between jurisdictions and shifts over time. Human safety data covering long periods are limited, and whether repeated pigmentation changes carry any lasting risk to melanocytes remains an open question.
| 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 |
Regulatory treatment varies between countries. Several national medicines agencies have classified the peptide as unapproved, and customs authorities in some jurisdictions seize shipments on that basis. A few jurisdictions channel supply through prescription-only frameworks that do not list the substance by name. Because the material circulates mainly through online vendors, composition and purity are rarely verified before sale. Surveys of unapproved peptide products have reported labels that did not match measured content in a substantial fraction of samples.
Melanotan II is a synthetic cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone, a naturally occurring peptide involved in pigmentation signalling. Its structure substitutes a lactam bridge between side chains to increase stability relative to the native hormone. The compound is also known by the shorthand MT-II and by several non-proprietary synonyms used in research catalogues. It is not an approved therapeutic product in any major jurisdiction; material sold under this name is typically offered as a laboratory reagent rather than as a medicine.
Activity is attributed to agonism at melanocortin receptors, particularly MC1R and MC4R. Activation of MC1R on melanocytes increases melanin synthesis, which underlies the reported tanning effect. MC4R engagement in the central nervous system is linked to appetite suppression and to effects on sexual arousal reported in early clinical studies. Those studies were small and were not designed to establish efficacy or long-term safety. Receptor selectivity among the melanocortin subtypes is not absolute, which complicates attribution of any effect to a single pathway.
Solid peptide kept dry at minus twenty degrees Celsius, shielded from light and moisture, is generally considered stable for extended periods. Solutions are divided into single-use aliquots and held at minus twenty or minus eighty degrees Celsius, because repeated freeze-thaw cycles promote aggregation and loss of material to container surfaces. Hydrolysis of the backbone and oxidation of tryptophan are the principal degradation routes in aqueous solution, and both accelerate at ambient temperature. Hygroscopic uptake after a vial is opened can also shift the actual mass weighed, which affects any concentration calculated from it.
Routine characterisation relies on reversed-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres, using a C18 column and a water-acetonitrile gradient containing trifluoroacetic acid. Electrospray ionisation mass spectrometry confirms the expected molecular mass and can reveal truncated or oxidised by-products that co-elute poorly. Sequence and stereochemistry require additional work, such as peptide mapping or amino acid analysis, because a chromatographic purity figure alone does not distinguish a diastereomer from the target peptide. Independent testing of research-grade material frequently shows measured content below the stated label, so a certificate of analysis is best read together with the method that produced it.
==== COVID-19 ==== Dogs have been trained to sniff SARS CoV-2-related VOCs since the outbreak of COVID-19 pandemic. Their overall success rates of detection were similar to or higher than reverse transcription polymerase chain reaction (RT-PCR) and antigen testing procedures. Grandjean et al. trained the dogs to sit in front of samples from COVID-19 positive patients. The success rate of distinguishing the sweat odor of individuals with COVID-19 from individuals without COVID-19 was between 83% and 100%. In principle, the dogs could be used to screen individuals with various stages of COVID-19 infections (including asymptotic, presymptomatic individuals with mild to severe symptoms) in different settings such as schools, transportation centers like airports, hospitals, and public gatherings. An advantage of using trained dogs compared to primates or cats to detect COVID-19 is that dogs are animal species with a low risk of binding between ACE2 receptor and SARS CoV-2, making them less likely to be transmitters. To further minimize the risk of transmission to dogs, sniffing sweat (which has low transmission property) is deemed the ideal mechanism for dogs to detect COVID-19. Other advantages of using dogs for screening COVID-19 over the current RT-PCR method are lower cost, decreased intrusiveness to the subjects, and no delay in reporting the results.
== Further reading == Allen, Joe (April 7, 2020). The Package King: A Rank-and-File History of UPS. Chicago, Illinois: Haymarket Books. ISBN 9781642592177. Brewster, Mike and Frederick Dalzell. Driving Change: The UPS Approach to Business (2007) excerpt and text search Thomas L. Friedman, "Insourcing," in The World Is Flat: A Brief History of the Twenty-First Century, New York: Farrar, Straus and Giroux, updated and expanded, 2006, pp. 167–176. Minchin, Timothy J. "Shutting Down 'Big Brown': Reassessing the 1997 UPS Strike and the Fate of American Labor," Labor History, 53 (Nov. 2012), 541–60. Niemann, Greg. Big Brown: The Untold Story of UPS. New York: John Wiley & Sons, 2007.
