Everything below concerns Melanotan II. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-08-01. Numbers and descriptions here follow the published literature rather than marketing material.
Receptor-binding studies classify melanotan II as a non-selective melanocortin agonist. It interacts with MC1R, MC3R, MC4R and MC5R, with reported affinities in the low nanomolar range and no strong subtype preference. Activation of MC1R on dermal melanocytes shifts pigment synthesis toward eumelanin, the dark polymer deposited in melanosomes and transferred to keratinocytes. Because the same peptide engages MC4R in the hypothalamus, it also appears in animal work on food intake and erectile response, which is why it is discussed in both pigment and metabolic research. Which receptor populations dominate after systemic exposure in humans is not fully established.
Published pharmacokinetic information is limited and comes mainly from small studies rather than registrational trials. Plasma half-life is usually described as short, on the order of tens of minutes, followed by rapid tissue distribution and clearance of the intact peptide. Metabolites and low concentrations of parent compound have been reported in urine, a detail relevant to anti-doping and forensic testing. Whether repeated exposure changes receptor sensitivity or clearance over time remains an open question. Values differ noticeably between analytical assays, so published numbers should be read as approximate rather than definitive.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C50H69N15O9 | Cyclic heptapeptide, C-terminally amidated |
| Approximate molecular mass | 1024 Da | Monoisotopic mass of the free peptide |
| Appearance | White to off-white powder | Typically supplied as a lyophilised solid |
| Solubility class | Soluble in water and polar solvents | Also dissolves in neutral aqueous buffer |
| Common synonyms | Melanotan II, MT-II, MT-2 | Described as a melanocortin agonist in early literature |
=== Pseudovitamins and antivitamins === Pseudovitamin B12 refers to compounds that are corrinoids with a structure similar to the vitamin, but without vitamin activity. Pseudovitamin B12 is the majority corrinoid in spirulina, an algal dietary supplement sometimes erroneously claimed as having this vitamin activity. Antivitamin B12 compounds (often synthetic B12 analogues) not only have no vitamin action, but also actively interfere with the activity of true vitamin B12. The design of these compounds mainly involves the replacement of the metal ion with rhodium, nickel, or zinc, or may have an inactive ligand attached, such as 4-ethylphenyl. These compounds have the potential for use in analyzing B12 pathways or even attacking B12-dependent pathogens.
If this is the case, such a duplication must have happened early in animal evolution (more than 700 million years ago), as genes that encode for all three subunits of troponin have been found in every invertebrate phyla except the Cnidaria (or equivalently, all Bilaterian phyla). The ancestral gene pair most closely resembled TNNI2-TNNT3.
All security responsibilities were then assumed by the Iraqi Armed Forces and other security agencies, including the Ministry of Interior. The Office of Security Cooperation - Iraq, part of the larger Embassy of the United States, Baghdad held the remaining DOD support personnel, totalling about 1,000 contractors and about 147 DOD uniformed personnel. It operated from ten locations around Iraq, and managed about 370 Foreign Military Sales cases, totaling more than US $9 billion of pending arms sales, citing a February 2012 Congressional Research Service report; training; and follow-on support functions. The biggest program underway was the much-delayed sale of 18 Lockheed Martin F-16 Fighting Falcon fighters.
== Research == Mark Crislip, a practicing infectious disease specialist, examined the claims that bee venom can treat arthritis. He was unable to "find a clean, i.e., a non-TCPM based, randomized, placebo-controlled study of bee venom in humans for the treatment [of] arthritis." Bee venom is also considered ineffective for the treatment or prevention of cancer, with no clinical studies to date supporting such effects. According to the American Cancer Society, there is no scientific evidence that apitherapy or bee venom therapy can treat or change the course of cancer or any other disease. Clinical trials have shown that apitherapy is ineffective in treating multiple sclerosis or any other disease, and can exacerbate multiple sclerosis symptoms.
