If you have been reading about alpha-MSH analogue and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Updated 2026-01-16. 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.
Melanotan II is a synthetic cyclic heptapeptide with the sequence Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, corresponding to a molecular formula of C50H69N15O9 and a monoisotopic mass near 1024 daltons. It was designed as a structural analogue of alpha-melanocyte-stimulating hormone, a peptide hormone produced by cleavage of proopiomelanocortin. A lactam bridge between the aspartate and lysine side chains closes the ring, and the C-terminal amide removes a free carboxyl group. Both modifications increase resistance to enzymatic degradation compared with the linear parent hormone. Four substitutions distinguish it from afamelanotide, the linear analogue studied under the name melanotan I.
Regulatory status differs by country, and in many places supplying the compound for human consumption is unlawful. Vendors frequently label material as intended for research use only, a designation that shifts stated purpose but does not create a legal pathway for personal use. Certificates of analysis accompanying such products vary widely in detail and provenance. Third-party testing exists but is voluntary, and results are rarely linked to a specific lot in a publicly verifiable way.
Identity testing for a synthetic peptide relies on several complementary methods. Reversed-phase high-performance liquid chromatography separates the target from related impurities and reports purity as a percentage of total peak area. Mass spectrometry confirms molecular mass and can reveal deletions or truncations. Amino acid analysis and peptide mapping provide sequence-level confirmation, while counter-ion content and residual solvents are measured separately. A purity figure alone does not establish identity, so a complete dataset combines chromatographic and spectrometric evidence.
| 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 |
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.
Regulatory treatment varies by country. In the United States, melanotan-2 is not approved for any indication, and products marketed for human use fall outside the approved drug framework. Some other jurisdictions have placed it under prescription controls or listed it as a prohibited or restricted substance. Online listings frequently describe the material as a research chemical, a category that does not carry the same manufacturing and labelling requirements as approved medicines.
Solid peptide material is generally stable when kept cold and dry. Common practice is storage at -20 degrees Celsius or lower, with desiccant and protection from light. Repeated freeze-thaw cycles and exposure to moisture are associated with degradation, aggregation, or loss of material. Once dissolved, stability depends on solvent, concentration, and temperature, and solutions are usually treated as short-lived unless stability data support longer periods. Handling notes typically emphasise minimising time at ambient temperature.
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.
Identity and purity are assessed mainly by reversed-phase high-performance liquid chromatography with ultraviolet detection, often paired with mass spectrometry. Retention time supports identity, while the mass spectrum confirms the molecular weight of the intact peptide. Purity is frequently reported as a percentage of total peak area, a figure that depends on the wavelength, column and gradient used. Impurity profiling may also look for truncated sequences, oxidised forms and residual counterions. Amino acid analysis and peptide mapping provide orthogonal confirmation when required.
Regulatory status varies by jurisdiction, and the substance is frequently described as unapproved for therapeutic use. Some authorities classify it alongside prescription-only medicines or controlled categories, while others address it through general consumer protection rules. Analytical surveys have reported mismatches between label claims and measured content in products sold online, although the scope of such testing is limited. Whether these discrepancies are widespread remains an open question. Discussion in the literature therefore tends to combine chemistry, supply-chain observation and policy analysis.
The material is commonly handled as a lyophilized powder in sealed vials. The solid dissolves readily in water and in polar organic solvents, producing a clear solution after reconstitution. Light, heat and repeated freeze-thaw cycles are the concerns most often raised in handling guidance, because peptide bonds and the constrained ring can degrade. Working solutions are generally prepared fresh, and material left in solution is treated as less stable than the dry form. These properties shape how laboratories store and aliquot reference material.
Military supply-chain management is a cross-functional approach to procuring, producing, and delivering products and services for military materiel applications. Military supply chain management includes sub-suppliers, suppliers, internal information and funds flow.
