Everything below concerns reversed-phase HPLC. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2025-09-15. Numbers and descriptions here follow the published literature rather than marketing material.
Melanotan-2, also written Melanotan II, is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone. Its sequence is Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, and the lactam bridge between the aspartate and lysine side chains constrains the peptide into a ring. This structural change increases receptor affinity and metabolic stability relative to the native hormone. The compound was created in the 1980s as a research tool for studying pigmentation biology.
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.
Identity and purity are assessed with chromatographic and mass spectrometric techniques. Reversed-phase high-performance liquid chromatography separates the target peptide from related impurities and degradation products, and the resulting retention time is compared against a reference standard. Mass spectrometry, often coupled to liquid chromatography, confirms molecular mass. Amino acid analysis or peptide mapping can provide additional sequence-level confirmation when required. Results are only as reliable as the reference materials used alongside them.
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.
| Property | Value | Notes |
|---|---|---|
| Compound class | Synthetic cyclic heptapeptide | Alpha-MSH analogue containing a D-phenylalanine residue |
| Molecular formula | C50H69N15O9 | Average molecular mass approximately 1024.2 g/mol |
| Appearance | White to off-white lyophilised powder | Normally supplied as a freeze-dried solid in a sealed vial |
| Solubility | Freely soluble in water and polar solvents | Dissolves readily in aqueous buffers and in alcohol-water mixtures |
| Receptor targets | MC1R, MC3R, MC4R, MC5R | Acts as a non-selective melanocortin receptor agonist |
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.
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.
Lyophilised peptide powder is comparatively stable when kept dry, cold and protected from light. Once dissolved, the molecule is exposed to hydrolysis, oxidation and microbial growth, and degradation accelerates at higher temperatures and in alkaline solution. Repeated freeze-thaw cycles concentrate solutes and promote aggregation. Handling guidance for research peptides commonly clusters around freezer temperatures for powder and short refrigerated use for reconstituted solutions, with pH control and sterile technique applied throughout.
Verification of a purchased sample requires documentation linking a batch to a certificate of analysis, and that document should be read for the methods used rather than the headline purity figure. A single chromatographic percentage does not establish identity. Independent laboratories can perform identity and content assays, but no such test establishes that a product is suitable for human use. Claims about efficacy rest largely on small, early studies rather than on replicated controlled trials, and that gap remains open.
Fire (火) = Heart (心; xīn) and Small Intestine (小腸; xiaǒcháng) (and, secondarily, Sānjiaō [三焦, "Triple Burner"] and Pericardium [心包; xīnbaò]) Earth (土) = Spleen (脾; pí) and Stomach (胃; weì) Metal (金) = Lung (肺; feì) and Large Intestine (大腸; dàcháng) Water (水) = Kidney (腎; shèn) and Bladder (膀胱; pángguāng) Wood (木) = Liver (肝; gān) and Gallbladder (膽; dān) The zàng-fǔ are also connected to the twelve standard meridians – each yang meridian is attached to a fǔ organ, and five of the yin meridians are attached to a zàng. As there are only five zàng but six yin meridians, the sixth is assigned to the Pericardium, a peculiar entity almost similar to the Heart zàng.
To achieve Type I, humanity must be able to communicate with the rest of the world and to focus on several areas: building infrastructure to facilitate communication and cooperation, education, research and development, and innovation, as well as building strong ties between diasporas and their countries of origin, and between migrants and non-migrants. If development fails, it is likely that the world will not be able to achieve Type II. If these areas do not develop, Kaku predicts that humanity will sink into the "abyss": an advanced civilization must grow faster than the frequency of occurrence of extinction-level cosmic catastrophes, such as comet or asteroid impacts. A Type I civilization should also be able to master space travel to deflect threatening objects. It would also have to anticipate the onset of ice ages and modify the climate long before they occur to avoid them. In addition, in his books Hyperspace and Parallel Worlds, Michio Kaku has discussed a Type IV civilization that could harness "extragalactic" energy sources such as dark energy.
