This is a working overview of mass spectrometry, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2025-12-26 and is reviewed periodically as new material appears.
Published research on the compound remains limited. Much of the human data comes from small, early-stage studies rather than large controlled trials, and several questions about effects and variability between individuals remain open. Investigators have examined receptor activity, pigment pathways, and related physiological responses in laboratory and animal models. Findings from those models do not automatically translate to human outcomes. Reviews frequently note the scarcity of rigorous clinical evidence and call for better-characterized study material.
Because the substance circulates mainly through informal markets, verification is a recurring theme in technical discussion. Independent analyses have found that labeled content and actual content can diverge, and that purity varies between samples. Analytical laboratories use reversed-phase chromatography to separate components and mass spectrometry to confirm identity. Isotope-labeled internal standards improve quantification in complex matrices. Such methods describe what a sample contains but say nothing about its sterility, lawful status, or suitability for any use. Open questions remain about how consistently testing is applied across the supply chain.
The compound was developed in the late 1980s and early 1990s by academic researchers investigating melanocortin signaling and pigmentation. Early work explored whether synthetic analogs could reproduce effects of the natural hormone under controlled conditions. The molecule never advanced through the full regulatory pathway required for approval as a medicine. From the mid-2000s onward it appeared in unregulated consumer markets, often distributed through informal channels. That gap between research origins and commercial availability shapes how the compound is discussed today.
Melanotan-2 is a synthetic peptide designed as an analog of alpha-melanocyte-stimulating hormone, a signaling molecule produced in the pituitary and skin. Its structure is a linear chain of seven amino acids that folds into a ring through an internal lactam bridge joining two side chains. The compound is sometimes written as MT-II or MEL-2 in informal and commercial contexts. It belongs to the melanocortin peptide family, a group of short signaling molecules that share a conserved core sequence recognized by melanocortin receptors.
Two structural changes distinguish the synthetic peptide from the natural hormone. A norleucine residue replaces methionine at one position, and a D-configured phenylalanine replaces the natural L-form at another. Both substitutions slow enzymatic breakdown, which extends the molecule's persistence relative to the parent hormone. The lactam bridge further constrains the backbone into a stable conformation. These features are standard design strategies in peptide chemistry and are not unique to this compound; they appear across many research peptides built for improved stability.
| Property | Value | Notes |
|---|---|---|
| Regulatory status | Not approved as a medicine | No marketing authorization in major jurisdictions |
| Scheduling example | Prescription-only supply in some countries | Handled as an unlicensed medicine where restricted |
| Sports classification | Prohibited peptide | Appears on anti-doping prohibited lists |
| Reported presentation | Lyophilized vial | Nominal content varies between vendors |
| Detection approach | Liquid chromatography–tandem mass spectrometry | Used in anti-doping and forensic testing |
Identification in laboratories relies on reversed-phase liquid chromatography coupled with tandem mass spectrometry, with product-ion spectra compared against a certified reference standard. High-resolution mass spectrometry supplies accurate mass confirmation, and peptide mapping after enzymatic digestion separates melanotan II from closely related analogues. Quantitation of seized material is complicated by unknown counter-ions and residual trifluoroacetate left from purification. Immunoassays raised against alpha-melanocyte-stimulating hormone can cross-react, so chromatographic confirmation is normally required. Urinary detection windows are short, and reported limits of detection differ substantially between laboratories.
Melanotan II holds no marketing authorisation from the Food and Drug Administration, the European Medicines Agency, the UK Medicines and Healthcare products Regulatory Agency or Australia's Therapeutic Goods Administration. Products sold under that name are treated as unapproved new drugs, and their sale or import is prohibited in several jurisdictions. Other countries classify the peptide as a prescription-only medicine or place it among controlled substances, so the legal position changes with the destination market. No pharmacopoeial monograph supplies an official specification, because the material is not a licensed pharmaceutical. Consequently, products offered online are not manufactured to a shared public standard.
Published pharmacokinetic information is limited and comes mainly from small studies rather than registrational trials. Plasma half-life is usually described as short, on the order of tens of minutes, followed by rapid tissue distribution and clearance of the intact peptide. Metabolites and low concentrations of parent compound have been reported in urine, a detail relevant to anti-doping and forensic testing. Whether repeated exposure changes receptor sensitivity or clearance over time remains an open question. Values differ noticeably between analytical assays, so published numbers should be read as approximate rather than definitive.
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.