The research, as cited by the cover story of the November 2005 issue of National Geographic, asserts that Adventists live longer because they do not smoke or drink alcohol, have a day of rest every week, and maintain a healthy, low-fat vegetarian diet that is rich in nuts and beans. The cohesiveness of Adventists' social networks has also been put forward as an explanation for their extended lifespan. Since Dan Buettner's 2005 National Geographic story about Adventist longevity, his book, The Blue Zones: Lessons for Living Longer From the People Who've Lived the Longest, named Loma Linda, California, a "blue zone" because of the large concentration of Seventh-day Adventists. He cites the Adventist emphasis on health, diet, and Sabbath-keeping as primary factors for Adventist longevity. An estimated 35% of Adventists practice vegetarianism or veganism, according to a 2002 worldwide survey of local church leaders. North American Adventist health study recruitments from 2001 to 2007 found a similar prevalence of vegetarianism/veganism. A small majority of Adventists, 54%, were conventional meat-eaters. Of the remaining 46% it was found that 28% were Ovo/Lacto-vegetarians, 10% were Pesco-vegetarians and 8% were vegans. It is common for Adventists who choose to eat meat to also eat plant-based foods; 6% of the "meat-eaters" group restricted their intake of meat/fish to no more than once per week.
Vitamin B12 is the most chemically complex of all the vitamins. The structure of B12 is based on a corrin ring, which is similar to the porphyrin ring found in heme. The central metal ion is cobalt. As isolated as an air-stable solid and available commercially, cobalt in vitamin B12 (cyanocobalamin and other vitamers) is present in its +3 oxidation state. Biochemically, the cobalt center can take part in both two-electron and one-electron reductive processes to access the "reduced" (B12r, +2 oxidation state) and "super-reduced" (B12s, +1 oxidation state) forms. The ability to shuttle between the +1, +2, and +3 oxidation states is responsible for the versatile chemistry of vitamin B12, allowing it to serve as a donor of deoxyadenosyl radical (radical alkyl source) and as a methyl cation equivalent (electrophilic alkyl source).
== Reactions == The cycle comprises three enzyme-catalysed reactions. The first stage is the deamination of the purine nucleotide adenosine monophosphate (AMP) to form inosine monophosphate (IMP), catalysed by the enzyme AMP deaminase:
In June 2024, Adam Hamawy, a former US army combat surgeon who worked in the European Hospital, stated, "But the level of civilian casualties that I experienced was beyond anything I'd seen before... Most of our patients were children under the age of 14". In August 2024, an Israeli airstrike killed Joumana Arafa and her four-day-old twins.
Sources: en.wikipedia.org
== Anatomy == The pericardium is a tough fibroelastic sac which covers the heart from all sides except at the cardiac root (where the great vessels join the heart) and the bottom (where only the serous pericardium exists to cover the upper surface of the central tendon of diaphragm). The fibrous pericardium is semi-rigid, while the serous pericardium is quite pliable. The same mesothelium that constitutes the serous pericardium also covers the heart as the epicardium, resulting in a continuous serous membrane invaginated onto itself as two opposing surfaces (over the fibrous pericardium and over the heart). This creates a pouch-like potential space around the heart enclosed between the two opposing serosal surfaces, known as the pericardial space or pericardial cavity, which is filled with a small amount of serous fluid to lubricate the heart's movements and cushions it from any external jerk or shock.
In the United States between 2020 and 2022, the number of e-cigarettes sold had climbed to 22.7 million units. Elf Bar/EBDESIGN, Vuse, JUUL, NJOY and Breeze Smoke were recognized as the five most popular brands as of December 2022. The surge was driven by non-tobacco flavors such as menthol (for prefilled cartridges) and fruit and candy (for disposables), according to the CDC's health economist Fatma Romeh Ali. In the UK, where most vaping uses refillable sets and e-liquid, there is now support from the National Health Service, and other medical bodies now embrace the use of e-cigarettes as a viable way to quit smoking. This has contributed to record numbers of people vaping, with an estimated 3.6 million in 2021. Nationally, about 7% of children and teenagers (aged 11–17) currently vape, which equates to roughly 400,000 children in Great Britain. Additionally, around 20% of young people have tried vaping at least once. Many vape brands are popular such as Lost mary Bm600 disposables (one use products) and The R and M Tornado 9000. "In 2025, reports highlighted the rise of illegal 'mega vapes' being sold to minors."
