If you have been reading about melanocortin receptor and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Updated 2025-12-14. Numbers and descriptions here follow the published literature rather than marketing material.
Research interest has centred on photoprotection and pigmentation, with a smaller body of work on appetite and sexual function. Published human data remain limited to small, frequently uncontrolled studies, and the compound has never received marketing approval from a national medicines regulator. Most laboratory work treats it as a pharmacological tool for probing melanocortin signalling in cell culture or animal models. Whether pigmentation changes observed in people translate into measurable protection against ultraviolet-induced DNA damage remains an open question.
Melanotan-2 is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone, the naturally occurring peptide involved in pigmentation signalling. Its sequence is conventionally written as Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, with a lactam bridge joining the aspartate side chain to the lysine side chain. The empirical formula is C50H69N15O9 and the monoisotopic mass lies near 1023.5 daltons. N-terminal acetylation and the D-configured phenylalanine both increase resistance to enzymatic breakdown compared with the parent hormone.
Melanocortin receptors comprise five subtypes with distinct tissue distributions and functions. Melanotan-2 is described in the literature as a non-selective agonist that engages several of these subtypes, including MC1R, MC3R, MC4R, and MC5R. MC1R is the subtype most directly linked to melanin production in skin cells. Because the compound is not subtype-selective, its observed effects in experimental settings are generally attributed to activity across multiple receptor pathways rather than to a single target.
Melanotan-2 is a synthetic linear peptide built from seven amino acids arranged in a short chain. Its sequence is commonly written as Ac-Nle-Asp-His-D-Phe-Arg-Trp-Lys-NH2, which includes a modified N-terminus and an amidated C-terminus. The molecule belongs to the melanocortin family and acts as a receptor agonist. Structural features such as the D-phenylalanine residue and the Nle substitution are associated with increased stability against enzymatic degradation relative to the natural parent peptide.
| Property | Value | Notes |
|---|---|---|
| Common synonyms | Melanotan II; MT-II; N-acetyl-norleucyl-cyclo[Asp-His-D-Phe-Arg-Trp-Lys] amide | Naming follows peptide convention; the numeral distinguishes it from melanotan-1 |
| Molecular formula | C50H69N15O9 | Includes the lactam bridge; no counter-ion assumed |
| Monoisotopic mass | 1023.53 Da | Free base; salts and counter-ions shift the observed value |
| Appearance | White to off-white lyophilised powder | Batch-to-batch colour variation is not itself proof of impurity |
| Typical analytical method | RP-HPLC purity determination with ESI-MS identity confirmation | Retention time alone does not establish sequence identity |
Receptor studies place melanotan-2 among non-selective melanocortin agonists, binding MC1R, MC3R, MC4R and MC5R rather than a single subtype. Activation of MC1R on cutaneous melanocytes raises tyrosinase activity and shifts pigment synthesis toward eumelanin, which is darker and more photostable than pheomelanin. Central receptors, particularly MC4R, are associated with appetite suppression and with reported effects on sexual function. Because subtype selectivity is low, the same molecule engages pigment, metabolic and vascular pathways at once, and this breadth is a common explanation offered for the range of adverse events described in user reports.
No regulatory authority has approved melanotan-2 for human use, and several countries classify it as a prescription-only or controlled substance, which restricts lawful supply. Material sold online is generally labelled as a research chemical and is not required to meet pharmaceutical standards of identity or purity. Published human data consist mainly of small uncontrolled studies, case reports and adverse-event notifications, so the evidence base is descriptive rather than confirmatory. Whether repeated melanocyte stimulation alters long-term naevus behaviour remains an open question that no completed trial has resolved.
Melanotan-2 is a synthetic cyclic heptapeptide designed as a structural analogue of alpha-melanocyte-stimulating hormone, the endogenous tridecapeptide that regulates pigment production. Two modifications distinguish it from the natural hormone: norleucine replaces methionine at the N-terminus, which limits oxidation, and a D-phenylalanine substitution raises receptor affinity. The ring is closed through an aspartate-lysine lactam bridge, giving the molecule a constrained conformation. The free base has a molecular mass near 1024 daltons, and commercial material is usually supplied as an acetate salt. It appears in the literature as a research peptide rather than an approved therapeutic agent.
