Everything below concerns alpha-MSH analogue. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-06-09. Where a claim depends on a specific study, the study is described rather than over-claimed.
Research interest has centred on photoprotection and pigmentation, with a smaller body of work on appetite and sexual function. Published human data remain limited to small, frequently uncontrolled studies, and the compound has never received marketing approval from a national medicines regulator. Most laboratory work treats it as a pharmacological tool for probing melanocortin signalling in cell culture or animal models. Whether pigmentation changes observed in people translate into measurable protection against ultraviolet-induced DNA damage remains an open question.
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-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controlled human data on melanotan-2 remain sparse, and much of what circulates online derives from small studies or unpublished reports.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-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 |
|---|---|---|
| Common synonyms | Melanotan II; MT-II; N-acetyl-norleucyl-cyclo[Asp-His-D-Phe-Arg-Trp-Lys] amide | Naming follows peptide convention; the numeral distinguishes it from melanotan-1 |
| Molecular formula | C50H69N15O9 | Includes the lactam bridge; no counter-ion assumed |
| Monoisotopic mass | 1023.53 Da | Free base; salts and counter-ions shift the observed value |
| Appearance | White to off-white lyophilised powder | Batch-to-batch colour variation is not itself proof of impurity |
| Typical analytical method | RP-HPLC purity determination with ESI-MS identity confirmation | Retention time alone does not establish sequence identity |
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.
Outside regulated medicine, melanotan II circulates through online vendors as a research chemical, often marketed for tanning. Products sold this way vary widely in purity, concentration, and labeling accuracy, and independent testing has documented discrepancies. Published reports describe both pigment effects and adverse reactions, including nausea, flushing, and darkening of existing moles. Long-term safety data are sparse, and no large controlled trial has established a risk profile. Questions about cumulative effects on melanocytes remain unresolved in the literature.
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.
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.
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.
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.
Regulatory treatment varies between countries. Several national medicines agencies have classified the peptide as unapproved, and customs authorities in some jurisdictions seize shipments on that basis. A few jurisdictions channel supply through prescription-only frameworks that do not list the substance by name. Because the material circulates mainly through online vendors, composition and purity are rarely verified before sale. Surveys of unapproved peptide products have reported labels that did not match measured content in a substantial fraction of samples.
Melanotan II is a synthetic cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone, a naturally occurring peptide involved in pigmentation signalling. Its structure substitutes a lactam bridge between side chains to increase stability relative to the native hormone. The compound is also known by the shorthand MT-II and by several non-proprietary synonyms used in research catalogues. It is not an approved therapeutic product in any major jurisdiction; material sold under this name is typically offered as a laboratory reagent rather than as a medicine.
Current evidence suggests that dinosaur average size varied through the Triassic, Early Jurassic, Late Jurassic and Cretaceous. Predatory theropod dinosaurs, which occupied most terrestrial carnivore niches during the Mesozoic, most often fall into the 100-to-1,000 kg (220-to-2,200 lb) category when sorted by estimated weight into categories based on order of magnitude, whereas recent predatory carnivoran mammals peak in the 10-to-100 kg (22-to-220 lb) category. The mode of Mesozoic dinosaur body masses is between 1 and 10 metric tons (1.1 and 11.0 short tons). This contrasts sharply with the average size of Cenozoic mammals, estimated by the National Museum of Natural History as about 2 to 5 kg (4.4 to 11.0 lb). The sauropods were the largest and heaviest dinosaurs. For much of the dinosaur era, the smallest sauropods were larger than anything else in their habitat, and the largest was an order of magnitude more massive than anything else that has since walked the Earth. Giant prehistoric mammals such as Paraceratherium (the largest land mammal ever) were dwarfed by the giant sauropods, and only modern whales approach or surpass them in size. There are several proposed advantages for the large size of sauropods, including protection from predation, reduction of energy use, and longevity, but it may be that the most important advantage was dietary. Large animals are more efficient at digestion than small animals, because food spends more time in their digestive systems. This also permits them to subsist on food with lower nutritive value than smaller animals.
SIMS and FAB are quite similar. SIMS uses an ion beam, usually Ar+ or Cs+. FAB uses a neutral atom beam, usually Ar or Xe. For SIMS and FAB, if the matrix compound is more acidic than the analyte, then predominantly (M + H)+ forms formed, and conversely (M − H)−. Also possibly forming (M + Na)+, (M + K)+, etc, if the matrix is contaminated incidentally (adventitiously) by sodium, potassium, etc. Typical matrix materials include glycerol, thioglycerol, 3-nitrobenzyl alcohol, diethanolamine, triethanolamine, and dithiothreitol-dithioerythritol mixture. They are usually used to analyze polypeptides and oligonucleotides up to 20 kDa. MALDE uses a photon beam, usually the soft-UV 337 nm nitrogen laser. It can also use an infrared (IR) laser for direct analysis of samples contained in gels or thin-layer chromatography (TLC) plates. MALDE can analyze small polymers (~1 kDa), to oligosaccharides, oligonucleotides and polypeptides, antibodies, up to small proteins (~300 kDa). It is highly sensitive, requiring only femtomoles of sample. Desorption/ionization on silicon (DIOS) is similar to MALDE, but without the matrix. The sample is deposited directly on a nanostructured (porous silicon) surface and the sample desorbed directly from the nanostructured surface through the adsorption of laser light energy. DIOS has been used to analyze organic molecules, metabolites, biomolecules and peptides, and, ultimately, to image tissues and cells.