The class B metallo-β-lactamases (MBLs) are found largely in gram-negative bacteria and environmental bacteria. The subclasses of MBL enzymes are B1, B2, and B3. MBLs have diverse enzymatic functions and have the ability to hydrolyze β-lactam antibiotics. The class D β-lactamases (OXA), which hydrolyze oxacillin, provide a good example of the variety of mechanisms that can be used to transfer resistance. The blaOXA genes which encode OXA β-lactamases are found on both chromosomes and plasmids, and they have their natural reservoir in environmental bacteria and deep-sea microflora. Insertions in the vicinity of these genes have been shown to increase the strength of their promoters and increase resistance. Because of these characteristics, a wide geographic dissemination of OXA carbapenemase resistance in particular has occurred. The facilitated spread of carbapenem resistance appears to have multiple origins and repeated introduction into the UK of bacteria with the blaOXA-48 gene via horizontal transfer of similar plasmids to pOXA-48a.
== External links == "Bombesin Receptors: BB2". IUPHAR Database of Receptors and Ion Channels. International Union of Basic and Clinical Pharmacology. Archived from the original on 2016-03-03. Retrieved 2007-10-25. IUPHAR GPCR Database - BB2 receptor Archived 2016-03-03 at the Wayback Machine Receptors,+Bombesin at the U.S. National Library of Medicine Medical Subject Headings (MeSH) This article incorporates text from the United States National Library of Medicine, which is in the public domain.
The history of anatomy is characterized by a progressive understanding of the functions of the organs and structures of the human body. Methods have also improved dramatically, advancing from the examination of animals by dissection of carcasses and cadavers (corpses) to 20th-century medical imaging techniques, including X-ray, ultrasound, and magnetic resonance imaging.
The cacao tree was domesticated as early as 5300 BP in South America, in present-day southeast Ecuador, by the Mayo-Chinchipe culture, before it was introduced to Mesoamerica. It is unknown when chocolate was first consumed as opposed to other cacao-based drinks, and there is evidence the Olmecs, the earliest known major Mesoamerican civilization, fermented the sweet pulp surrounding the cacao beans into an alcoholic beverage. Chocolate was extremely important to several Mesoamerican societies, and cacao was considered a gift from the gods by the Mayans and the Aztecs. The cocoa bean was used as a currency across civilizations and was used in ceremonies, as a tribute to leaders and gods and as a medicine. Chocolate in Mesoamerica was a bitter drink, flavored with additives such as vanilla, earflower and chili, and was capped with a dark brown foam created by pouring the liquid from a height between containers. Spanish conquistador Hernán Cortés may have been the first European to encounter chocolate when he observed it in the court of Moctezuma II in 1520. It proved to be an acquired taste, and it took until 1585 for the first official recording of a shipment of cocoa beans to Europe. Chocolate was believed to be an aphrodisiac and medicine, and spread across Europe in the 17th century, sweetened, served warm and flavored with familiar spices. Religious orders played a significant role in its dissemination.
== Causes == Gynecomastia is thought to be caused by an altered ratio of estrogens to androgens mediated by an increase in estrogen action, a decrease in androgen action, or a combination of these two factors. Estrogen and androgens have opposing actions on breast tissue: estrogens stimulate proliferation while androgens inhibit proliferation. The cause of gynecomastia is unknown in around 25% of cases. Known causes can be physiologic (occurring normally) or non-physiologic due to underlying pathologies such as drug use, chronic disease, tumors, or malnutrition.
Sources: en.wikipedia.org
Important musical rhythms of the Andean Region are the danza (dance of Andean folklore arising from the transformation of the European contredance), the bambuco (it is played with guitar, tiple and mandolin, the rhythm is danced by couples), the pasillo (a rhythm inspired by the Austrian waltz and the Colombian "danza", the lyrics have been composed by well-known poets), the guabina (the tiple, the bandola and the requinto are the basic instruments), the sanjuanero (it originated in Tolima and Huila Departments, the rhythm is joyful and fast). Apart from these traditional rhythms, salsa music has spread throughout the country, and the city of Cali is considered by many salsa singers to be 'The New Salsa Capital of the World'. The instruments that distinguish the music of the Eastern Plains are the harp, the cuatro (a type of four-stringed guitar) and maracas. Important rhythms of this region are the joropo (a fast rhythm and there is also tapping as a result of its flamenco ancestry) and the galeron (it is heard a lot while cowboys are working). The music of the Amazon region is strongly influenced by the indigenous religious practices. Some of the musical instruments used are the manguaré (a musical instrument of ceremonial type, consisting of a pair of large cylindrical drums), the quena (melodic instrument), the rondador, the congas, bells, and different types of flutes. The music of the Archipelago of San Andrés, Providencia and Santa Catalina is usually accompanied by a mandolin, a tub-bass, a jawbone, a guitar and maracas.