Technology companies have built electricity and artificial intelligence infrastructure to facilitate the AI boom of the 2020s. A 2025 report from the consulting firm McKinsey & Company estimated that by 2030, $2.7 trillion would be invested into AI infrastructure and data centres in the US, surpassing World War II's Manhattan Project every month. In January 2024, the International Energy Agency (IEA) released Electricity 2024, Analysis and Forecast to 2026. This is the first IEA report to make projections for data centres and power consumption by AI and cryptocurrency. The report states that power demand for these uses might double by 2026, with the additional power consumption equaling that of Japan. Power consumption by AI is responsible for an increase in fossil fuel use, and has delayed closings of obsolete, carbon-emitting coal energy facilities. A ChatGPT search involves 10 times as much electrical energy as a Google search. A 2024 Goldman Sachs research paper, AI Data Centers and the Coming US Power Demand Surge, found "US power demand (is) likely to experience growth not seen in a generation...." and forecasts that, by 2030, US data centres will consume 8% of US power, as opposed to 3% in 2022, presaging growth for the electrical power generation industry by a variety of means. Data centres' need for more and more electrical power is such that they might max out the electrical grid. The Big Tech companies counter that AI can be used to maximise the utilisation of the grid by all.
A study on the relationship between morphology and ecology of extant and extinct members of Feliformia is published by Barrett & Hopkins (2026), who identify three adaptive zones within the studied group, and find that hypercarnivorous feliforms, unlike members of the group with broader diets, can be reliably identified on the basis of the study of their dental morphology. Kargopoulos et al. (2026) revise the composition of the ictitheriine hyaenid assemblage from the Miocene strata from the Venta del Moro (Spain), reporting possible evidence of presence of a second species in addition to Hyaenictitherium wongii. Kargopoulos et al. (2026) identify bite punctures in skulls of Adcrocuta eximia from the Miocene strata from the Torrentet dels Traginers site and Chasmaporthetes lunensis from the Pleistocene strata from the La Puebla de Valverde site (Spain), interpreted as possible evidence of intraspecific aggression. A study on Pliocene coprolites from the Odesa catacombs (Ukraine), providing evidence of extensive bone and hair consumption by members of the genus Pliocrocuta interpreted as indicative of scavenging as primary feeding strategy, is published by Brachaniec et al. (2026). Evidence of morphological changes in the skull of Pachycrocuta brevirostris from the Pleistocene strata from the Taurida Cave (Crimea) during its ontogeny is presented by Lavrov et al. (2026). Evidence of increased adaptation of postcanine teeth of Pachycrocuta brevirostris to hypercarnivory and bone-cracking throughout the evolutionary history of the species is presented by Khantemirov et al.
== Life and work == Emanuel Gil-Av was born 1916 in Pensa of Tzarist Russia. After the death of his father, a physician, the family moved first to Central Europe and in 1928 to Tel-Aviv, Israel, where Gil-Av attended High School. Gil-Av studied petroleum chemistry at the University of Strasbourg. In 1940 he escaped the German occupation to England where he worked at first in the chemical laboratory of Chaim Weizmann, followed by the Petrochemical Ltd. in Manchester. After World War II, he moved to Palestine and he joined the Daniel Sieff Institute in Rehovot which was later on to become the Weizmann Institute of Science. In 1951 he earned his PhD under the supervision of Ernst David Bergmann. In his study of oil shale deposits, Gil-Av developed complex-forming stationary phases employing silver(I) ions for selective olefin separations by gas chromatography (GC). In co-operation with the centre of peptide chemistry at the Weizmann Institute of Science, he developed methods of the gas-chromatographic resolution of racemic α-amino acids. By coating a glass capillary column with the chiral stationary phase (CSP) N-trifluoroacetyl-L-isoleucine lauryl ester, Gil-Av et al. carried out in 1966 the first gas-chromatographic enantioseparation of racemic amino acids as N-trifluoroacetyl-O-alkyl derivatives. Many racemic compounds, amenable for enantioselective interaction via hydrogen bonding with the CSP, could be analytically enantioseparated by GC.
