The short version of prohibited list fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2025-08-18 and is reviewed periodically as new material appears.
Receptor binding at MC1R on melanocytes raises intracellular cyclic AMP and increases expression of tyrosinase and related enzymes. The downstream result is greater synthesis of eumelanin, the dark pigment, without ultraviolet exposure acting as the trigger. The compound is not selective, however, and also engages MC3R, MC4R and MC5R, which are expressed in the central nervous system and elsewhere. That lack of selectivity is the explanation usually offered for effects reported outside pigmentation, including appetite suppression and nausea. Selectivity remains a central theme in comparative studies of related peptides.
Human data remain limited and mostly short-term. Reports describe small trials and observational accounts rather than large controlled studies, so questions about dose-response relationships and long-term effects on melanocytes stay open. Whether repeated exposure alters naevus behaviour is not settled in the published record. Researchers also note that self-administered use outside clinical settings makes actual exposure difficult to quantify. Statements about efficacy and safety should therefore be read as preliminary rather than established.
Melanotan II is a synthetic cyclic heptapeptide that acts as an agonist at melanocortin receptors. It was designed as a structural analogue of alpha-melanocyte-stimulating hormone, the endogenous peptide involved in pigment production. The analogue carries a lactam bridge that constrains the ring and slows enzymatic breakdown relative to the native hormone. In research literature it appears under several abbreviations, and naming conventions are not fully standardized. Published descriptions usually place it within the broader melanocortin agonist family.
Identity testing for a cyclic peptide of this size usually relies on reversed-phase high-performance liquid chromatography coupled to mass spectrometry. The mass spectrum confirms molecular weight, while the chromatographic trace indicates the proportion of related impurities. Tandem mass spectrometry can provide sequence-level information when fragmentation data are compared against a reference standard. Nuclear magnetic resonance is sometimes used to confirm the lactam bridge, although it requires more material and greater operator expertise than routine chromatographic methods.
Lyophilised peptide powder is comparatively stable when kept dry, cold and protected from light. Once dissolved, the molecule is exposed to hydrolysis, oxidation and microbial growth, and degradation accelerates at higher temperatures and in alkaline solution. Repeated freeze-thaw cycles concentrate solutes and promote aggregation. Handling guidance for research peptides commonly clusters around freezer temperatures for powder and short refrigerated use for reconstituted solutions, with pH control and sterile technique applied throughout.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic cyclic heptapeptide | Melanocortin receptor agonist |
| Molecular formula | C50H69N15O9 | Neutral form, mass near 1024.2 g/mol |
| Primary targets | MC1R, MC3R, MC4R, MC5R | Binding is non-selective across subtypes |
| Related compounds | Alpha-MSH, melanotan I, afamelanotide | Structurally or functionally related peptides |
| Common abbreviations | MT-II, MT-2 | Naming in the literature is not uniform |
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.
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.
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.
Identification in laboratories relies on reversed-phase liquid chromatography coupled with tandem mass spectrometry, with product-ion spectra compared against a certified reference standard. High-resolution mass spectrometry supplies accurate mass confirmation, and peptide mapping after enzymatic digestion separates melanotan II from closely related analogues. Quantitation of seized material is complicated by unknown counter-ions and residual trifluoroacetate left from purification. Immunoassays raised against alpha-melanocyte-stimulating hormone can cross-react, so chromatographic confirmation is normally required. Urinary detection windows are short, and reported limits of detection differ substantially between laboratories.
Melanotan-2 is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone. Its sequence incorporates a lactam bridge that constrains the peptide into a ring, which increases resistance to enzymatic breakdown relative to the natural hormone. Researchers at the University of Arizona synthesised the compound in the late 1980s and early 1990s while studying pigmentation pathways. It has never received marketing approval from any national medicines regulator. In the scientific literature it is usually described as a laboratory research reagent rather than a therapeutic product.
