The short version of melanocortin receptor fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-01-24 and is reviewed periodically as new material appears.
Melanotan II holds no marketing authorisation from the Food and Drug Administration, the European Medicines Agency, the UK Medicines and Healthcare products Regulatory Agency or Australia's Therapeutic Goods Administration. Products sold under that name are treated as unapproved new drugs, and their sale or import is prohibited in several jurisdictions. Other countries classify the peptide as a prescription-only medicine or place it among controlled substances, so the legal position changes with the destination market. No pharmacopoeial monograph supplies an official specification, because the material is not a licensed pharmaceutical. Consequently, products offered online are not manufactured to a shared public standard.
The peer-reviewed record is dominated by small early-phase studies, case reports and pharmacovigilance summaries rather than large randomised trials. Papers typically examine tanning response, receptor selectivity or patterns of reported adverse events. Many note that participants obtained the peptide outside a clinical setting, which limits verification of composition and administered amount. Reported events vary widely, and causality is frequently unclear because the identity and purity of self-sourced material are unknown. Open questions include whether repeated melanocortin receptor stimulation produces cumulative effects, and how often label claims match actual content.
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.
Early published reports described melanotan-2 as a tanning agent without sun protection, which means darkening is not the same as protection against ultraviolet radiation. Later studies explored the peptide in erectile dysfunction, hemorrhagic shock, and some skin conditions. No regulator in the United States or Europe has approved it for clinical use. Many products labelled melanotan-2 are sold without approval and their identity and purity are unverified. Its long-term safety in humans remains an open question.
| Property | Value | Notes |
|---|---|---|
| Regulatory status | Unapproved in the US, EU and Australia | Sale and import restricted; no licensed product |
| Typical test matrices | Urine, serum, seized powder | Urinary detection window is short |
| Primary identification method | LC-MS/MS against a reference standard | High-resolution mass used for confirmation |
| Data sources in the literature | Small trials, case reports, pharmacovigilance | No registrational trial dataset exists |
| Common marketing names | Melanotan 2, MT-II, MT-2 | Label content may not match declared peptide |
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.
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.
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.
Melanotan-2 is handled in the laboratory as a lyophilised powder that dissolves readily in water, dimethyl sulfoxide and dimethylformamide, with limited solubility in ethanol. Stock solutions prepared in an organic solvent often precipitate when diluted into aqueous buffer, so gradual dilution with mixing is standard practice. The peptide carries a tryptophan residue and a histidine residue, both sensitive to oxidation and to alkaline conditions. Working solutions are therefore kept near neutral to slightly acidic pH, protected from light, and consumed within the same working session whenever that is practical.
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.
Pharmacologically, melanotan-2 behaves as a non-selective agonist across the melanocortin receptor family. Binding at MC1R on dermal melanocytes promotes eumelanin synthesis, which underlies the tanning response described in early human work. Activity at the centrally expressed MC4R receptor is associated with reported effects on appetite and erectile function. Because the peptide does not discriminate strongly among receptor subtypes, attributing any single observed effect to one receptor pathway is generally not possible without selective antagonists or receptor knockout models.
Kimon Georgiev became prime minister on 19 May 1934, after the coup d'état. He served as Minister of Foreign Affairs and Religious Affairs (19-23 May 1934) and Minister of Justice (23 May 1934 – 22 January 1935) and temporarily served as Minister of War on 19 May 1934. Kimon Georgiev led the new Cabinet, which was primarily made up of Zveno and Military League representatives. Although they denounced the coup, the other bourgeois parties and the non-fascist bourgeois parties accepted it. The BCP called it a fascist coup, but they were unable to put up a united front to fight it due to mistakes in secretarian doctrine. The coup's perpetrators said in their manifesto that a "national supra-party power" would be established. They abolished the Parliament, dissolved the IMRO, and restructured the governmental apparatus on a fascist basis.
