Everything below concerns LC-MS/MS. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2025-11-07. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
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 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.
| 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 |
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.
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.
The compound was developed in the late 1980s and 1990s by academic researchers investigating photoprotection. The rationale held that stimulating melanin production might reduce ultraviolet damage to skin and lower skin cancer risk. Early work examined receptor binding, pigment response, and short-term tolerability in small studies. That program did not produce an approved drug, and formal development stalled after early-phase trials. Whether induced pigmentation confers meaningful photoprotection remains an open question.
Outside regulated medicine, melanotan II circulates through online vendors as a research chemical, often marketed for tanning. Products sold this way vary widely in purity, concentration, and labeling accuracy, and independent testing has documented discrepancies. Published reports describe both pigment effects and adverse reactions, including nausea, flushing, and darkening of existing moles. Long-term safety data are sparse, and no large controlled trial has established a risk profile. Questions about cumulative effects on melanocytes remain unresolved in the literature.
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.
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.
Other services may include those of banks, cafés, childcare centers/creches, insurance (and other financial services), mobile phone sales, photo processing, video rentals, pharmacies, and filling stations. In the US, if the eatery in a supermarket is substantial enough, the facility may be called a "grocerant", a portmanteau of "grocery" and "restaurant". The traditional supermarket occupies a large amount of floor space, usually on a single level. It is usually situated near a residential area in order to be convenient to consumers. The basic appeal is the availability of a broad selection of goods under a single roof, at relatively low prices. Other advantages include ease of parking and frequently the convenience of shopping hours that extend into the evening or even 24 hours of the day. Supermarkets usually allocate large budgets to advertising, typically through newspapers and television. They also present elaborate in-shop displays of products. Supermarkets typically are chain stores, supplied by the distribution centers of their parent companies, thus increasing opportunities for economies of scale. Supermarkets usually offer products at relatively low prices by using their buying power to buy goods from manufacturers at lower prices than smaller stores can. They also minimize financing costs by paying for goods at least 30 days after receipt and some extract credit terms of 90 days or more from vendors. Certain products (typically staple foods such as bread, milk and sugar) are very occasionally sold as loss leaders so as to attract shoppers to their store.
Fish food should ideally provide the fish with fat (for energy) and amino acids (building blocks of proteins) and the fish food (whether flake or pellet) must be speedily digested in order to prevent buildup of intestinal gas, kidney failure and infections (such as swim bladder problems and dropsy) and to avoid aquarium pollution due to excessive ammonia. Aquatic diets for carnivores must contain vegetable matter such as spirulina.
As a result of protests by Akwesasne residents on their rights to cross the border unimpeded, as provided under the 1795 Jay Treaty, the Canada Border Services Agency closed its post on Cornwall Island, instead requiring travellers to proceed to the checkpoint in the city of Cornwall. As a consequence of the arrangement, residents of the island are required to clear border controls when proceeding North to the Ontario mainland, as well as when proceeding South to Akwesasne territory in New York, thereby constituting internal controls from both a Canadian and an Akwesasne perspective. Similarly, travelling between Canada and the Quebec portion of the Akwesasne nation requires driving through the state of New York, meaning individuals must clear American controls when leaving Quebec proper and Canadian border controls when entering Quebec proper. However, Canada does not impose border controls when entering the Quebec portion of the Akwesasne Nation. Nevertheless, for residents who assert a Haudenosaunee national identity distinct from Canadian or American citizenship, the intricate network of Canadian and American border controls is seen as a foreign-imposed system of internal border controls, similar to the Israeli checkpoints in Palestinian territory. The city of Hyder, Alaska, has also been subject to internal border controls since America chose to stop regulating arrivals in Hyder from British Columbia.
peptide map A characteristic fractionation pattern produced by a particular polypeptide or protein when it is subjected to partial hydrolysis in vitro and the resulting peptide chains are separated by chromatography and/or electrophoresis.
=== Addition to alkenes and alkynes === The Hg2+ center binds to alkenes, inducing the addition of hydroxide and alkoxide. For example, treatment of methyl acrylate with mercuric acetate in methanol gives an α-mercuri ester:
Sources: en.wikipedia.org
=== Orthologs === There were orthologs identified in most animals for which there were complete genome data. The most distant, yet still relevant, orthologs identified were invertebrates from phylum Cnidaria.
Many were reported to not be wearing masks. Soon after, they dispersed. On 11 March, the number of people hospitalized hit a new record in Porto Alegre, with 800 people diagnosed to have COVID-19, and 43 suspected of being infected, and 187 awaiting beds. Even with this, Melo defended his administration in an interview published that day, businesses generally being open, then reduced by the state's decision to essential sectors. Due to the large increases in the number of deaths in the city, there were lines at the public records offices to register deaths, during which there waits of up to five hours, including during the early hours of the morning. The number of burials also increased. In total, the quantity of funerals in the city in March of that year was triple of those in March the prior year. The demand for cremations increased 63% during the middle of March 2021 in comparison with the first three months of the year prior for one crematorium. In another there was a 230% increase in cremations in comparison with March the year prior. Such was the amount of beds occupied that the waiting list for beds had grown to be days long. The overcrowding hit 116% on 15 March, with 1,204 people hospitalized with only 1,036 vacant beds. The waiting list would become 1270 people. At Hospital de Pronto Socorro, ran by the city, the overcrowding of beds led to 1,075% capacity. Various hospitals closed their emergency rooms because of the overcrowding of the units, including two of the largest in the city, Santa Casa and Clínicas.
== History == Food technologists have long known that protein hydrolysis produces a meat bouillon-like odor and taste. Hydrolysates have been a part of the human diet for centuries, notably in the form of fermented soy sauce, or Shoyu. Shoyu, traditionally made from wheat and soy protein, has been produced in Japan for over 1,500 years, following its introduction from mainland China. The origins of producing these materials through the acid hydrolysis of protein (aHVP) can be traced back to the scarcity and economic challenges of obtaining meat extracts during the Napoleonic wars. In 1831, Berzelius obtained products having a meat bouillon taste when hydrolysing proteins with hydrochloric acid. Julius Maggi produced acid-catalyzed hydrolyzed vegetable protein industrially for the first time in 1886. In 1906, Fischer found that amino acids contributed to the specific taste. In 1954, D. Phillips found that the bouillon odor required the presence of proteins containing threonine. Another important substance that gives a characteristic taste is glutamic acid.
=== Hypoglycemia === Hypoglycemia, or low blood glucose, can happen even with care, since insulin requirements can change without warning. Some common reasons for hypoglycemia include increased or unplanned exercise, illness, or medication interactions, where another medication potentiates the effects of the insulin. Vomiting and diarrhea episodes can bring on a hypoglycemia reaction, due to dehydration or simply a case of too much insulin and not enough properly digested food. Symptoms of hypoglycemia need to be taken seriously and addressed promptly. Since serious hypoglycemia can be fatal, it is better to treat a suspected incident than to fail to respond quickly to the signs of actual hypoglycemia. Dr. Audrey Cook addressed the issue in her 2007 article on diabetes mellitus: "Hypoglycemia is deadly; hyperglycemia is not. Owners must clearly understand that too much insulin can kill, and that they should call a veterinarian or halve the dose if they have any concerns about a pet's well-being or appetite. Tell owners to offer food immediately if the pet is weak or is behaving strangely."
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.
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.