A practical reference on alpha-MSH analogue: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2025-09-25 and is reviewed periodically as new material appears.
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.
The peptide was developed during the 1980s by researchers investigating melanocortin signalling and skin pigmentation pathways. Early work focused on analogues of alpha-melanocyte-stimulating hormone that would resist enzymatic breakdown more effectively than the parent molecule. Melanotan-2 emerged from that programme as a shortened, cyclised variant. Reports describing its synthesis and receptor activity later appeared in the scientific literature. Commercial availability grew through unregulated channels rather than through pharmaceutical approval.
Structurally, Melanotan-2 retains the core recognition motif of alpha-melanocyte-stimulating hormone while adding a lactam bridge that links two side chains and constrains the molecule into a ring. This modification lowers susceptibility to enzymatic degradation. The compound acts as an agonist at melanocortin receptors, particularly subtypes associated with melanin production. Because the same receptor family influences several physiological processes, researchers note that its activity is not confined to pigmentation alone. Receptor selectivity continues to be examined in published studies.
Melanotan-2 is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone, a naturally occurring peptide involved in pigmentation signalling. Its sequence incorporates modified residues that increase potency and extend biological activity relative to the native hormone. The compound binds receptors of the melanocortin family and is examined mainly in laboratory research. It does not occur naturally and exists only as a manufactured chemical entity produced by solid-phase synthesis.
| Property | Value | Notes |
|---|---|---|
| Compound class | Synthetic cyclic heptapeptide | Alpha-MSH analogue containing a D-phenylalanine residue |
| Molecular formula | C50H69N15O9 | Average molecular mass approximately 1024.2 g/mol |
| Appearance | White to off-white lyophilised powder | Normally supplied as a freeze-dried solid in a sealed vial |
| Solubility | Freely soluble in water and polar solvents | Dissolves readily in aqueous buffers and in alcohol-water mixtures |
| Receptor targets | MC1R, MC3R, MC4R, MC5R | Acts as a non-selective melanocortin receptor agonist |
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.
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.
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.
The result of the Jeddah talks was an Iraqi demand for $10 billion to cover the lost revenues from Rumaila. Kuwait offered $500 million. The Iraqi response was to immediately order an invasion, which started on 2 August 1990 with the bombing of Kuwait's capital, Kuwait City. Before the invasion, the Kuwaiti military was believed to have numbered 16,000 men, arranged into three armored, one mechanized infantry and one under-strength artillery brigade. The pre-war strength of the Kuwait Air Force was around 2,200 Kuwaiti personnel, with 80 fixed-wing aircraft and 40 helicopters. In spite of Iraqi sabre-rattling, Kuwait did not mobilize its force; the army had been stood-down on 19 July, and during the Iraqi invasion many Kuwaiti military personnel were on leave. By 1988, at the end of the Iran–Iraq war, the Iraqi Army was the world's fourth largest army, consisting of 955,000 standing soldiers and 650,000 paramilitary forces in the Popular Army. A low estimate shows the Iraqi Army capable of fielding 4,500 tanks, 484 combat aircraft and 232 combat helicopters. A high estimate shows the Iraqi Army capable of fielding one million troops and 850,000 reservists, 5,500 tanks, 3,000 artillery pieces, 700 combat aircraft and helicopters; it held 53 divisions, 20 special-forces brigades, and several regional militias, and had a strong air defense.
Naturally occurring rhodium is composed of only one isotope, 103Rh. With a nuclear spin of -1/2, 103Rh is well-suited for nuclear magnetic resonance spectroscopic studies. With a particularly low nuclear dipole moment, 103Rh exhibits very low receptivity. The most stable radioisotopes are 101Rh with a half-life of 4.07 years, 102Rh with a half-life of 207 days, and 99Rh with a half-life of 16.1 days. Thirty-eight other radioisotopes have been characterized ranging from 90Rh to 128Rh; these have half-lives that are less than an hour except 100Rh (20.8 hours) and 105Rh (35.34 hours). Numerous meta states are also known, of which the most stable are 102mRh (3.742 years) and 101mRh (4.343 days). In isotopes lighter than 103Rh (the stable isotope), the primary decay mode is electron capture and the primary decay product is ruthenium. In isotopes heavier than 103Rh, the primary decay mode is beta emission and the primary product is palladium.