== Treatment == Surgery is the most common form of the treatment for most sarcomas that have not spread to other parts of the body, and for most sarcomas, surgery is the only curative treatment. Limb-sparing surgery, as opposed to amputation, can now be used to save the limbs of patients in at least 90% of extremity (arm or leg) sarcoma cases. Additional treatments, including chemotherapy, radiation therapy (also called "radiotherapy"), which includes proton therapy, may be administered before surgery (called "neoadjuvant" chemotherapy or radiotherapy) or after surgery (called "adjuvant" chemotherapy or radiotherapy). The use of neoadjuvant or adjuvant chemotherapy and radiotherapy significantly improves the prognosis for many sarcoma patients. Treatment can be a long and arduous process, lasting about a year for many patients.
Einsteinium is produced in minute quantities by bombarding lighter actinides with neutrons in dedicated high-flux nuclear reactors. The world's major irradiation sources are the 85-megawatt High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL), Tennessee, U.S., and the SM-2 loop reactor at the Research Institute of Atomic Reactors (NIIAR) in Dimitrovgrad, Russia, which are both dedicated to the production of transcurium (Z>96) elements. These facilities have similar power and flux levels, and are expected to have comparable production capacities for transcurium elements, though the quantities produced at NIIAR are not widely reported. In a "typical processing campaign" at ORNL, tens of grams of curium are irradiated to produce decigram quantities of californium, milligrams of berkelium (249Bk) and einsteinium and picograms of fermium. The first microscopic sample of 253Es weighing about 10pr nanograms was prepared in 1961 at HFIR. A special magnetic balance was designed to estimate its weight. Larger batches were produced later starting from several kilograms of plutonium with the einsteinium yields (mostly 253Es) of 0.48 milligram in 1967–1970, 3.2 milligrams in 1971–1973, followed by steady production of about 3 milligrams per year between 1974 and 1978. These quantities however refer to the integral amount in the target right after irradiation. Subsequent separation procedures reduced the amount of isotopically pure einsteinium roughly tenfold.
Sources: en.wikipedia.org
Larry Hama took over Wolverine's solo series in 1990, and exerted a major influence on how Wolverine was depicted throughout the X-Men family of publications during his run. Hama commented that he "considered the Chris Claremont, Frank Miller, and Barry Windsor-Smith [Wolverine] stories to be canon" and "pretty much ignored everything else." From 1990 to 1992, the series was usually illustrated by Marc Silvestri, who contributed to the character's rising popularity; his work on Wolverine also established him as a star artist in the industry. In issues #48-50 (November 1991-January 1992), Hama delved into Wolverine's mysterious past in the Weapon X program, which was often highly convoluted and unreliable due to the false memories implanted by the program's designers. In 1992, he revisited the Japanese setting and characters of Claremont's and Miller's earlier limited series, ending the story with the poisoning of Mariko Yashida, Logan's lover, and her mercy killing at the hands of Wolverine. During the Fatal Attractions storyline, in X-Men #25 (October 1993), the adamantium in Wolverine's body is ripped out by Magneto, using his magnetic abilities. Writers Fabian Nicieza and Scott Lobdell were inspired by a suggestion of another Marvel writer, Peter David. The story arc reveals that Wolverine has natural bone claws, in contrast to previously established narrative continuity that his claws were entirely bionic. Wolverine himself is confused by this realization, and his healing factor is also greatly weakened by recovery from this extraordinary injury.
==== Metabolism ==== In terms of metabolism, methenamine is hydrolyzed to form formaldehyde and ammonium in acidic urine (pH < 6). More specifically, a single molecule of methenamine decomposes into six equivalents of formaldehyde and four ammonia molecules. The drug may be degraded 10 to 30% in the acidic environment of the stomach prior to absorption. This can be avoided with enteric coated tablets. In terms of pH, there is minimal hydrolysis at a pH of 7.4, 6% at a pH of 6, and 20% at a pH of 5. The hydrolysis of methenamine occurs slowly and gradually, with approximately 3 hours required for 90% decomposition into formaldehyde. As breakdown of methenamine only occurs in acidic environments like the bladder and stomach, the activation of methenamine into formaldehyde in the body is tissue-selective. Following its formation, formaldehyde is rapidly metabolized into formic acid (formate) in the body.