== Specific examples == Using the bacterial one-hybrid system, one study has characterized 35 members of the Drosophila melanogaster segmentation network which includes representative members of all the major classes of DNA-binding domain proteins. Implications for medical research are evident from another study that used the B1H system to identify the DNA-binding specificity of a transcriptional regulator for a gene in Mycobacterium tuberculosis. The B1H system has also been used to identify an important turnover element in Escherichia coli.
=== Reverse osmosis and desalination === In reverse osmosis (RO) and desalination plants, antiscalants are vital for preventing scale formation on membrane surfaces. Scaling can severely impair the efficiency of these processes and lead to increased maintenance costs. Antiscalants help maintain optimal performance and prolong the lifespan of membranes. Scales form in the RO or desalination plants when the ionic product of sparingly dissolved salts in the concentrated flow equals or exceeds their solubility product. The extent and degree of scaling phenomena are determined not only by the supersaturation conditions that occurred, but also by the precipitation kinetics.
Sources: en.wikipedia.org
This technique does not entail immobilization or labeling. Transient and weak interactions can be characterized. Relative to static light scattering, which is based upon the absolute intensity of scattered light, DLS is insensitive to background light from the walls of containing structures. This insensitivity permits DLS measurements from 1 μL volumes in 1536 well plates, and lowers sample requirements into the femtomole range. This technique is also suitable for screening of buffer components and/or small molecule inhibitors/effectors. Flow-induced dispersion analysis (FIDA), is a new capillary-based and immobilization-free technology used for characterization and quantification of biomolecular interaction and protein concentration under native conditions. The technique is based on measuring the change in apparent size (hydrodynamic radius) of a selective ligand when interacting with the analyte of interest. A FIDA assay works in complex solutions (e.g. plasma , serum, lysate), and provides information regarding analyte concentration, affinity constants, molecular size, binding kinetics, aggregation. A single assay is typically completed in minutes and only requires a sample consumption of a few μL. It can be used as a self-sufficient method, or in a workflow with SPR, to de-risk and speed up SPR assays. In terms of novel applications, it is used for de novo protein screening. In terms of traditional applications it is e.g. used for interaction studies across membrane proteins and antibodies.
This bonds creates strong hydrogen bonds and leads to a strong interlocking amongst the acyl chains 5) why the presence of cholesterol; a sterol compound, inhibits ethanol's ability to disrupt the membrane and 6) deriving the molecular-level mechanism of the entire process.
when she went to see her brother Rubén who was extradited in the US for drug trafficking. She was charged with engaging in transactions or dealings in properties with businesses blacklisted by the Treasury Department and providing financial support to the CJNG. She pleaded guilty on 12 March 2021, and on 11 June was sentenced to 21⁄2 years in prison. On 11 March 2020, the U.S. Drug Enforcement Administration (DEA) arrested 600 people and seized more than a ton and a half of narcotics. This is the DEA's largest-ever strike against CJNG. The number of arrests was revised to 750, with 250 arrests occurring in the United States. On 10 April 2020, Oseguera's Chicago area lieutenant Luis Alderate was arrested. Other high-level associates of Oseguera prosecuted in Chicago include Diego Pineda-Sanchez, sentenced to 15 years in prison for laundering money for him and other drug kingpins, and Carlos Perra-Pedroza, sentenced to 13 years in prison for similar charges. Alderate's brother Roberto Alderete was arrested in Kentucky in 2018 with two pounds of methamphetamine. On 11 April 2020, CJNG cell leader María del Carmen Albarrán was arrested in the Venustiano Carranza borough of Mexico City. In May 2020, it was reported that former CJNG security chief Enrique Alejandro Pizano, who was arrested in September 2015 died in a Jalisco prison on 13 May 2020 due to COVID-19. On 28 June 2020, it was reported that the number of CJNG members arrested for 26 June 2020 assassination attempt of the Mexican City Police Chief had grown to 19.
== External links == "Formylpeptide Receptors". IUPHAR Database of Receptors and Ion Channels. International Union of Basic and Clinical Pharmacology. Archived from the original on 2015-06-19. Retrieved 2007-11-02. Formyl+peptide+receptor at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
Sources: en.wikipedia.org
Both laser and conventional surgeries are performed to treat glaucoma. Surgery is the primary therapy for those with congenital glaucoma. Generally, these operations are a temporary solution, as there is not yet a cure for glaucoma.