=== Brand collaborations === American fashion brand Denim Tears would be the first brand to collaborate with Clipse, unveiling a Let God Sort Em Out-branded T-shirt in June 2024, a whole year before the album's eventual release; this was in celebration of the brand's fifth anniversary. Further brand collaborations remained unknown until the release of "So Be It" on June 18, 2025, where Clipse would unveil an alternate album package and merchandise line, designed by Japanese artist Verdy. Williams's Billionaire Boys Club line would announce an exclusive black T-shirt on June 21. The company made the T-shirt available at their flagship stores from that date forward, with the shirt releasing online on July 11. Pusha T would begin teasing Clipse-branded Adidas Samba shoes on July 7; they were given an early-access release on July 14. A Carhartt collaboration was announced the following day; it was released alongside the album on July 11, featuring jackets, graphic T-shirts, a hoodie and sweatshirt. Another alternate album package, designed by American artist Josh Sperling, was announced on July 15.
Carlos Outeiral, CASP14: what Google DeepMind's AlphaFold 2 really achieved, and what it means for protein folding, biology and bioinformatics, Oxford Protein Informatics Group. (3 December) Mohammed AlQuraishi, AlphaFold2 @ CASP14: "It feels like one's child has left home." (blog), 8 December 2020 Mohammed AlQuraishi, The AlphaFold2 Method Paper: A Fount of Good Ideas (blog), 25 July 2021 AlphaFold-3 web server AlphaFold v2.1 code and links to model on GitHub Open access to protein structure predictions for the human proteome and 20 other key organisms at European Bioinformatics Institute (AlphaFold Protein Structure Database) CASP 14 website AlphaFold: The making of a scientific breakthrough, DeepMind, via YouTube. ColabFold, version for homooligomeric prediction and complexes
Sources: en.wikipedia.org
It is a cyclin dependent kinase containing the catalytic subunit, Cdk9, and a regulatory subunit, cyclin T in Drosophila. In humans there are multiple forms of P-TEFb which contain Cdk9 and one of several cyclin subunits, cyclin T1, T2, and K. P-TEFb associates with other factors including the bromodomain protein BRD4, and is found associated with a large complex of proteins called the super elongation complex. Importantly, for the AIDS virus, HIV, P-TEFb is targeted by the HIV Tat protein which bypasses normal cellular P-TEFb control and directly brings P-TEFb to the promoter proximal paused polymerase in the HIV genome.
== Further reading == Fetter, Steve; Cheng, E. T.; Mann, F. M. (1990). "Long-term radioactive waste from fusion reactors: Part II". Fusion Engineering and Design. 13 (2): 239–246. CiteSeerX 10.1.1.465.5945. doi:10.1016/0920-3796(90)90104-E. ISSN 0920-3796. {{cite journal}}: Cite uses deprecated parameter |citeseerx= (help) Holland, Jason P.; Sheh, Yiauchung; Lewis, Jason S. (2009). "Standardized methods for the production of high specific-activity zirconium-89". Nuclear Medicine and Biology. 36 (7): 729–739. doi:10.1016/j.nucmedbio.2009.05.007. ISSN 0969-8051. PMC 2827875. PMID 19720285. McCarthy, Deborah W.; Shefer, Ruth E.; Klinkowstein, Robert E.; Bass, Laura A.; Margeneau, William H.; Cutler, Cathy S.; Anderson, Carolyn J.; Welch, Michael J. (1997). "Efficient production of high specific activity 64Cu using a biomedical cyclotron". Nuclear Medicine and Biology. 24 (1): 35–43. doi:10.1016/S0969-8051(96)00157-6. ISSN 0969-8051. PMID 9080473.