== Preservation of other products == Water-based home and personal care products use broad-spectrum preservatives, such as isothiazolinones and formaldehyde releasers, which may cause sensitization, leading to allergic skin.
The plan was that Johannesburg would revolt and seize the Boer armoury in Pretoria. Jameson and his force would dash across the border to Johannesburg to "restore order" and with control of Johannesburg would control the gold fields. However, while Jameson waited for the insurrection to begin, differences arose within the Reform Committee and between Johannesburg Uitlander reformers regarding the form of government to be adopted after the coup. At a point, certain reformers contacted Jameson to inform him of the difficulties and advised him to stand down. Jameson, with 600 restless men and other pressures, became frustrated by the delays and, believing that he could spur the reluctant Johannesburg reformers to act, decided to go ahead. He sent a telegram on 28 December 1895 to Rhodes warning him of his intentions – "Unless I hear definitely to the contrary, shall leave to-morrow evening" – and on the very next day sent a further message, "Shall leave to-night for the Transvaal". However, the transmission of the first telegram was delayed, so that both arrived at the same time on the morning of 29 December, and by then Jameson's men had cut the telegraph wires and there was no way of recalling him. On 29 December 1895, Jameson's armed column crossed into the Transvaal and headed for Johannesburg. They hoped that this would be a three-day dash to Johannesburg before the Boer commandos could mobilise, and would trigger an uprising by the Uitlanders.
Sources: en.wikipedia.org
Owing to its distance from open sea and its position on the southeastern portion of the European continent, Romania has a climate that is continental, with four distinct seasons. The average annual temperature is 11 °C (52 °F) in the south and 8 °C (46 °F) in the north. In summer, average maximum temperatures in Bucharest rise to 28 °C (82 °F), and temperatures over 35 °C (95 °F) are fairly common in the lower-lying areas of the country. In winter, the average maximum temperature is below 2 °C (36 °F). Precipitation is average, with over 750 mm (30 in) per year only on the highest western mountains, while around Bucharest it drops to approximately 570 mm (22 in). There are some regional differences: in western sections, such as Banat, the climate is milder and has some Mediterranean influences; the eastern part of the country has a more pronounced continental climate. In Dobruja, the Black Sea also exerts an influence over the region's climate.
According to the constitution of Greece, higher education institutions (HEI) include universities, technical universities, and specialist institutions. HEI undergraduate programs are government-funded and do not charge tuition. A quarter of HEI postgraduate programs are tuition-free. After individual assessments, thirty percent of Greek students are entitled to attend any of the statutory postgraduate programs without tuition fees. Founded as a national institution in 1926, the Academy of Athens is the highest research establishment in Greece. Private higher education institutions could not operate in Greece and were not recognized as degree-awarding bodies by the Greek government until the law 5094/2024 was passed in 2024, permitting the establishment and operation of private Higher Education Institutions (HEIs). Such HEIs are yet to be accredited and established.
Intracellular Hbs. These globins reside inside a cell, much like the vertebrate Hb. Multi-subunit Hbs. These globins form complexes and work outside a cell. Multi-domain, multisubunit Hbs. These globins form complexes, work outside a cell, and have multiple globin domains per peptide chain. Erythrocruorin and chlorocruorin belong to the multisubunit Hbs, specifically of the 12-dodecamer type.
== Ownership == The SCIRP website is operated by Wuhan Erwan Culture Communication Co., Ltd. Wuhan Erwan Culture Communication Co., Ltd is primarily owned by Wuhan Grand Technology Service Co., Ltd. Engineering Information Institute, a member or source content provider of SCIRP, is also owned by Wuhan Erwan Culture Communication Co., Ltd.
=== Carlton Football Club === In 2018, Stanton joined the Carlton Football Club in an assistant coaching role as a development coach. He also plays for the Banyule Bears in the Northern Football League who were eliminated in their preliminary final after they were beaten by the Lower Plenty Jabba's. In August 2021, at the end of the 2021 season, Stanton was sacked by Carlton as an assistant coach, due to a clean-out at the club, after an extensive review of the club's football operations.
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 lyophilised solid is best kept cold, dry and dark, typically at minus twenty degrees Celsius. Moisture and repeated warming cycles are the main causes of degradation. Solutions prepared from the powder are less stable and are normally used quickly.