== Sinking bubbles == When Guinness is poured, the gas bubbles appear to travel downwards in the glass. The effect is attributed to drag; bubbles that touch the walls of a glass are slowed in their travel upwards. Bubbles in the centre of the glass are, however, free to rise to the surface, and thus form a rising column of bubbles. The rising bubbles create a current by the entrainment of the surrounding fluid. As beer rises in the centre, the beer near the outside of the glass falls. This downward flow pushes the bubbles near the glass towards the bottom. Although the effect occurs in any liquid, it is particularly noticeable in any dark nitrogen stout, as the drink combines dark-coloured liquid and light-coloured bubbles. A study published in 2012 revealed that the effect is due to the particular shape of the glass coupled with the small bubble size found in stout beers. If the vessel widens with height, then bubbles will sink along the walls – this is the case for the standard pint glass. Conversely, in an anti-pint (i.e. if the vessel narrows with height) bubbles will rise along the walls.
=== Society === Little is revealed of the Combine's activities outside of Earth, but dialogue in Half-Life 2 states that they control worlds of various dimensions inhabited by a range of species. The Combine occupation of Earth is shown to be a brutal totalitarian police state. In City 17, an Eastern European city, Civil Protection units routinely conduct searches of apartment blocks, interrogating human citizens, and engaging in wanton police brutality. The military Overwatch forces of the Combine attack human resistance bases in an effort to further solidify their authority in the urban centers. Human citizens are clad in blue uniforms, living in designated apartment blocks and move around to different cities or locales in passenger trains by the Combine's will. Vortigaunts, enemy alien creatures from Half-Life, have also been enslaved, and are observed in various professions such as janitors. According to Half-Life 2: Raising the Bar, the Combine are draining Earth's oceans and resources to be used on other Combine worlds. The heart of the Combine's command over Earth in Half-Life 2 is the Citadel, a large tower constructed by them which reaches both tens of thousands of feet (several or several tens of kilometres) into the sky and deep underground. Located within City 17, the Citadel serves as the Combine's headquarters on Earth, housing Combine Advisors and the office of Earth's administrator, Dr. Wallace Breen. Breen, a puppet ruler, is frequently seen on large screens around the city on which he spreads propaganda and makes announcements.
Sources: en.wikipedia.org
Burger King's headquarters experienced major damage in 1992 from Hurricane Andrew. After Gibbons's departure, a series of CEOs each tried to repair the company's brand by changing the menu, bringing in new ad agencies and many other changes. The parental disregard of the Burger King brand continued with Grand Metropolitan's merger with Guinness in 1997 when the two organizations formed the holding company Diageo. Eventually, the ongoing systematic institutional neglect of the brand through a string of owners damaged the company to the point where major franchises were driven out of business, and its total value was significantly decreased. Diageo eventually decided to divest itself of the money-losing chain and put the company up for sale in 2000.
=== Stem-wind, lever-set movements === Mandatory for all railroad watches after roughly 1908, this kind of pocket watch was set by opening the crystal and bezel and pulling out the setting-lever (most hunter-cases have levers accessible without removing the crystal or bezel), which was generally found at either the 10 or 2 o'clock positions on open-faced watches, and at 5:00 on hunting cased watches. Once the lever was pulled out, the crown could be turned to set the time. The lever was then pushed back in and the crystal and bezel were closed over the dial again. This method of time setting on pocket watches was preferred by American and Canadian railroads, as lever setting watches make accidental time changes impossible. After 1908, lever setting was generally required for new watches entering service on American railroads.
=== Therapeutics === There are therapeutics used clinically which can effect the activity of P-type calcium channels. However, the primary target of these therapeutics are not thought to be P-type channels. For example, calcium antagonists, which are used to treat coronary heart disease, hypertension, and cardiac arrhythmia, act by inhibiting L-type or T-type calcium channels. Some of these calcium antagonists include verapamil, diltiazem, amlodipine, benidipine, cilnidipine, nicardipine, and barnidipine. Although their main target is not P-type channels, these calcium antagonists also act to block the function of P-type channels. Moreover, flunarizine is another calcium antagonist which is used to treat migraines. Its main targets are voltage-gated calcium channels and sodium channels. Flunarizine inhibits the P-type channels that are located in the neocortical slices. It works to inhibit the inward flux of calcium. The migraines that it helps to prevent are due to mutations within the "cacna1a" gene of the P-type channel subunit. Also, compounds that block P-type channels are shown to help with seizures. Epileptic seizures are caused by increased neurotransmission, which is partially a result of P-type channels. Compounds such as levetiracetam, lamotrigine, and carbamazepine are known to block the P-type channels, which have helped to decrease the occurrence of seizures.