The peptide acts as a non-selective agonist at melanocortin receptors, showing affinity for MC1R, MC3R, MC4R and MC5R. Activation of MC1R on melanocytes drives the conversion of tyrosine into melanin and shifts production toward the darker eumelanin form. MC4R signalling in the central nervous system is linked to appetite and energy balance, which helps explain why reduced food intake appeared in early human studies. Effects on MC4R and on vascular tone also account for the erectile responses recorded as unexpected findings in those same trials.
Melanotan-2 is frequently confused with afamelanotide, a linear analogue authorised in the European Union for erythropoietic protoporphyria. The two compounds differ in chain length, ring structure and receptor selectivity, so findings for one cannot be transferred directly to the other. Published controlled human data on melanotan-2 remain sparse, and much of what circulates online derives from small studies or unpublished reports. Questions about effect size, dose-response behaviour and long-term safety therefore remain unresolved.
Published research on the compound remains limited. Much of the human data comes from small, early-stage studies rather than large controlled trials, and several questions about effects and variability between individuals remain open. Investigators have examined receptor activity, pigment pathways, and related physiological responses in laboratory and animal models. Findings from those models do not automatically translate to human outcomes. Reviews frequently note the scarcity of rigorous clinical evidence and call for better-characterized study material.
Because the substance circulates mainly through informal markets, verification is a recurring theme in technical discussion. Independent analyses have found that labeled content and actual content can diverge, and that purity varies between samples. Analytical laboratories use reversed-phase chromatography to separate components and mass spectrometry to confirm identity. Isotope-labeled internal standards improve quantification in complex matrices. Such methods describe what a sample contains but say nothing about its sterility, lawful status, or suitability for any use. Open questions remain about how consistently testing is applied across the supply chain.
Regulatory treatment of this peptide varies by country. It holds no marketing authorization as a medicine in the United States, the European Union, or most other jurisdictions. Some countries classify products containing it as prescription-only or unlicensed medicines, which restricts lawful supply. Authorities have issued public notices warning that unregulated products may contain undeclared or incorrect ingredients. The molecule also appears on prohibited lists for competitive sport. These measures address supply oversight rather than any approved therapeutic role.
telomere A region of repetitive nucleotide sequences at each end of a linear chromosome which protects the end of the chromosome from deterioration and from fusion with other chromosomes. Since each round of replication results in the shortening of the chromosome, telomeres act as disposable buffers which are sacrificed to perpetual truncation instead of nearby genes; telomeres can also be lengthened by the enzyme telomerase.
Despite his triumph in Rome, he lost his opening round match at the French Open. During the grass court season, Zverev made another singles final and again faced Federer at the Halle Open, but could not defeat him this time. He and his brother also finished runner-up in the doubles event to Łukasz Kubot and Marcelo Melo. At Wimbledon, he achieved his best result at a major event to date, ultimately losing in the fourth round to the previous year's runner-up Milos Raonic in a tight five-set match. Back on hard courts, Zverev won his last two titles of the season in August. He won the Washington Open as well as a second consecutive Masters title at the Canadian Open, only dropping a single set at each tournament in each of his opening matches. Notably, he needed to save three match points in his first match in Canada against Richard Gasquet, including a 49 shot rally. He then defeated Roger Federer in the final to become the first player outside of the Big Four to win multiple Masters titles in the same season since David Nalbandian in 2007. Despite this success, he was upset in the second round of the US Open by fellow Next Gen player Borna Ćorić. At the end of the season, Zverev qualified for both the inaugural Next Generation Finals as one of the top seven 21-and-under players, and the ATP Finals as one of the top eight players in the world. He opted to skip the former event to focus on the latter. At the ATP Finals, Zverev was grouped with Roger Federer, Marin Čilić, and Jack Sock.
