Everything below concerns cyclic heptapeptide. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-07-19. 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.
| 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.
VfB Leipzig were immediately successful at their chosen sport and made their way to the first German national championship final held in 1903. Their opponents were DFC Prag, a German-Jewish side from Prague, which was then part of Austria-Hungary. The DFB had invited "German" clubs of this sort from other countries to boost numbers in their new national association. DFC Prag had made their way to the final under circumstances that had allowed them to avoid playing a single playoff match, while VfB Leipzig had come through some hard-fought matches. Arriving in Hamburg for the match, the heavily favoured Pragers took themselves off on an ill-advised pub crawl the night before the contest and so arrived on the pitch in less than ideal match shape. The contest was delayed by half an hour as officials scrambled to find a football that was in good condition. The host, FC 93 Altona Hamburg, provided a new ball, and 11 minutes in, DFC Prag scored the first goal. At the end of the first half, the score stood at 1–1, but VfB Leipzig then pulled away to emerge as the first winners of the Viktoria Meisterschaftstrophäe ("Victoria Championship Trophy"), representative of German football supremacy, on the strength of a decisive 7–2 victory. VfB Leipzig played themselves into another final appearance in 1904, but the match was never contested. A protest by FV Karlsruhe over their disputed semi-final with Britannia Berlin was never resolved, and the DFB called off the final only hours before its scheduled start. There would be no champion that year.
The toxicity may also result from non-combustible sources such as the one released from anaerobic fermentation of food grains and anaerobic digestion of biodegradable waste. The World Health Organization (WHO) developed a global recommendation limiting exposures to less than 20 parts per billion for chronic exposure and value less 100 ppb for one hour for acute exposure, using nitrogen dioxide as a marker for other pollutants from fuel combustion. There is a significant association between indoor NO2 levels and increased respiratory symptoms such as wheeze, chest tightness and severity of infections among children with asthma. Historically, some cities in the United States including Chicago and Los Angeles have higher levels of nitrogen dioxide than the EPA maximum exposure limits of 100 ppb for a one-hour exposure and less than 53 ppb for chronic exposure.
=== Themes === Murphy has described The Beauty as a commentary on "Ozempic culture" and the broader social fixation on rapid, drug-assisted physical transformation. In promotional interviews, Murphy framed the story around the question of how much people would be willing to sacrifice in pursuit of beauty, positioning the series as an extension of themes explored in his earlier work Nip/Tuck while emphasizing its science fiction and body-horror elements.
Sources: en.wikipedia.org
== Coupling with THG microscopy == Third-Harmonic Generation (THG) microscopy can be complementary to SHG microscopy, as it is sensitive to the transverse interfaces, and to the 3rd order nonlinear susceptibility
The term reticulin was coined in 1892 by M. Siegfried. Today, the term reticulin or reticular fiber is restricted to referring to fibers composed of type III collagen. However, during the pre-molecular era, there was confusion in the use of the term reticulin, which was used to describe two structures:
However, for every number of nucleons from 94 to 102, there is already at least one stable nuclide of either molybdenum (Z = 42) or ruthenium (Z = 44), and the Mattauch isobar rule states that two adjacent isobars cannot both be stable. For the isotopes with odd numbers of nucleons, this immediately rules out a stable isotope of technetium, since there can be only one stable nuclide with a fixed odd number of nucleons. For the isotopes with an even number of nucleons, since technetium has an odd number of protons, any isotope must also have an odd number of neutrons. In such a case, the presence of a stable nuclide having the same number of nucleons and an even number of protons rules out the possibility of a stable nucleus.
Sources: en.wikipedia.org
Le Havre's festival calendar is punctuated by a wide range of events. In spring a Children's Book Festival was recently created. In May there is the Fest Yves, a Breton festival in the Saint-François district. On the beach of Le Havre and Sainte-Adresse there is a jazz festival called Dixie Days in June. In July, detective novels are featured in the Polar room at the Beach hosted by The Black Anchors. Between the latter also in the context of Z'Estivales is an event offering many shows of street art throughout the summer supplemented by the festival of world music MoZaïques at the fort of Sainte-Adresse in August since 2010. In mid-August there is a Flower parade which passes through the streets of the central city. In the first weekend of September the marine element is highlighted in the Festival of the Sea. This is a race between Le Havre and Bahia in Brazil. Also every November there is a fair held in the Docks Café. The Autumn Festival in Normandy, organized by the departments of Seine-Maritime and Eure, and the Region of Normandy, runs from September to November and offers numerous concerts throughout the region as well as theatre performances and dance. In late October, since 2009, there is rock music festival which has been at the fort of Tourneville since the moving of the Papa's Production association site there. The West Park Festival, after its inauguration in 2004, has been held in the park of the town hall of Harfleur. Since 1 June 2006 a Biennale of contemporary Art has been organized by the group Partouche.
==== Background ==== Leukocytes, as well as other types of white blood cells, normally form weak and short-lived bonds with other cells via selectin. Coated outside the membrane of leukocytes are microvilli, which have various types of adhesive molecules, including P-selectin glycoprotein ligand-1 (PSGL-1), a glycoprotein that is normally decorated with sulfated sialyl-Lewis x. the sulfated-sialyl-Lewis-x-contained PSGL-1 molecule has the ability to bind to any type of selectin. Leukocytes also exhibit L-selectin that binds to other cells or other leukocytes that contain PSGL-1 molecules.
The Canadian Penning Trap Mass Spectrometer (CPT) is one of the major pieces of experimental equipment that is installed on the ATLAS superconducting heavy-ion linac facility at the Physics Division of the Argonne National Laboratory. It was developed and operated by physicist Guy Savard and a collaboration of other scientists at Argonne, the University of Manitoba, McGill University, Texas A&M University and the State University of New York.
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.