Instrumentation can control sampling, reagent use, reaction times, signal detection, calculation of results, and data management to yield a cost-effective automated process for diagnosis of infectious disease.
Decarboxylation is a chemical reaction that removes a carboxyl group and releases carbon dioxide (CO2). Usually the term refers to a reaction of carboxylic acids, removing a carbon atom from a carbon chain. The reverse process, which is the first chemical step in photosynthesis, is called carboxylation, the addition of CO2 to a compound. Enzymes that catalyze decarboxylations are called decarboxylases or, more formally, carboxy-lyases (EC number 4.1.1).
Sources: en.wikipedia.org
=== HAT tag === The HAT tag is a peptide tag (KDHLIHNVHKEEHAHAHNK) derived from chicken lactate dehydrogenase, and is more likely to be a soluble protein with no bias in charge distribution compared to the His tag. The arrangement of histidines in the HAT tag allows high accessibility compared to the His tag, and it binds efficiently to the immobilized metal ion.
The emperor was dressed in his interment attire: the court dress uniform of a Marshal of the Imperial Brazilian Army, with the star of the Imperial Order of the Cross on his chest. He also wore the Order of the Golden Fleece and the collar of the Imperial Order of the Rose, while his hands clutched a silver crucifix sent by Pope Leo XIII. Despite recognizing the body's overall preservation, however, d'Escragnolle Dória felt that the embalming had not fully succeeded in maintaining the emperor's appearance. He wrote: His face resembles old wax. His beard, once so fine, silky, and white, has turned a dull yellow, like aged ivory. When I saw him in February 1912, I found him smaller than he had been in late 1909. The head of Dom Pedro II rests on a pillow filled with Brazilian soil. The emperor looks so different! How cruel is an imperfect embalming! Where is that majestic head, once crowned with silvery hair? Where are his steel-blue eyes, his beautiful beard—gilded by youth and silvered by age—and his stately bearing? Everything is gone, faded!
Initially, this development was not regarded by the medical profession as a clinically meaningful development. However, by 1996, the advent of insulin analogues which had vastly improved absorption, distribution, metabolism, and excretion (ADME) characteristics which were clinically meaningful based on this early biotechnology development. In 2005, a new drug to treat type 2 diabetes, derived from the Gila monster, was approved by the Food and Drug Administration. The venom of the lizard contains exendin 4, which triggers one of the insulin-releasing pathways.
Filtering helps stabilise the flavour of beer, holding it at a point acceptable to the brewer, and preventing further development from the yeast, which under poor conditions can release negative components and flavours. Filtering also removes haze, producing a clear beer with a "polished shine and brilliance". Clear beer became commercially desirable with the increasing use of glass drinking vessels and the development of pale lagers. During lagering, suspended material settles out, allowing the beer to "drop bright" and develop a naturally clear appearance. There are several forms of filters; they may be in the form of sheets or "candles", or they may be a fine powder such as diatomaceous earth (also called kieselguhr), which is added to the beer to form a filtration bed which allows liquid to pass, but holds onto suspended particles such as yeast. Filters range from rough filters that remove much of the yeast and any solids (e.g., hops, grain particles) left in the beer, to filters tight enough to strain colour and body from the beer. Filtration ratings are divided into rough, fine, and sterile. Rough filtration leaves some cloudiness and some character in the beer, while Fine filtration removes almost all cloudiness and microorganisms. Polysaccharides, proteins, yeast, bacteria and the brewing process may affect filtration.
Sources: en.wikipedia.org
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.
No approved regulatory indication exists in major markets. An approval exists for a different peptide, afamelanotide, which is used for a rare photosensitivity disorder called erythropoietic protoporphyria. Melanotan-2 itself remains a research compound with no cleared clinical role.
Melanocortin-1 receptors on melanocytes are the receptor most closely linked to pigment production. The peptide is not selective, however, and also activates melanocortin-3, melanocortin-4, and melanocortin-5 receptors. That lack of selectivity is the usual explanation offered for both its range of observed effects and its off-target effects.
It is a synthetic cyclic heptapeptide and an analogue of alpha-melanocyte-stimulating hormone. The molecule is produced by chemical synthesis rather than extracted from a biological source.