In steady state, Grx2 forms dimers to coordinate iron-sulfur clusters, which in turn inactivate Grx2's activity by sequestering the active-site cysteines. During oxidative stress, the dimers separate into iron-free active monomers, which restore Grx2's activity.
Healthcare providers may recommend lifelong heart-healthy lifestyle choices. These choices included a heart-healthy eating plan, physical activity, quitting smoking, improved sleep hygiene, weight loss, blood pressure control, cholesterol control, blood pressure control, and stress management. Some medications may be prescribed to allow the blood vessels to widen and help the heart pump include ACE inhibitors, beta blockers, calcium channel blockers, nitrates, and Ranolazine. Some medications may be prescribed to manage cholesterol include statins, nonstatins, and fribrates. Some medications may be prescribed for other risk factors for heart disease like blood sugar and obesity such as empagliflozin, canagliflozin, metformin, liraglutide, orlistat, and semaglutide. Heart surgery may be needed to treat this condition. Some procedures include percutaneous coronary intervention (PCI), coronary artery bypass grafting (CABG), and transmyocardial laser revascularization (coronary endarterectomy). Preventative procedures like bariatric surgery can help lower coronary heart disease risk.
Believing that Gary, the Nosferatu chief, has stolen the sarcophagus, the fledgling is sent to Hollywood to find him; after locating a captured Nosferatu for Gary, he reveals that the Giovanni vampire clan stole the sarcophagus. The fledgling infiltrates the Giovanni mansion and finds the sarcophagus guarded by the Kuei-Jin, who claim their leader, Ming-Xiao, has allied with LaCroix. The locked sarcophagus is returned to LaCroix's tower, and Beckett, a vampire scholar, tells the fledgling that the only person who can open it has been abducted by Bach to lure LaCroix. The fledgling kills Bach and learns that the sarcophagus's key has been stolen. The fledgling returns to LaCroix, learning that the Sabbat tried to steal the sarcophagus to destroy it and prevent Gehenna, then kills the Sabbat leader to disperse his followers. The fledgling is met by Ming-Xiao, who offers an alliance. Ming-Xiao reveals that she has the key, and LaCroix killed Grout to prevent his powerful insight from unveiling LaCroix's plans; Ming-Xiao disguised herself as Nines at the mansion to frame him. Denying Ming-Xiao's claims, LaCroix rescinds the blood hunt on Nines and entrusts the fledgling with recruiting the anarchs to punish the Kuei-Jin for murdering Grout. The fledgling finds Nines hiding in Griffith Park, and they are then attacked by a werewolf, and Nines is badly injured. The fledgling escapes with Jack, who reveals that LaCroix has issued an execution order on the fledgling for framing Nines on Ming-Xiao's orders.
Pioglitazone, sold under the brand name Actos among others, is an anti-diabetic medication used to treat type 2 diabetes. It may be used with metformin, a sulfonylurea, or insulin. Use is recommended together with exercise and diet. It is not recommended in type 1 diabetes. It is taken by mouth. Common side effects include headaches, muscle pains, inflammation of the throat, and swelling. Serious side effects may include bladder cancer, low blood sugar, heart failure, and osteoporosis. Use is not recommended in pregnancy or breastfeeding. It is in the thiazolidinedione (TZD) class and works by improving sensitivity of tissues to insulin. Pioglitazone was patented in 1985, and came into medical use in 1999. It is available as a generic medication. In 2023, it was the 133rd most commonly prescribed medication in the United States, with more than 4 million prescriptions. It was withdrawn in France and Germany in 2011.
Sources: en.wikipedia.org
Narcotics in Bolivia, South America, is a subject that primarily involves the coca crop, used in the production of the drug, cocaine. Trafficking and corruption have been two of the most prominent negative side-effects of the illicit narcotics trade in Bolivia and the country's government has engaged in negotiations with the United States (US) as result of the industry's ramifications.
