alpha-MSH analogue comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Updated 2025-09-22. Numbers and descriptions here follow the published literature rather than marketing material.
Melanotan II is a synthetic peptide analog modeled on alpha-melanocyte-stimulating hormone, a naturally occurring signaling peptide involved in pigmentation. Its structure is a cyclic heptapeptide containing two non-natural substitutions, norleucine at position four and D-phenylalanine at position seven. These modifications resist enzymatic breakdown and extend the molecule's activity relative to the native hormone. The compound binds melanocortin receptors and is studied mainly as a pharmacological tool rather than a therapeutic product. It has never received approval as a medicine in any major jurisdiction.
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.
Melanotan-2 is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone. Its sequence incorporates a lactam bridge that constrains the peptide into a ring, which increases resistance to enzymatic breakdown relative to the natural hormone. Researchers at the University of Arizona synthesised the compound in the late 1980s and early 1990s while studying pigmentation pathways. It has never received marketing approval from any national medicines regulator. In the scientific literature it is usually described as a laboratory research reagent rather than a therapeutic product.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic cyclic heptapeptide | Belongs to the melanocortin agonist family |
| Key substitutions | Nle4 and D-Phe7 | Improve resistance to enzymatic degradation |
| Molecular formula | C50H69N15O9 | Approximately 1024 g/mol |
| Regulatory status | Not approved as a medicine | Distributed as a research chemical |
| Common synonyms | Melanotan II, MT-II, MT-2 | Spelling varies across sources |
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.
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.
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.
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.
Melanotan II is a synthetic cyclic heptapeptide analog derived from the core sequence of alpha-melanocyte-stimulating hormone. Researchers at the University of Arizona synthesized it during the 1980s while studying pigmentation and appetite signaling. The compound is not an approved medicine in any major jurisdiction and appears mainly in laboratory and research-chemical settings. Its structure incorporates a lactam bridge between side chains, which constrains the ring and slows enzymatic breakdown relative to the natural hormone.
Melanotan II binds several melanocortin receptor subtypes rather than a single target. MC1R on melanocytes drives melanin synthesis, while MC3R and MC4R participate in energy balance, appetite, and sexual response pathways. This lack of selectivity explains why reported effects extend beyond skin darkening. Substitutions at positions four and seven, including norleucine and D-phenylalanine, increase potency and resistance to peptidases. Understanding which receptor mediates which effect remains an active area of investigation.
Published human data come mostly from small, short studies rather than large controlled trials. Reported outcomes include increased skin pigmentation and, in some reports, effects on appetite and libido, but sample sizes are small and follow-up is limited. Whether long-term use produces durable pigment changes or adverse effects is not established. Because products sold outside pharmacies are not standardized, the actual content of any given vial is often unknown. Independent testing of such material is uncommon.
== Analysis == The groups of bioactive compounds present in E. planum are phenolic acids, triterpenoid saponins, flavonoids, coumarins, and essential oils. The wide range of compounds is reflected in the wide range of uses. Qualitative and quantitative determinations of the phenolic acids by reverse phase high-performance liquid chromatography (RP HPLC) show relatively small amounts of rosmarinic, chlorogenic, and caffeic acids in the basal leaves and the roots of intact plants, and greater concentrations in E. planum from in vitro cultures. Qualitative and quantitative analyses of the essential oil compounds performed by gas chromatography with a flame ionization detector linked to a mass spectrometer (GC-FID-MS) show the main components of stalk leaf oil, and rosette leaf oil, as monoterpenes (limonene, and α- and β-pinene), sesquiterpenes, and hydrocarbons. (Z)-Falcarinol was found as the major component of root essential oil.
Francisco Rodríguez, an economist, called on Venezuela's National Assembly to reject the deal, describing it as "predatory" and arguing that transferring Venezuelan oil wealth to the United States was unconstitutional and not in the country's interest, particularly when carried out under the threat of force. Gregory Brew, an energy historian and analyst at the Eurasia Group, expressed skepticism about the agreement, predicting significant opposition to any deal that would give the U.S. government effective control over Venezuelan resources. He compared the arrangement to the early 20th-century control exercised by the Anglo-Persian Oil Company over oil resources in Iraq and Iran, and suggested that for Trump, control over oil appeared to be an objective in itself, with the arrangement carrying colonial overtones. On 31 August, The New York Times reported that the arrangement would give the Defense Department the option to acquire up to 35 per cent of the parent company of Betancourt's firm through a warrant, described by two people familiar with the deal as a penny warrant convertible into shares for as little as one cent. The White House said the same day that the partnership came "all at zero cost to the United States", that the federal government would be guaranteed 20 per cent of the company's output at production cost with the State Department holding a right of first refusal over the remainder, and that the United States would hold a veto over appointments to the company's board, a majority of whose members would have to be American citizens.
They proposed the name Parmotrema chinense, based on the assumption that Osbeck's specimen corresponded to the well-known species Parmotrema perlatum. However, this proposal was not universally adopted due to the lack of valid typification and the name's absence in the literature between 1757 and 1986.
Sources: en.wikipedia.org
==== Iron import in some cancer cells ==== Iron can also enter cells via CD44 in complexes bound to hyaluronic acid during epithelial–mesenchymal transition (EMT). In this process, epithelial cells transform into mesenchymal cells with detachment from the basement membrane, to which they’re normally anchored, paving the way for the newly differentiated motile mesenchymal cells to begin migration away from the epithelial layer. While EMT plays a crucial role in physiological processes like implantation, where it enables the embryo to invade the endometrium to facilitate placental attachment, its dysregulation can also fuel the malignant spread of tumors empowering them to invade surrounding tissues and establish distant colonies (metastasis). Malignant cells often exhibit a heightened demand for iron, fueling their transition towards a more invasive mesenchymal state. This iron is necessary for the expression of mesenchymal genes, like those encoding transforming growth factor beta (TGF-β), crucial for EMT. Notably, iron’s unique ability to catalyze protein and DNA demethylation plays a vital role in this gene expression process. Conventional iron uptake pathways, such as those using the transferrin receptor 1 (TfR1), often prove insufficient to meet these elevated iron demands in cancer cells. As a result, various cytokines and growth factors trigger the upregulation of CD44, a surface molecule capable of internalizing iron bound to the hyaluronan complex.
