alpha-MSH analogue is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Updated 2025-08-29. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C50H69N15O9 | Synthetic cyclic heptapeptide |
| Molecular mass | Approximately 1024 g/mol | Depends on counter-ion content |
| Appearance | White to off-white powder | Commonly supplied as a lyophilised solid |
| Solubility | Freely soluble in water | Also dissolves in common aqueous buffers |
| Typical storage | -20 degrees Celsius, desiccated | Protect from light and repeated freeze-thaw |
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.
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.
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.
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.
Melanocortin receptors comprise five subtypes with distinct tissue distributions and functions. Melanotan-2 is described in the literature as a non-selective agonist that engages several of these subtypes, including MC1R, MC3R, MC4R, and MC5R. MC1R is the subtype most directly linked to melanin production in skin cells. Because the compound is not subtype-selective, its observed effects in experimental settings are generally attributed to activity across multiple receptor pathways rather than to a single target.
Melanotan-2 is a synthetic linear peptide built from seven amino acids arranged in a short chain. Its sequence is commonly written as Ac-Nle-Asp-His-D-Phe-Arg-Trp-Lys-NH2, which includes a modified N-terminus and an amidated C-terminus. The molecule belongs to the melanocortin family and acts as a receptor agonist. Structural features such as the D-phenylalanine residue and the Nle substitution are associated with increased stability against enzymatic degradation relative to the natural parent peptide.
The compound emerged from research programs in the 1980s that examined analogues of alpha-melanocyte-stimulating hormone for pigmentation and photoprotection. Investigators modified the native sequence to extend activity duration and potency. A related analogue, afamelanotide, was developed within the same broad line of inquiry and eventually gained approval in certain jurisdictions for a rare light-sensitivity condition. Melanotan-2 itself did not progress through the same regulatory route and has no approved therapeutic indication.
== Sources == This article incorporates text from a free content work. Licensed under Cc BY-SA 3.0 IGO (license statement/permission). Text taken from Drowning in Plastics – Marine Litter and Plastic Waste Vital Graphics, United Nations Environment Programme.
=== Legal status === In June 2009, a US Food and Drug Administration (FDA) advisory panel voted by a narrow margin to advise the FDA to remove Vicodin and another opioid, Percocet, from the market because of "a high likelihood of overdose from prescription narcotics and acetaminophen products". The panel also cited concerns of liver damage from their paracetamol component, which is also the main ingredient in commonly used nonprescription drugs such as Tylenol. Each year, paracetamol overdose is linked to about 400 deaths and 42,000 hospitalizations. In January 2011, the FDA asked manufacturers of prescription combination products that contain paracetamol to limit the amount of paracetamol to no more than 325 mg in each tablet or capsule within three years. The FDA also required manufacturers on all paracetamol-containing products to issue a black box warning indicating the potential risk for severe liver injury and a warning highlighting potential for allergic reactions. In August 2014, the Drug Enforcement Administration (DEA) announced that all hydrocodone combination products (HCPs) would be rescheduled from schedule III to schedule II of the Controlled Substances Act (CSA), effective in October 2014. In 2010, more than 16,000 deaths were attributed to abuse of opioid drugs. Even though there are legitimate medical uses for hydrocodone combination products, data suggest that a significant number of individuals misuse them.
In response to sustained high levels of migration and growing political pressure, the administration implemented stricter measures beginning in 2023. Biden faced criticism from immigration advocates for extending Title 42, a Trump administration border restriction that arose due to the COVID-19 pandemic, and for restarting the use of "expedited removal" of certain Central American families. In May 2023, the Biden administration approved sending 1,500 more troops to the U.S.-Mexico border as Title 42 expired. In January 2024, Biden expressed support for a proposed bipartisan immigration deal led by Senators Kyrsten Sinema and James Lankford. The proposed bipartisan bill would have allowed Department of Homeland Security (DHS) to close the border when encounters reach a seven-day average of 5,000 or exceed 8,500 in a single day. In addition, the bill would have mandated the detention of migrants seeking asylum and undergoing asylum interviews, with those failing the process repatriated to their home countries. While not addressing the status of "Dreamers", it would have changed immigration law to allow the children of those with H-1B visas to get work authorizations and freeze their legal ages while waiting for green cards, rather than face deportation once they turn 21, and provide additional funding for immigration judges. Former president Donald Trump announced his opposition to the legislation, calling on Congressional Republicans to oppose it; subsequently, leaders such as Speaker of the House Mike Johnson announced their opposition, halting further legislative action.