== Adverse effects == Adverse effects in studies that were significantly more common under ertugliflozin than under placebo included mycosis of the genitals in both men and women, vaginal itch, increased urination, thirst, hypoglycaemia (low blood sugar), and weight loss under the higher dosing scheme. A rare but life-threatening side effect of gliflozins is ketoacidosis; it occurred in three patients (0.1%) in ertugliflozin studies. To lessen the risk of developing ketoacidosis (a serious condition in which the body produces high levels of blood acids called ketones) after surgery, the FDA has approved changes to the prescribing information for SGLT2 inhibitor diabetes medicines to recommend they be stopped temporarily before scheduled surgery. Symptoms of ketoacidosis include nausea, vomiting, abdominal pain, tiredness, and trouble breathing.
=== 2009 === In February 2009, the International Institute for Strategic Studies published an annual report, Military Balance 2009. The report said that Russian forces were well-prepared for the August war and the Russian military operation was strategically well-planned. In 2009, Martin Malek, a researcher at the Institute for Peace Support and Conflict Management of the National Defense Academy in Vienna, noted that in September 2008, the Valdai Discussion Club was told by Vladimir Putin about his August 8 meeting with Chinese officials in Beijing and discussion of the recognition of Abkhazia and South Ossetia; Malek concluded that 8 August 2008 was the latest date when the recognition of Abkhazia and South Ossetia was considered or "possibly already decided". Malek concluded that due to the anti-American bias of the western Europeans and mass dislike of George W. Bush, the western media was keen to put the blame for the war on the pro-American Georgian government. In May 2009, Kaarel Kaas wrote an article for International Centre for Defense Studies, where he noted that this war was the first time since the fall of the Soviet Union that the Russian military had been used against an independent state, demonstrating Russia's willingness to use military force to attain its political objectives. Kaas wrote, "The military operation was only one phase in a longer-term anti-Georgian campaign.
Sources: en.wikipedia.org
Daisy was the most famous campaign commercial of the Cold War. Aired only once, on 7 September 1964, it was a factor in Lyndon B. Johnson's defeat of Barry Goldwater in the 1964 presidential election. The contents of the commercial were controversial, and their emotional impact was searing. The commercial opens with a very young girl standing in a meadow with chirping birds, slowly counting the petals of a daisy as she picks them one by one. Her sweet innocence, along with mistakes in her counting, endear her to the viewer. When she reaches "9", an ominous-sounding male voice is suddenly heard intoning the countdown of a rocket launch. As the girl's eyes turn toward something she sees in the sky, the camera zooms in until one of her pupils fills the screen, blacking it out. The countdown reaches zero, and the blackness is instantly replaced by a simultaneous bright flash and thunderous sound which is then followed by footage of a nuclear explosion, an explosion similar in appearance to the near surface burst Trinity test of 1945, followed by another cut to footage of a billowing mushroom cloud. As the fireball ascends, an edit cut is made, this time to a close-up section of incandescence in the mushroom cloud, over which a voiceover from Johnson is played, which states emphatically, "These are the stakes! To make a world in which all of God's children can live, or to go into the dark. We must either love each other, or we must die." Another voiceover then says, "Vote for President Johnson on November 3.
On October 31, a federal judge in Rhode Island cited the Administrative Procedure Act and temporarily ordered the Trump administration to continue SNAP funding. A second federal judge in Boston said the Trump administration's plan to stop SNAP funding during the shutdown was against the law, but did not order payments to resume. On November 7, Justice Ketanji Brown Jackson temporarily froze the lower court order requiring full payment of SNAP. ABC News stated, "at least nine states had already begun issuing SNAP benefits under the direction of the federal agency that operates SNAP," reportedly including California, Wisconsin, Kansas, Pennsylvania, New York, New Jersey, and Vermont. In early November, Trump called for ending the Senate's rule and tradition of the filibuster. On November 6, some Republican senators talked about making a "clean" Continuing Resolution one of the exceptions to the filibuster rule, but it's estimated that this change is unlikely. On November 9, the Senate achieved a 60-vote compromise of a "mini-bus" which will fund certain departments through next September and the rest of government through January 30. SNAP would be funded through September 2026. Senate Republicans agreed to have a vote on the Obamacare funding by the 2nd week of December. Eight Democrats voted with Republicans to end the shutdown. On November 12, the House passed the bill, 222 to 209. Trump then signed it into law.