Druze, like some Christians, believe that Elijah came back as John the Baptist, or as Saint George, since they belief in reincarnation and the transmigration of the soul, Druze believe that El Khidr and John the Baptist are one and the same. Saint George is described as a prophetic figure in Druze sources; and in some sources he is identified with Elijah or Mar Elias, and in others as al-Khidr. Druze believe that Elijah came back as John the Baptist and as Saint George, and the Druze version of the story of al-khidr was syncretized with the story of Saint George and the Dragon. The shrine of al-Khidr is located in the village of Kafr Yasif near the city of Acre on the Mediterranean coast. It is considered one of the most famous shrines in Druze religion. The prophet's name is "Sidna Abu Ibrahim" and he is nicknamed Nabi Al-Khidr (the Green One). Al-Khidr is identified with Elijah the prophet and, according to Druze belief, is one of the founders of their religion. The nickname El-Khidr (the Green One) comes from the belief that his memory will always be fresh like a green plant. Ziyarat al-Nabi al-Khidr is an Israeli Druze festival called Ziyara celebrated on 25 January which is officially recognized in Israel as a public holiday for Druzes, the celebration starts on 24 January and concludes on 25 January, with many religious leaders from all the religions in Israel, and also political leaders (occasionally also the PM), coming to congratulate the Israeli Druze community during their festivities at the Maqam Al-Khidr in Kafr Yasif.
A ribosome is a large complex of RNA and protein molecules considered as a membrane-less organelle when freely found in the cytosol, or as a membrane-bound organelle when located in the rough type of endoplasmic reticulum. They each consist of two subunits, one larger than the other, and act as an assembly line where messenger RNA from the nucleus is used to synthesise proteins from amino acids.
The two substrates of this enzyme are cinnamyl alcohol and oxidised nicotinamide adenine dinucleotide phosphate (NADP+). Its products are cinnamaldehyde, reduced NADPH, and a proton. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is cinnamyl-alcohol:NADP+ oxidoreductase. Other names in common use include cinnamyl alcohol dehydrogenase, and CAD. This enzyme participates in phenylpropanoid biosynthesis.
Sources: en.wikipedia.org
A lack of accurate data makes it difficult to document numerically the extent of the human losses suffered by Polish citizens during World War II. Additionally, many assertions made in the past must be considered suspect due to flawed methodology and a desire to promote certain political agendas. The last available enumeration of ethnic Poles and the large ethnic minorities is the Polish census of 1931. Exact population figures for 1939 are therefore not known. According to the United States Holocaust Memorial Museum, at least 3 million Polish Jews and at least 1.9 million non-Jewish Polish civilians were killed. According to the historians Brzoza and Sowa, about 2 million ethnic Poles were killed, but it is not known, even approximately, how many Polish citizens of other ethnicities perished, including Ukrainians, Belarusians, and Germans. Millions of Polish citizens were deported to Germany for forced labor or to German extermination camps such as Treblinka, Auschwitz and Sobibór. Nazi Germany intended to exterminate the Jews completely, in actions that have come to be described collectively as the Holocaust. The Poles were to be expelled from areas controlled by Nazi Germany through a process of resettlement that started in 1939. Such Nazi operations matured into a plan known as the Generalplan Ost that amounted to displacement, enslavement and partial extermination of the Slavic people and was expected to be completed within 15 years.
Mexico's tequila protection interests were prominent during the Chinese accession negotiations to the World Trade Organization. In accordance with WTO accession regulations, in order to gain considerations for WTO membership, China had to sign bilateral agreements with all existing members, including Mexico. Since China has a climatic condition suitable for blue agave plants, Mexico was worried about rival pseudo tequilas from China. The Mexican authorities took the opportunity of the bilateral negotiations with China to ensure that the latter accepted tequila as a geographically indicated product.
=== Cockcroft–Gault formula === A commonly used surrogate marker for the estimation of creatinine clearance is the Cockcroft–Gault (CG) formula, which in turn estimates GFR in mL/min: It is named after the scientists, the asthmologist Donald William Cockcroft (b. 1946) and the nephrologist Matthew Henry Gault (1925–2003), who first published the formula in 1976, and it employs serum creatinine measurements and a patient's weight to predict the creatinine clearance. The formula, as originally published, is:
== Sultanate and Kingdom of Egypt == The Order was established in 1915 by Sultan Hussein Kamel of Egypt for award to persons who had rendered useful service to the country. It ranked beneath the Order of Ismail and was frequently awarded to British officers and officials serving in Egypt, as well as distinguished Egyptian citizens.The order comprised five classes:
Sources: en.wikipedia.org
It is a synthetic cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone, containing seven amino acids with a lactam ring and a D-configured phenylalanine residue. It is supplied as a lyophilised powder for laboratory research.
The natural hormone is a linear tridecapeptide that is rapidly degraded in circulation. Melanotan-2 is shortened, cyclised, N-terminally acetylated, and carries a D-amino acid substitution, all of which slow enzymatic breakdown.
No national medicines regulator has approved melanotan-2 for therapeutic or cosmetic use. In several jurisdictions it is treated as an unapproved prescription medicine, and its legal classification differs from country to country.
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.