=== Precursor to sulfuric acid === Sulfur dioxide is an intermediate in the production of sulfuric acid, being converted to sulfur trioxide, and then to oleum, which is made into sulfuric acid. Sulfur dioxide for this purpose is made when sulfur combines with oxygen. The method of converting sulfur dioxide to sulfuric acid is called the contact process. Several million tons are produced annually for this purpose.
Domino's Pizza Israel was founded in 1990, and opened their first branch in 1993. They are operated by Elgad Pizza. As of August 2014, there are 33 branches throughout the state. There are four kosher franchises. The rights to own, operate, and franchise branches of the chain in Australia, New Zealand, France, Belgium, the Netherlands, Monaco, Luxembourg, Germany, Japan, Malaysia, Singapore, Taiwan and Cambodia are currently owned by Australian Domino's Pizza Enterprises, having bought the master franchises from the parent company in 1993 (Australian and New Zealand franchises). The Australian company also acquired several European and Asian franchises between 2013 and 2022. It acquired the Danish operations in 2019 but liquidated them in 2023. The master franchises for the UK and Ireland were purchased in 1993 by the British publicly listed Domino's Pizza Group (DPG), which acquired the master franchise for Germany in 2011, and Switzerland, Liechtenstein, and Luxembourg in August 2012 by buying the Swiss master franchise holder, with an option to acquire the Austrian master franchise as well. DPG opened its first Swedish location near the Mobilia shopping mall in Malmö in December 2016; three years later, in 2019, they announced that they would be selling all of their current businesses in the country. In Latin America, the first franchise was opened in 1988 in Colombia. During the next years, Domino's Pizza started operations in Mexico, Guatemala (1989), Chile (1991), Venezuela (1992), Dominican Republic (1993), Ecuador and Peru (1995).
Sources: en.wikipedia.org
=== Bosnia and Herzegovina === Following the general election on 3 October 2010, a process of formation of Bosnia and Herzegovina's Council of Ministers had begun. The resulting election produced a fragmented political landscape without a coalition of a parliamentary majority more than a year after the election. The centre-left Social Democratic Party, the largest party in the Federation of Bosnia and Herzegovina, and the Bosnian Serb autonomist Alliance of Independent Social Democrats, the largest party in Republika Srpska, each had 8 MPs of the total 42 MPs of the House of Representatives (28 from the Federation and 14 from Republika Srpska). Similarly, a crisis of government was also present at the local levels, as well as the Federal entity. In late 2011, the Council of Ministers (i.e. the national government) had been solved, however the country remained in a situation of perpetual political crisis, especially the Federation of Bosnia and Herzegovina. After months of dysfunction and arguments about legality, the entity's short-lived Federal Government had collapsed in February 2013. The 2014 unrest in Bosnia and Herzegovina was a series of demonstrations and riots that began in the northern town of Tuzla on 4 February 2014 but quickly spread to multiple cities in Bosnia and Herzegovina, including Sarajevo, Zenica, Mostar, Jajce, and Brčko, among others, for social reasons and with the aim of overthrowing the government. The riots were the most violent scenes the country had seen since the end of the Bosnian War in 1995.
Rutherford was the first to realize that all such elements decay in accordance with the same mathematical exponential formula. Rutherford and his student Frederick Soddy were the first to realize that many decay processes resulted in the transmutation of one element to another. Subsequently, the radioactive displacement law of Fajans and Soddy was formulated to describe the products of alpha and beta decay. The early researchers also discovered that many other chemical elements, besides uranium, have radioactive isotopes. A systematic search for the total radioactivity in uranium ores also guided Pierre and Marie Curie to isolate two new elements: polonium and radium. Except for the radioactivity of radium, the chemical similarity of radium to barium made these two elements difficult to distinguish. Marie and Pierre Curie also coined the term "radioactivity" to define the emission of ionizing radiation by some heavy elements. (Later the term was generalized to all elements.) Their research on the penetrating rays in uranium and the discovery of radium launched an era of using radium for the treatment of cancer. Their exploration of radium could be seen as the first peaceful use of nuclear energy and the start of modern nuclear medicine.