Disulfur decafluoride is a chemical compound with the formula S2F10. It was discovered in 1934 by Denbigh and Whytlaw-Gray. Each sulfur atom of the S2F10 molecule is octahedral, and surrounded by five fluorine atoms and one sulfur atom. The two sulfur atoms are connected by a single bond. In the S2F10 molecule, the oxidation state of each sulfur atoms is +5, but their valency is 6 (they are hexavalent). It is a colorless liquid with a burnt match smell similar to sulfur dioxide.
=== Alienizers === Space Criminal Alienizers (宇宙犯罪者アリエナイザー, Uchū Hanzaisha Arienaizā) is an umbrella term that S.P.D. gives to aliens that commit various crimes on Earth and other planets. Unlike most monsters in the Super Sentai franchise, many of the Alienizers pilot giant robots called Kaijuki (怪重機, Kaijūki; "Monstrous Heavy Industrial Machines"), which are usually provided by Agent Abrella.
=== Extremism and hate === Concerns have been voiced regarding content relating to, and the promotion and spreading of, hate speech and far-right extremism, such as antisemitism, islamophobia, racism, and xenophobia. Some videos were shown to expressly promote Holocaust denial and told viewers to take up arms and fight in the name of white supremacy and the swastika. As TikTok has gained popularity among young children, and the popularity of extremist and hateful content is growing, calls for tighter restrictions on their flexible boundaries have been made. TikTok has since released tougher parental controls to filter out inappropriate content and to ensure they can provide sufficient protection and security. In October 2019, TikTok removed about two dozen accounts that were responsible for posting ISIL propaganda and execution videos on the app. In Malaysia, TikTok is used by some users to engage in hate speech against race and religion especially mentioning the 13 May incident after the 2022 election. TikTok responded by taking down videos with content that violated their community guidelines. In March 2023, The Jewish Chronicle reported that TikTok still hosted videos that promoted the neo-Nazi propaganda film Europa: The Last Battle, despite having been alerted to the issue four months prior. TikTok said it removed and would continue to remove the content and associated accounts and has blocked the search term as well.
=== Protein evolution and origins of life === In addition to structural bioinformatics, Ben-Tal has worked on protein evolution and the emergence of protein architectures and functions. His laboratory describes this research as addressing how novel protein structures and functions arise during molecular evolution. To trace the evolutionary history of proteins, Ben-Tal, Rachel Kolodny of University of Haifa and coworkers searched among large representative sets of proteins for segments that are similar in sequence (and often also in structure). They presented the results as a similarity network, using a methodology that they tailor-made for this study, showing that many proteins share smaller segments with each other. For example, they observed the same amino acid both within a short theme shared by many proteins and within a longer theme shared only by few. Next, they searched for themes that appear in different sequence and structural contexts within proteins, calling these bridging themes. They found many bridging themes, with an average length of about 40 residues. Interestingly, only about half of these also share a similar structure; the different environment may have induced a conformational change. Some of the bridging themes bind ligands, which attests to their functional importance. Another testimony to the evolutionary importance of these themes is the fact that some of the most ancient protein folds (e.g. Rossmann, P-loop, and TIM-barrel) were found to share them. The bridging themes may offer hints to the emergence of earliest protein families.
Sources: en.wikipedia.org
Regulatory treatment varies by country. In the United States, the European Union and Australia it is an unapproved drug and its sale is restricted, while some other jurisdictions list it as prescription-only or controlled. The applicable rules depend on the country of import.
Reversed-phase LC-MS/MS is the usual approach for both identification and quantitation. High-resolution mass spectrometry and peptide mapping serve as confirmatory methods. Immunoassays are rarely used alone because of cross-reactivity.
Published testing of seized and purchased samples frequently reports discrepancies between declared and measured peptide content. Counter-ion content and residual solvents add further variation. Independent analysis is the only way to confirm composition.
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.