== Greek fortifications == The oldest discoveries were made in the northwestern part and involved a portion of the north–south road which dates back to the 6th century BC. A first rampart made up of a white limestone base from Saint-Victor surmounted by an elevation in raw clay bricks dating from the end of the 5th century BC was also discovered. These fortifications must have been contemporaneous with the large public well, which has now disappeared, located to the north of the area. This archaic rampart was then rebuilt, probably in the second half of the 4th century BC. This new rampart seems to have included, like the previous one, a stone plinth surmounted by an elevation made of large blocks of tuff which replaced the raw bricks. A gate opening onto the route d'Italie in an east–west direction is flanked by two towers or bastions. This wall is clearly visible in the northwest corner of the current garden, preceded by a ditch. In the second half of the 2nd century BC, the rampart was rebuilt on a large scale, this time in blocks of pink limestone from Cape Couronne, transported by boat. It is this rampart that defended the city during the siege of Julius Caesar in 49 BC. It would remain in use until the beginning of the Middle Ages. The wall was built according to a usual technique of Greek military architecture with two facings built with standardized blocks, the interior being filled with residues from the cutting of blocks or stones from the old rampart. From north to south are:
Sources: en.wikipedia.org
==== Other materials ==== Paraffin wax does not always provide a sufficiently hard matrix for cutting very thin sections (which are especially important for electron microscopy). Paraffin wax may also be too soft in relation to the tissue, the heat of the melted wax may alter the tissue in undesirable ways, or the dehydrating or clearing chemicals may harm the tissue. Alternatives to paraffin wax include, epoxy, acrylic, agar, gelatin, celloidin, and other types of waxes. In electron microscopy epoxy resins are the most commonly employed embedding media, but acrylic resins are also used, particularly where immunohistochemistry is required. For tissues to be cut in a frozen state, tissues are placed in a water-based embedding medium. Pre-frozen tissues are placed into molds with the liquid embedding material, usually a water-based glycol, OCT, TBS, Cryogen, or resin, which is then frozen to form hardened blocks.
=== Food Industry === Acid dyes can also be used as food colouring, helping to increase the attractiveness of certain foods, and thus becoming more appealing to customers. Some examples include erythrosine (red-pink), tartrazine (yellow), sunset yellow, and allura red, to name a few, many of which are azo dyes. These dyes can be used in frosting, cookies, bread, condiments or drinks. In order to prevent health hazards, a dye must be approved for consumption before it can be marked as edible. Some separation methods that can be used to identify unapproved dyes include the solid phase extraction process, the overpressured thin layer chromatography process, and the use of reversed-phase plates.
== Biological role == Surface proteins of Gram-positive bacteria play an important role in the pathogenesis of human infections such as Clostridioides difficile infection. These surface/adhesion proteins mediate the initial attachment of bacteria to host tissues. These proteins are covalently linked to the peptidoglycan of the bacterial cell wall. As more and more pathogens become resistant to antibiotics, inhibition of sortases may offer a novel strategy against gram-positive bacterial infections. SrtB, in particular, has gained much attention and is recognized as a promising target and deletion of its gene in gram-positive bacteria will lead to serious virulence defects. Crystal structures of these SrtB enzymes from different species have been solved with ligands/inhibitors bound to their active site. With knowledge of the active site, the development of better therapeutics against these bacteria species can be done.
Peak areas are calculated from HPLC traces of dry samples of the substance to be tested in 1 ml of acetonitrile. The standard used to calibrate the calculation is 1 gram of capsaicin. Scoville heat units are found by multiplying the ppmH value by a factor of 15. By this definition of ppmH, spicy compounds other than the two most important capsaicinoids are ignored, despite the ability of HPLC to measure these other compounds at the same time.
Sources: en.wikipedia.org
== Usage == Zinc L-carnosine has been used orally or as an oral rinse, lozenge or suppository. The typical clinical oral dose is 150 mg/day, containing 34 mg zinc and 116 mg L-carnosine. (The Tolerable Upper Intake Level (UL) for total zinc intake from all sources in adults is 40 mg/day.) As an oral rinse, it has been used three to four times a day, with or without swallowing, providing a total amount of 150 mg/day. A solution of 5% sodium alginate has been used. Alternatively, it has been used as a lozenge containing 18.75 mg, four times a day. It has also been used as a suppository of 75 mg with Witepsol as a base.