Superficial burns may be managed with little more than simple pain medication, while major burns may require prolonged treatment in specialized burn centers. Cooling with tap water may help pain and decrease damage; however, prolonged cooling may result in low body temperature. Partial-thickness burns may require cleaning with soap and water, followed by dressings. It is not clear how to manage blisters, but it is probably reasonable to leave them intact if small and drain them if large. Full-thickness burns usually require surgical treatments, such as skin grafting. Extensive burns often require large amounts of intravenous fluid, due to capillary fluid leakage and tissue swelling. The most common complications of burns involve infection. Tetanus toxoid should be given if not up to date. In 2015, fire and heat resulted in 67 million injuries. This resulted in about 2.9 million hospitalizations and 176,000 deaths. Among women in much of the world, burns are most commonly related to the use of open cooking fires or unsafe cook stoves. Among men, they are more likely a result of unsafe workplace conditions. Most deaths due to burns occur in the developing world, particularly in Southeast Asia. While large burns can be fatal, treatments developed since 1960 have improved outcomes, especially in children and young adults. In the United States, approximately 96% of those admitted to a burn center survive their injuries. The long-term outcome is related to the size of burn and the age of the person affected.
=== In French === Sylvie Aprile, La Deuxième République et le Second Empire, Pygmalion, 2000 Choisel, Francis, La Deuxième République et le Second Empire au jour le jour, chronologie érudite détaillée, Paris, CNRS Editions, 2015. Inès Murat, La Deuxième République, Paris: Fayard, 1987 Philippe Vigier, La Seconde République, (series Que sais-je?) Paris: Presses Universitaires de France, 1967
28 September The 15-year-old girl killed in Croydon, South London the previous day is named locally as Elianne Andam. Police are given an extra 24 hours to question the 17-year-old suspect. The landmark Sycamore Gap Tree, beside Hadrian's Wall in Northumberland, is illegally felled. A 16-year-old boy is subsequently arrested on suspicion of criminal damage. 29 September A school bus carrying 58 people overturns between junction 4 and 5 of the M53 motorway, killing a 15-year-old girl and the driver. A major incident is declared by North West Ambulance Service and Liverpool's Alder Hey Children's Hospital. Dozens of others are treated for injuries, and several are hospitalised. A 17-year-old boy appears in court charged with the murder of Elianne Andam, and is remanded in youth detention to appear before the Old Bailey on 3 October. A second person – a man in his 60s – is arrested in correction with the cutting-down of the world-famous Sycamore Gap Tree. The 16-year-old boy arrested over the incident the previous day is released on bail. In an interview with The Sun, Prime Minister Rishi Sunak reinforces his pro-motorist stance, saying he wants to stop "hare-brained" road calming and safety schemes – including 20 mph zones and low-traffic neighbourhoods – putting an end to what he refers to as a "war on motorists".
The society – which only admitted men at the time – initially mistook Benett for a man due to her reputation as a scientist and her unusual first name, addressing her diploma of admission to "Dominum" (Master) Benett. 1840: Scottish fossil collector and illustrator Lady Eliza Maria Gordon-Cumming invited geologists Louis Agassiz, William Buckland and Roderick Murchison to examine her collection of fish fossils. Agassiz confirmed several of Gordon-Cumming's discoveries as new species. 1843: During a nine-month period in 1842–43, English mathematician Ada Lovelace translated Luigi Menabrea's article on Charles Babbage's newest proposed machine, the Analytical Engine. With the article, she appended a set of notes. Her notes were labelled alphabetically from A to G. In note G, she describes an algorithm for the Analytical Engine to compute Bernoulli numbers. It is considered the first published algorithm ever specifically tailored for implementation on a computer, and Ada Lovelace has often been cited as the first computer programmer for this reason. The engine was never completed, so her program was never tested. 1843: British botanist and pioneering photographer Anna Atkins self-published her book Photographs of British Algae, illustrating the work with cyanotypes. Her book was the first book on any subject to be illustrated by photographs. 1846: British zoologist Anna Thynne built the first stable, self-sustaining marine aquarium.
Sources: en.wikipedia.org
Only a small number of early-stage human studies have been reported, and most were limited in size and duration. No large late-stage program has established a general efficacy or safety profile. The evidence base is therefore thin compared with approved medicines.
The peptide is listed as prohibited in competitive sport, so laboratories develop detection methods and monitor for its presence. Its appearance in enforcement reports reflects that classification rather than any approved athletic use. Analytical work in this area focuses on identifying the molecule and its breakdown products in biological samples.
Chromatographic separation combined with mass spectrometry identifies the peptide and estimates its amount in a sample. Testing can confirm whether the expected molecule is present and at what concentration. It cannot establish how a product was manufactured or whether it meets any purity standard.
It is a synthetic seven-amino-acid peptide modeled on alpha-melanocyte-stimulating hormone. It carries two non-natural substitutions and a cyclic bridge that increase its stability relative to the natural hormone. It circulates as a research chemical and is not an approved medicine.