With the destruction of the Zaporizhian Sich, a number of Ukrainian-speaking Eastern Orthodox Zaporozhian Cossacks fled to the territory under the control of the Ottoman Empire. Together with Cossacks of Greater Russian origin, as well as the vast majority of Old Believers and other people from "Greater Russia" (Muscovy), they settled in the area of the Danube river, and founded a new Sich. Many Ukrainian peasants and adventurers later joined the Danubian Sich. While Ukrainian folklore remembers the Danubian Sich, other new siches of Loyal Zaporozhians on the Bug and Dniester rivers did not achieve such fame. Other Cossacks settled on the Tisa river in the Austrian Empire, also forming a new Sich. During the Cossack sojourn under Turkish rule, a new host was founded that numbered around 12,000 people by the end of 1778. Cossack settlement on the Russian border was approved by the Ottoman Empire after the Cossacks officially vowed to serve the sultan. Yet internal conflict, and the political maneuvering of the Russian Empire led to splits among the Cossacks. Some of the runaway Cossacks returned to Russia, where the Russian army used them to form new military bodies that also incorporated Greeks, Albanians and Crimean Tatars. After the Russo-Turkish war of 1787–1792, most of these Cossacks were absorbed into the Black Sea Cossack Host together with Loyal Zaporozhians. Most of the remaining Cossacks who had stayed in the Danube Delta returned to Russia in 1828. They settled in the area north of the Azov Sea, becoming known as the Azov Cossacks.
Sources: en.wikipedia.org
Pancreatic Ductal Adenocarcinoma (PDAC) is one of the most lethal cancers and has a 5-year survival rate of 13%. Pancreatic adenocarcinoma cells resemble pancreatic ductal cells. Both cell groups show tubule formation, cuboidal shape, and ductal markers. Additionally, acinar and endocrine cells have often been found in many of these cancers, demonstrating plasticity and the possibility that the initial target cells are pancreas progenitor cells. Moreover, human tumors usually go with lower-grade lesions that are called pancreatic intraepithelial neoplasias (PanINs) and are in ducts. Because these lesions are in ducts, this means that it is possible that the beginning target cells are ductal cells.
Mkhedrioni relied on illegal sources of income (targeting gasoline supplies) and exploited connections with Moscow's Georgian underworld. Mkhedrioni members were often accused of criminal activity, extorting "protection money" from businesses in areas which they effectively controlled, operating roadblocks where drivers would be "fined", smuggling drugs and committing robberies. By 1991, the Mkhedrioni was claimed to have had about 1,000 fighters and 10,000 associate members – considerably more than the official state National Guard. Despite Gamsakhurdia and Ioseliani sharing a broadly similar nationalist outlook, the two men fell out badly shortly after Gamsakhurdia came to power in November 1990. In February 1991, Ioseliani was imprisoned without trial, along with many of his supporters, and the Mkhedrioni was banned. In August 1991, just after the Soviet coup attempt, Gamsakhurdia sacked Tengiz Kitovani, the commander of Georgia's National Guard, and his Prime Minister Tengiz Sigua resigned around the same time. Kitovani soon formed an anti-Gamsakhurdia alliance with Sigua and the imprisoned Ioseliani. In December 1991, Kitovani's supporters released Ioseliani from jail and launched a violent coup d'état against the Gamsakhurdia government in alliance with the Mkhedrioni. Intense gun battles took place in the streets of Tbilisi between the rebels and "Zviadists" holed up in the state parliament building during December 1991 – January 1992, which ended with Gamsakhurdia fleeing to the breakaway Russian republic of Chechnya. At least 100 people were killed in the fighting.
Eucalyptus globulus subsp. bicostata (Maiden, Blakely & Simmonds) J.B.Kirkp. (formerly Eucalyptus bicostata), commonly known as Victorian blue gum or eurabbie, has sessile flower buds arranged in groups of three; Eucalyptus globulus Labill. subsp. globulus, commonly known as Tasmanian blue gum, has flower buds arranged singly in leaf axils; Eucalyptus globulus subsp. maidenii (F.Muell.) J.B.Kirkp. (formerly Eucalyptus maidenii), commonly known as Maiden's gum has flower buds arranged in groups of seven Eucalyptus globulus subsp. pseudoglobulus (Naudin) J.B.Kirkp. (formerly Eucalyptus globulus var. pseudoglobulus), commonly known as Victorian eurabbie has pedicellate flower buds arranged in groups of three.