Modified atmosphere packaging (MAP) is the practice of modifying the composition of the internal atmosphere of a package (commonly food packages, drugs, etc.) in order to improve the shelf life. The need for this technology for food arises from the short shelf life of food products such as meat, fish, poultry, and dairy in the presence of oxygen. In food, oxygen is readily available for lipid oxidation reactions. Oxygen also helps maintain high respiration rates of fresh produce, which contribute to shortened shelf life. From a microbiological aspect, oxygen encourages the growth of aerobic spoilage microorganisms. Therefore, the reduction of oxygen and its replacement with other gases can reduce or delay oxidation reactions and microbiological spoilage. Oxygen scavengers may also be used to reduce browning due to lipid oxidation by halting the auto-oxidative chemical process. MAP achieves changes in the gaseous atmosphere by incorporating different compositions of gases. The modification process generally lowers the amount of oxygen (O2) in the headspace of the package. Oxygen can be replaced with nitrogen (N2), a comparatively inert gas, or carbon dioxide (CO2). A stable atmosphere of gases inside the packaging can be achieved using active techniques, such as gas flushing and compensated vacuum, or passively by designing "breathable" films.
Sociologist Robert K. Merton believed deviance depended on society's definition of success, and the desires of individuals to achieve success through socially defined avenues. Criminality becomes attractive when expectations of being able to fulfill goals (therefore achieving success) by legitimate means cannot be fulfilled. Criminal organizations capitalize on states with a lack of norm by imposing criminogenic needs and illicit avenues to achieve them. This has been used as the basis for numerous meta-theories of organized crime through its integration of social learning, cultural deviance, and criminogenic motivations. If crime is seen as a function of anomie, organized behavior produces stability, increases protection or security, and may be directly proportional to market forces as expressed by entrepreneurship- or risk-based approaches. It is the inadequate supply of legitimate opportunities that constrains the ability for the individual to pursue valued societal goals and reduces the likelihood that using legitimate opportunities will enable them to satisfy such goals (due to their position in society).
Thyroglobulin (Tg) acts as a substrate for the synthesis of the thyroid hormones thyroxine (T4) and triiodothyronine (T3), as well as the storage of the inactive forms of thyroid hormone and iodine within the follicular lumen of a thyroid follicle. Newly synthesized thyroid hormones (T3 and T4) exist as prohormonal modified tyrosine residues of thyroglobulin, which comprise the colloid within the follicle. When stimulated by thyroid stimulating hormone (TSH), the colloid of the follicular lumen is endocytosed into the surrounding thyroid follicular epithelial cells. When endosomes fuse with lysosomes in these cells, Tg is subsequently cleaved by proteases to release thyroglobulin from its T3 and T4 attachments. Because of the hydrophobic nature of T3 and T4, they are able to then diffuse across the lysosomal membrane and into the cytoplasm. The active forms of thyroid hormone (T3 and T4), are then released into circulation where they are either unbound or attached to plasma proteins. Iodine is recycled back into the follicular lumen where it can continue to serve as a substrate for thyroid hormone synthesis, while the non-modified residues of Tg reenter cellular metabolic pathways.
In the early 1950s, Alexander Todd's group pioneered H-phosphonate and phosphate triester methods of oligonucleotide synthesis. The reaction of compounds 1 and 2 to form H-phosphonate diester 3 is an H-phosphonate coupling in solution while that of compounds 4 and 5 to give 6 is a phosphotriester coupling (see phosphotriester synthesis below).
Sources: en.wikipedia.org
No. It is a synthetic analogue carrying four amino acid changes, a lactam ring and an amidated C-terminus. The natural hormone is a linear thirteen-amino-acid peptide processed from proopiomelanocortin.
Afamelanotide is the linear analogue [Nle4-D-Phe7]-alpha-MSH, sometimes called melanotan I, while melanotan II is cyclic and carries three further substitutions. The two are distinct molecules and are not interchangeable in analytical testing.
Binding to the four melanocortin receptor subtypes is well documented in vitro. The relative contribution of each subtype to whole-body effects in humans is far less certain.
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.