=== Nonsurgical === Prevention of movement between the layers allows the tentative initial bond of fibrin to be reinforced by wound healing with a thin, strong, layer of scar. Avoiding certain positions for certain surgeries may have an effect. (In abdominoplasty, sitting upright with the knees bent and hips flexed will cause pressure across the lower abdomen and a tendency to seroma formation. The patient is best to stand or at least be semirecumbent). External pressure may help in immobilization, but also is thought to reduce the tendency of the fluid to leak out of vessels by increasing the backpressure on those fluid sources. Following breast augmentation or double mastectomy, binding the chest may be recommended for several weeks to minimize the risk of seromas.
It also introduced new menu items including a turkey burger, tater tots and a "triple double", although the latter prompted a copyright infringement lawsuit from In-n-Out Burger, as well as a class-action lawsuit for false advertising. The restaurant faced difficulties in continuing to grow, in part as shoppers began to shift away from shopping in traditional retail centers where its restaurants were concentrated. At the same time, larger restaurant chains increased their efforts to grow sales and brought on higher-quality menu items to compete with Smashburger and restaurants like it. Subsequently, Smashburger saw its overall same-store sales decline as a number of other local "better burger" concepts grew. Crane left as CEO in April 2016, and was replaced by Mike Nolan, but he resigned nine months later and Ryan took over the role. The restaurant thus condensed its expansion strategy to focus on existing markets and began mentorship programs to develop leadership talent from within its ranks of workers. It also bought back some franchise restaurants in several major markets. Smashburger competitors like Shake Shack and Five Guys experienced many of these difficulties, as well. In 2016, Smashburger was estimated to have $338.3 million in sales. On 13 February 2018, Jollibee increased its ownership stake to 85 percent of Smashburger in another $100 million deal. In making the acquisition, the companies said the move would allow Smashburger to further expand its presence in southeast Asia.
=== Physical === Data from the NCES showed that in the academic year 2018–19, 15% of students receiving special education under the Individuals with Disabilities Education Act was suffering from "other health impairments"—such as asthma, diabetes, epilepsy, heart problems, hemophilia, lead poisoning, leukemia, nephritis, rheumatic fever, sickle cell anemia, and tuberculosis. The American Optometric Association sounded the alarm on a link between the regular use of handheld electronic devices and eyestrain. Research by the Mayo Clinic in Minnesota found food allergies are becoming increasingly common since the early 2000s. Today, one in twelve American children has a food allergy, with peanut allergy being the most prevalent type. Nut allergies, in general, have quadrupled and shellfish allergies have increased 40% between 2004 and 2019. In all, about 36% of American children have some kind of allergy. One possible explanation, supported by the National Institute of Allergy and Infectious Diseases, is that parents keep their children "too clean for their own good." According to this "hygiene hypothesis," exposure to allergens give the infant's immune system some exercise, making it less likely to overreact. Evidence for this includes the fact that children living on a farm are consistently less likely to be allergic than their counterparts who are raised in the city, and that children born in a developed country to parents who immigrated from developing nations are more likely to be allergic than their parents are.
Sources: en.wikipedia.org
It is a synthetic cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone, containing seven amino acids with a lactam ring and a D-configured phenylalanine residue. It is supplied as a lyophilised powder for laboratory research.
The natural hormone is a linear tridecapeptide that is rapidly degraded in circulation. Melanotan-2 is shortened, cyclised, N-terminally acetylated, and carries a D-amino acid substitution, all of which slow enzymatic breakdown.
No national medicines regulator has approved melanotan-2 for therapeutic or cosmetic use. In several jurisdictions it is treated as an unapproved prescription medicine, and its legal classification differs from country to country.
No. Melanotan-2 is manufactured synthetically. The naturally occurring peptide in the same family is alpha-melanocyte-stimulating hormone, which the body produces as part of normal endocrine and neural signalling.