==== Other health effects ==== Breastfeeding may reduce the risk of necrotizing enterocolitis (NEC) in premature babies. Breastfeeding or introduction of gluten while breastfeeding does not protect against celiac disease among at-risk children. Breast milk of healthy human mothers who eat gluten-containing foods presents high levels of non-degraded gliadin (the main gluten protein). Early introduction of traces of gluten in babies to potentially induce tolerance does not reduce the risk of developing celiac disease. Delaying the introduction of gluten does not prevent, but is associated with a delayed onset of the disease. About 14 to 19 percent of leukemia cases may be prevented by breastfeeding for six months or longer. However, breastfeeding is also the primary cause of adult T-cell leukemia/lymphoma, as the HTLV-1 virus is transmitted through breastmilk. Breastfeeding is associated with a lower chance of developing diabetes mellitus type 1 in the offspring. Breastfed babies also appear to have a lower likelihood of developing diabetes mellitus type 2 later in life. Breastfeeding may decrease the risk of cardiovascular disease in later life, as indicated by lower cholesterol and C-reactive protein levels in breastfed adult women. Breastfed infants have somewhat lower blood pressure later in life, but it is unclear how much practical benefit this provides. A 1998 study suggested that breastfed babies have a better chance of good dental health than formula-fed infants because of the developmental effects of breastfeeding on the oral cavity and airway.
Ion yield is typically estimated to range from 10−4 to 10−7, with some experiments hinting to even lower yields of 10−9. The issue of low ion yields had been addressed, already shortly after introduction of MALDI by various attempts, including post-ionization utilizing a second laser. Most of these attempts showed only limited success, with low signal increases. This might be attributed to the fact that axial time-of-flight instruments were used, which operate at pressures in the source region of 10−5 to 10−6, which results in rapid plume expansion with particle velocities of up to 1000 m/s. In 2015, successful laser post-ionization was reported, using a modified MALDI source operated at an elevated pressure of ~3 mbar coupled to an orthogonal time-of-flight mass analyzer, and employing a wavelength-tunable post-ionization laser, operated at wavelength from 260 nm to 280 nm, below the two-photon ionization threshold of the matrices used, which elevated ion yields of several lipids and small molecules by up to three orders of magnitude. This approach, called MALDI-2, due to the second laser, and the second MALDI-like ionization process, was afterwards adopted for other mass spectrometers, all equipped with sources operating in the low mbar range.
During the 2025 legislative session, Moore introduced the Excellence in Maryland Public Schools Act, which proposed temporary pauses on plans under the Blueprint to gradually give teachers more "collaborative time" to work on professional development and planning outside of the classroom, reduce funding for programs to support students learning English, and freeze funding for community schools for two years. These proposed changes would cut nearly one-fifth of new funding provided under the Blueprint reforms and have the most impact on students living in poverty and immigrant students. Moore's proposed Blueprint reforms were largely rejected by lawmakers, who amended Moore's bill to reinstate funding for community schools and students learning English, but implemented a three-year delay on collaborative time implementation plans. Moore signed the Excellence in Maryland Public Schools Act into law in May 2025.
Sources: en.wikipedia.org
=== Integrin binding === CCN1 binds directly to various integrin receptors in a cell type-dependent manner, including integrin αvβ3 in endothelial cells, α6β1 and heparan sulfate proteoglycans (HSPGs) in fibroblasts and smooth muscle cells αIIbβ3 in activated platelets, αMβ2 in monocytes and macrophages, and αDβ2 in macrophage foam cells. Where examined, syndecan-4 has been identified as the HSPG critical for CCN1 functions. The CCN1 binding sites for some of these integrins have been mapped (Figure 1). Due to the cell type specificity of integrin expression, CCN1 acts through distinct integrins to mediate specific functions in different types of cells. For example, CCN1 induces angiogenic functions in endothelial cells through αvβ3, and in fibroblasts promotes cellular senescence and enables TNFα to induce apoptosis through binding to α6β1-HSPGs. However, CCN1 supports cell adhesion through all of the integrins identified above.