Sources: en.wikipedia.org
Following four months Transport was absorbed into the new "monster ministry" of the Department for the Environment, under Heseltine's ally Peter Walker. Heseltine was still responsible for transport, but also for local government reform, covered in the Local Government Act 1972. Redcliffe-Maude's proposals for unitary councils (i.e. merging the two layers of county and borough/district councils) were abandoned. Many historic counties were abolished. Large Metropolitan counties were created around the big cities, but many smaller cities lost their county borough status. One such was Plymouth, the eastern suburbs of which lay in Heseltine's seat of Tavistock. Plymouth opinion was particularly angry that education was now to be run by Devon County Council in Exeter, 40 miles away. Heseltine declined to support a campaign by Plymouth MP Dame Joan Vickers to create a Tamarside Metropolitan county, and was rebuked by Sir Henry Studholme, his predecessor as MP for Tavistock, for declining to support (on the grounds that as minister he might have to adjudicate any dispute) Plymouth Council's attempt to buy more land near Sparkwell to develop light industry under its control.
=== Central === If the TSH level is normal or low and serum free T4 levels are low, this is suggestive of central hypothyroidism (not enough TSH or TRH secretion by the pituitary gland or hypothalamus, respectively). There may be other features of hypopituitarism, such as menstrual cycle abnormalities and adrenal insufficiency. There might also be symptoms of a pituitary mass such as headaches and vision changes. Central hypothyroidism should be investigated further to determine the underlying cause.
=== Jiffy === In computing, the jiffy is the duration of one tick of the system timer interrupt. Typically, this time is 0.01 seconds, though in some earlier systems (such as the Commodore 8-bit machines) the jiffy was defined as 1⁄60 of a second, roughly equal to the vertical refresh period (i.e. the field rate) on NTSC video hardware (and the period of AC electric power in North America).
=== High-resolution melting of the entire amplicon === High-resolution melting analysis is the simplest PCR-based method to understand. Basically, the same thermodynamic properties that allowed for the gel techniques to work apply here, and in real-time. A fluorimeter monitors the post-PCR denaturation of the entire dsDNA amplicon. You make primers specific to the site you want to amplify. You "paint" the amplicon with a double-strand specific dye, included in the PCR mix. The ds-specific dye integrates itself into the PCR product. In essence, the entire amplicon becomes a probe. This opens up new possibilities for discovery. Either you position the primers very close to either side of the SNP in question (small amplicon genotyping) or amplify a larger region (100–400bp in length) for scanning purposes. For simple genotyping of an SNP, it is easier to just make the amplicon small to minimize the chances you mistake one SNP for another. The melting temperature (Tm) of the entire amplicon is determined and most homozygotes are sufficiently different (in the better instruments) in Tm to genotype. Heterozygotes are even easier to differentiate because they have heteroduplexes generated (refer to the gel-based explanations) which broadens the melt transition and usually gives two discernible peaks. Amplicon melting using a fluorescently-labeled primer has been described, but is less practical than using ds-specific dyes due to the cost of the fluorogenic primer. Scanning of larger amplicons is based on the same principles as outlined above.
Sources: en.wikipedia.org
It is a synthetic cyclic heptapeptide and a non-selective melanocortin receptor agonist. Structurally it is modelled on alpha-melanocyte-stimulating hormone, a peptide that occurs naturally in the body.
Activation of MC1R increases pigment synthesis independently of ultraviolet exposure, which is the mechanism usually cited for darkening without sun exposure. Ultraviolet light still influences skin response through separate biological pathways.
Because the peptide binds several melanocortin receptor subtypes, its effects are not confined to pigmentation. This complicates interpretation of both intended and unintended outcomes reported in studies.
Mass spectrometry combined with liquid chromatography provides both molecular weight confirmation and a measure of related impurities. Tandem mass spectrometry adds sequence information. A purity percentage reported without a mass measurement does not confirm what the material is.