Humankind gradually evolved from early members of the genus Homo—such as Homo habilis, who used simple stone tools—into anatomically modern humans as well as behaviourally modern humans by the Upper Paleolithic. During the end of the Paleolithic Age, specifically the Middle or Upper Paleolithic Age, humans began to produce the earliest works of art and to engage in religious or spiritual behavior such as burial and ritual. Conditions during the Paleolithic Age went through a set of glacial and interglacial periods in which the climate periodically fluctuated between warm and cool temperatures. By c. 50,000 – c. 40,000 BP, the first humans set foot in Australia. By c. 45,000 BP, humans lived at 61°N latitude in Europe. By c. 30,000 BP, Japan was reached, and by c. 27,000 BP humans were present in Siberia, above the Arctic Circle. By the end of the Upper Paleolithic Age humans had crossed Beringia and expanded throughout the Americas continents.
==== Pollution ==== Pollution, the presence of contaminants in an environment that causes adverse effects, could have been present as early as the Inca Empire. They used a lead sulfide flux in the smelting of ores, along with the use of a wind-drafted clay kiln, which released lead into the atmosphere and the sediment of rivers.
Sources: en.wikipedia.org
However, it is notable that the anabolic steroid methyltestosterone, which benorterone differs from in chemical structure only by the removal of a carbon atom in the B ring, is aromatized into the estrogen methylestradiol and has potent estrogenic activity. Estrogens are antigonadotropic similarly to androgens and progestogens and are likewise able to suppress testosterone levels. In accordance, the compound corresponding to what would be the aromatized form of benorterone, 17α-methyl-B-norestradiol, has been described and has been reported to possess estrogenic activity, although the aromatization of benorterone has not been assessed. A couple of studies found that prothrombin levels decreased by 50% in some patients treated with benorterone, although a causal relationship between this change and benorterone could not be shown.
=== Iraq === In a March 2000 article in The Guardian, Galloway described himself as a supporter of the Iraqi people and the Ba'ath Party, but not Saddam Hussein himself. In a House of Commons debate on 6 March 2002, Foreign Office minister Ben Bradshaw said Galloway was "not just an apologist, but a mouthpiece, for the Iraqi regime over many years." Galloway called the minister a liar and refused to withdraw on the grounds that Bradshaw's claim was "a clear imputation of dishonour", and the sitting was suspended due to the dispute. Bradshaw later withdrew his allegation, and Galloway apologised for using unparliamentary language. Giving evidence in his libel case against The Daily Telegraph in 2004, Galloway testified that he regarded Saddam as a "bestial dictator" and would have welcomed his removal from power, but not by means of a military attack on Iraq. Galloway also pointed out that he was a prominent critic of Saddam Hussein's government in the 1980s, as well as of the role of Margaret Thatcher's government in supporting arms sales to Iraq during the Iran–Iraq War.
==== Transport ==== Until recently, it was thought that the sole important retinoid delivery pathway to tissues involved retinol bound to retinol-binding protein (RBP4). More recent findings, however, indicate that retinoids can be delivered to tissues through multiple overlapping delivery pathways, involving chylomicrons, very low-density lipoprotein (VLDL) and low-density lipoprotein (LDL), retinoic acid bound to albumin, water-soluble β-glucuronides of retinol and retinoic acid, and provitamin A carotenoids. The range of serum retinol concentrations under normal conditions is 1–3 μmol/L. Elevated amounts of retinyl ester (i.e., >10% of total circulating vitamin A) in the fasting state have been used as markers for chronic hypervitaminosis A in humans. Candidate mechanisms for this increase include decreased hepatic uptake of vitamin A and the leaking of esters into the bloodstream from saturated hepatic stellate cells.
=== Mechanism of action === Elexacaftor/tezacaftor/ivacaftor is a tridrug treatment in which the medications work together to increase the transport of chloride and sodium ions and correct fluid shifts that are dysregulated in cystic fibrosis. Its effectiveness is dependent on the type of CF mutations the patient has.
This means the rule must be pursue a legitimate aim and (1) be suitable to achieve the aim, (2) be necessary, so that a less restrictive measure could not achieve the same result, and (3) be reasonable in balancing the interests of free trade with interests in article 36.
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.
Dry powder is usually held frozen, shielded from light, and kept away from moisture. Desiccant packaging limits hydrolysis during storage. Solutions are typically aliquoted and frozen once, because repeated thawing shortens useful life.