=== Support for retail reforms === In a pan-Indian survey conducted over the weekend of 3 December 2011, overwhelming majority of consumers and farmers in and around ten major cities across the country support the retail reforms. Over 90 per cent of consumers said FDI in retail will bring down prices and offer a wider choice of goods. Nearly 78 per cent of farmers said they will get better prices for their produce from multi-format stores. Over 75 per cent of the traders claimed their marketing resources will continue to be needed to push sales through multiple channels, but they may have to accept lower margins for greater volumes. A study in India on title 'Foreign Direct Investment In Indian Retail Sector: Drawing lessons from the international experience', concluded that the entry of FDI in multi brand retail in India can be growth enhancing only if proper safeguards are in place and the market environment is regulated. Firstly, the resources should be dedicated for a comprehensive study of retail and its related industries. Secondly, the number of big retail outlets in a particular city should be decided on the basis of population criterion and the employment level of local youth in the retail business. Thirdly, the format of these retail chains should also be regulated as is done in Malaysian case. They should not be in the form of neighborhood convenience store and there should be minimum and maximum limit of the size of these stores.
=== Elsewhere === Generally, the firmer styles of tofu are used for kebabs, mock meats, and dishes requiring a consistency that holds together, while the softer styles can be used for desserts, soups, shakes, and sauces. Some people enjoy tofu made and prepared with chocolate and making it into pies and mousse along with other tofu desserts. This came about due to vegans and vegetarians avoiding the usage of items such as milk and eggs. Firm Western tofu types can be barbecued since they hold together on a barbecue grill. These types are usually marinated overnight as the marinade does not easily penetrate the entire block of tofu. (Techniques to increase the penetration of marinades include stabbing repeatedly with a fork or pressing out the initial water content either by hand or with a tofu press prior to marinating. Before pressing the tofu, it is sometimes frozen and thawed in order of creating a more porous texture, often compared to a sponge. This texture does not only help release the initial water content, but also allows for an altered mouthfeel and more absorbent structure. Typically, the tofu is frozen and thawed once, although some culinary experts recommend executing this technique twice for a stronger effect.) Grated firm Western tofu is sometimes used in conjunction with textured vegetable protein (TVP) as a meat substitute. Softer tofus are sometimes used as a dairy-free or low-calorie filler. Silken tofu may be used to replace cheese in certain dishes, such as lasagna.
=== Selected publications === 2023, The Information Theory of Aging, Nature Aging 2023, Chemically induced reprogramming to reverse cellular aging, Aging 2023, Loss of epigenetic information as a cause of mammalian aging, Cell 2021, The economic value of targeting aging, Nature Aging 2020, Reprogramming to recover youthful epigenetic information and restore vision, Nature 2008, SIRT1 redistribution on chromatin promotes genomic stability but alters gene expression during aging, Cell
Sources: en.wikipedia.org
No. It is a laboratory-made peptide, while the natural hormone is alpha-melanocyte-stimulating hormone, a longer peptide produced by the pituitary gland and by skin cells. Melanotan-2 mimics only a short active region of that hormone and contains non-natural residues such as D-phenylalanine.
No approved regulatory indication exists in major markets. An approval exists for a different peptide, afamelanotide, which is used for a rare photosensitivity disorder called erythropoietic protoporphyria. Melanotan-2 itself remains a research compound with no cleared clinical role.
Melanocortin-1 receptors on melanocytes are the receptor most closely linked to pigment production. The peptide is not selective, however, and also activates melanocortin-3, melanocortin-4, and melanocortin-5 receptors. That lack of selectivity is the usual explanation offered for both its range of observed effects and its off-target effects.
Laboratory confirmation typically combines retention time matching on a chromatographic system with mass measurement. A reference standard of known identity is needed for a meaningful comparison. Sequence-level techniques can add further confirmation.