== External links == Deutsch M (17 June 2016). "Guidelines for the Primary and Gender-Affirming Care of Transgender and Gender Nonbinary People" (2nd ed.). University of California, San Francisco: Center of Excellence for Transgender Health. p. 28. Bourns A (2015). "Guidelines and Protocols for Comprehensive Primary Care for Trans Clients" (PDF). Sherbourne Health Centre. Retrieved 15 August 2018. Transgender HRT Research Repository Archived 2022-09-14 at the Wayback Machine
== Nomenclature == This enzyme is a transferase, specifically one transferring phosphorus-containing groups (phosphotransferases) with a phosphate group as acceptor. The systematic name of this enzyme class is ATP:(d)GMP phosphotransferase. Other names in common use include"
Sources: en.wikipedia.org
Their lean build and energy-conserving strategy allow a lower daily food intake than if they were more strongly muscled, yet with enough strength to commonly take bird prey as large as themselves, and occasionally larger. The success of this body style and hunting strategy is reflected in the high success of the species in densely populating a large range throughout the Americas. The flight of the American kestrel is not so dramatic and swift as more muscular falcons such as merlins and peregrines, but their efficient adaptation to a broader diet of more available smaller prey, and need for less food per day, has resulted in their greater population. In contrast to many other raptor species, the sexes differ more in plumage than in size. Males have blue-gray wings with black spots and white undersides with black barring. The back is rufous, with barring on the lower half. The belly and flanks are white with black spotting. The tail is also rufous, with a white or rufous tip and a black subterminal band. The back and wings of the female American kestrel are rufous with dark brown barring. The undersides of the females are creamy to buff with heavy brown streaking. The tail is noticeably different from the male's, being rufous in color with numerous narrow dark black bars. Juveniles exhibit coloration patterns similar to the adults'. In both sexes, the head is white with a bluish-gray top. There are also two narrow, vertical black facial markings on each side of the head, while other falcons have one.
Peptides are very useful as therapeutic and diagnostic substances. Their use is getting more popular, and display systems offer a useful way to engineer peptides and optimise their binding capabilities. Cells express surface proteins which can be involved in a whole host of responses including recognition of other cells, interaction with other cells, and cell signalling. Many types of bacteria have cell surface proteins such as the enteropathogenic E. coli intimin protein which is involved in binding to host cells, or the OmpA protein of E. coli cells which is important in keeping the structure of the outer membrane. Many surface proteins are involved in bacterial cell attachment and invasion of the host cell. By using bacterial display, target proteins on the host cell can be identified. These surface proteins need to first be translocated across the bacterial cell membranes from the cytoplasm to the cell surface. Gram-negative bacteria have an additional periplasmic space, which Gram-positive bacteria lack, so they have a harder task of translocating proteins. The display of heterologous proteins on the bacterial cell surface normally requires the fusion of the protein with a surface protein, called a scaffold.
Isotope masses from: Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001 Isotopic compositions and standard atomic masses from: de Laeter, John Robert; Böhlke, John Karl; De Bièvre, Paul; Hidaka, Hiroshi; Peiser, H. Steffen; Rosman, Kevin J. R.; Taylor, Philip D. P. (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry. 75 (6): 683–800. doi:10.1351/pac200375060683. Wieser, Michael E. (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry. 78 (11): 2051–2066. doi:10.1351/pac200678112051. "News & Notices: Standard Atomic Weights Revised". International Union of Pure and Applied Chemistry. 19 October 2005. Half-life, spin, and isomer data selected from the following sources. Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001 National Nuclear Data Center. "NuDat 3.0 database". Brookhaven National Laboratory. Holden, Norman E. (2004). "11. Table of the Isotopes". In Lide, David R. (ed.). CRC Handbook of Chemistry and Physics (85th ed.). Boca Raton, Florida: CRC Press. ISBN 978-0-8493-0485-9.
Sources: en.wikipedia.org
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.
It is shorter than the native hormone and carries a cyclic constraint that improves stability. These changes raise receptor potency and slow breakdown relative to the naturally occurring peptide.
Published accounts date its development to the 1980s, when researchers were generating analogues of melanocyte-stimulating hormone. That work aimed to produce more stable compounds for studying pigmentation biology.
No regulatory agency has authorised melanotan-2 as a medicine for any indication. It circulates mainly as a research chemical or through unregulated channels. As a result, identity, purity and content are not independently guaranteed.