1 August 2024 Southport stabbing The 17-year-old suspect is named as Axel Rudakubana. He is charged with three counts of murder, ten counts of attempted murder, and one count of possession of a bladed article. As a minor, he could not initially be named; but reporting restrictions on his identity are lifted by Liverpool Crown Court. After being charged, Rudakubana is remanded in custody until a plea hearing on 25 October. Keir Starmer holds a crisis meeting with police chiefs and an emergency press conference in the wake of rioting following the murders. Starmer condemns "far-right hatred" responsible for the unrest, and announces the launch of a national violent disorder programme that will see greater cooperation between police forces to tackle violent disorder, as fears grow of a "summer of unrest" fuelled by misinformation. The Bank of England cuts the UK interest rate from 5.25% to 5%, the first interest rate cut since the start of the COVID-19 pandemic in March 2020. GPs in England vote to take industrial action by working-to-rule over a lack of funding and a decline in care, which could see GP appointments capped at 25 per day. 2 August The BBC reports that Labour has shelved £1.3bn of funding promised by the Conservatives for technology and artificial intelligence (AI) projects, including an exascale supercomputer at Edinburgh University. 2024 Summer Olympics: Team GB secures three gold medals – in rowing, equestrian, and trampoline – bringing their current total to 25 medals: nine golds, eight silvers and eight bronzes.
=== Differential diagnosis === Many other disorders can produce the same type of body characteristics as Marfan syndrome. Genetic testing and evaluating other signs and symptoms can help to differentiate these. The following are some of the disorders that can manifest as "marfanoid":
Sources: en.wikipedia.org
Hard tissue, referring to "normal" calcified tissue, is tissue which is mineralized and has a firm intercellular matrix. The hard tissues of humans are bone, tooth enamel, dentin, and cementum. The term is in contrast to soft tissue.
SNP MP Joanna Cherry demands an apology from colleague Mhairi Black, who suggested some members of the party are "too comfortable" at Westminster. Former Minister Sir Alok Sharma announces he would vote against the Offshore Petroleum Licensing Bill, describing plans to guarantee annual oil and gas licensing rounds as "a total distraction" that reinforce the idea the UK is "not serious" about tackling climate change. British Post Office scandal: Labour Party leader Keir Starmer, who was Director of Public Prosecutions during the scandal, faces questions over why he failed to intervene in the prosecution of innocent sub-postmasters at the time. 9 January Economists say that funding the student loans system in England is expected to cost the government an extra £10 billion a year. British Post Office scandal: Secretary of State for Justice Alex Chalk tells Parliament the UK government is giving "serious consideration" to introducing legislation to quash the convictions of the 700 or so sub post masters who were prosecuted as a result of the Horizon IT scandal. Former Post Office chief executive Paula Vennells announces that she would hand back her CBE after more than a million people signed a petition calling for her to do so. Liberal Democrat leader Ed Davey, who was Post Office minister during the scandal, comes under pressure to return his knighthood. Downing Street confirms that Akshata Murty, the wife of the prime minister, has donated her shares in a childcare company to charity. The shares were at the centre of a conflict-of-interest controversy.
The first production reactor that made 239Pu was the X-10 Graphite Reactor. It went online in 1943 and was built at a facility in Oak Ridge that later became the Oak Ridge National Laboratory. In January 1944, workers laid the foundations for the first chemical separation building, T Plant located in 200-West. Both the T Plant and its sister facility in 200-West, the U Plant, were completed by October. (U Plant was used only for training during the Manhattan Project.) The separation building in 200-East, B Plant, was completed in February 1945. The second facility planned for 200-East was canceled. Nicknamed Queen Mary by the workers who built them, the separation buildings were awesome canyon-like structures 800 feet long, 65 feet wide, and 80 feet high containing forty process pools. The interior had an eerie quality as operators behind seven feet of concrete shielding manipulated remote control equipment by looking through television monitors and periscopes from an upper gallery. Even with massive concrete lids on the process pools, precautions against radiation exposure were necessary and influenced all aspects of plant design. On April 5, 1944, Emilio Segrè at Los Alamos received the first sample of reactor-produced plutonium from Oak Ridge. Within ten days, he discovered that reactor-bred plutonium had a higher concentration of 240Pu than cyclotron-produced plutonium. 240Pu has a high spontaneous fission rate, raising the overall background neutron level of the plutonium sample.
Sources: en.wikipedia.org
It is a synthetic cyclic peptide designed as an analog of alpha-melanocyte-stimulating hormone. It acts on melanocortin receptors and is best known from research into pigmentation. It is not an approved pharmaceutical product.
No regulatory agency has approved it for any indication. It is encountered as a research chemical sold outside pharmaceutical supply chains. Products marketed this way are not subject to the manufacturing and labeling requirements that apply to approved drugs.
Reports describe increased skin pigmentation as well as side effects such as nausea, flushing, and changes to existing moles. Much of the evidence comes from small studies and case reports rather than large trials. The long-term safety profile is therefore uncertain.
It is a synthetic cyclic heptapeptide modelled on alpha-melanocyte-stimulating hormone. A lactam bridge links two side chains, forming a ring that stabilises the molecule against proteolysis. It belongs to the broader melanocortin peptide family.