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 2025-11-05 and is reviewed periodically as new material appears.
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.
Quality assessment of research-grade peptide rests mainly on reversed-phase high-performance liquid chromatography for purity and on mass spectrometry for identity confirmation. A single main peak above a stated threshold, commonly ninety-eight percent by peak area, is the usual release criterion applied by suppliers. Independent analyses commissioned by laboratories and consumer organisations have repeatedly reported discrepancies between label claims and measured content, including truncated sequences, residual trifluoroacetate, and lower-than-declared peptide mass. Those findings do not establish that every supplier is unreliable, but they indicate that purity figures printed on a vial are claims requiring verification rather than settled facts.
Regulatory treatment varies by jurisdiction and has changed over time. In several countries the peptide is handled as an unapproved prescription medicine, and import or sale for human use is restricted, while elsewhere it falls under poisons or controlled-substance schedules. Enforcement activity against online vendors has been reported in Australia, New Zealand, the United Kingdom and the United States. Scholarly writing discusses melanotan-2 chiefly as an experimental tool and as a case study in unregulated peptide supply, and its precise legal position in any given country should be checked against current national schedules.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic cyclic heptapeptide | Analog of alpha-MSH with an internal lactam bridge |
| Molecular weight | Approximately 1024 daltons | Free base value; salt forms differ |
| Appearance | White to off-white powder | Usually supplied as a lyophilized solid |
| Solubility | Freely soluble in water | Poorly soluble in nonpolar solvents |
| Typical storage | −20 °C, dry, protected from light | Repeated freeze-thaw cycles degrade peptides |
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.
Regulatory status varies by jurisdiction, and the substance is frequently described as unapproved for therapeutic use. Some authorities classify it alongside prescription-only medicines or controlled categories, while others address it through general consumer protection rules. Analytical surveys have reported mismatches between label claims and measured content in products sold online, although the scope of such testing is limited. Whether these discrepancies are widespread remains an open question. Discussion in the literature therefore tends to combine chemistry, supply-chain observation and policy analysis.
The material is commonly handled as a lyophilized powder in sealed vials. The solid dissolves readily in water and in polar organic solvents, producing a clear solution after reconstitution. Light, heat and repeated freeze-thaw cycles are the concerns most often raised in handling guidance, because peptide bonds and the constrained ring can degrade. Working solutions are generally prepared fresh, and material left in solution is treated as less stable than the dry form. These properties shape how laboratories store and aliquot reference material.
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.
Activity is attributed to agonism at melanocortin receptors, particularly MC1R and MC4R. Activation of MC1R on melanocytes increases melanin synthesis, which underlies the reported tanning effect. MC4R engagement in the central nervous system is linked to appetite suppression and to effects on sexual arousal reported in early clinical studies. Those studies were small and were not designed to establish efficacy or long-term safety. Receptor selectivity among the melanocortin subtypes is not absolute, which complicates attribution of any effect to a single pathway.
Regulatory treatment varies by country. In the United States the peptide is not approved as a medicine, and products offered for human use may be treated as unapproved new drugs; some states also restrict sale. Australia, the United Kingdom, and European Union member states apply comparable restrictions to unapproved peptide products. Border agencies have seized shipments labelled as research chemicals. Classification may change over time, and the legal position for personal importation is not clearly settled in most published guidance.
Lyophilised melanotan-2 is supplied as a solid, which is more stable than a solution. The material is hygroscopic, so weighing is done quickly, in low humidity, with the container kept sealed. Reconstitution usually uses water for injection or bacteriostatic water, added down the wall of the vial to limit foaming. A reconstituted solution is held at 2 to 8 °C and kept away from light. Repeated freezing and thawing of the same vial is avoided because ice crystal formation and concentration effects degrade the peptide.
Reversed-phase high-performance liquid chromatography is the routine method for purity assessment. Peptides absorb near 214 nm because of the peptide bond, and a gradient of acetonitrile in water separates the intact peptide from deletion sequences, oxidised products, and earlier-eluting fragments at neutral pH. Electrospray ionisation mass spectrometry provides an orthogonal check: the measured mass must agree with the theoretical value. Amino acid analysis and peptide mapping confirm structure but are used less often. Reference standards remain scarce because the peptide is not described in any pharmacopoeia.
== External links == Bak Sangmee, From Strange Bitter Concoction to Romantic Necessity: The Social History of Coffee Drinking in South Korea. (Korea Journal Vol.45. No.2 Summer, 2005 pp. 37~59) Korea Coffee Market, Terarosa Coffee, Yunson, Lee Korea's coffee culture, korea.net Episode #33: The History of Coffee in Korea, KBS World The History of Coffee in Korea, Daniel Gray Korean Coffee Culture 101 – History & Timeline Archived 2016-12-06 at the Wayback Machine Café Culture in Seoul, Korea JungHee Jang, Korean Café Culture: What Korean Cafés Mean to Koreans Cultural Meaning and Power of Starbucks in South Korea
Glucose (glycemic) and insulin scores were determined by feeding 1000 kilojoules (239 kilocalories) of the food to the participants and recording the area under the glucose/insulin curve for 120 minutes then dividing by the area under the glucose/insulin curve for white bread. The result being that all scores are relative to white bread. The satiety value was determined by comparing how satiated participants felt within two hours after being fed a fixed number of calories (240 kilocalories) of a particular food while blindfolded (to ensure food appearance was not a factor), then dividing that number by how satiated the participants felt after eating white bread. White bread serves as the baseline of 100. In other words, foods scoring higher than 100 are more satisfying than white bread and those under 100 are less satisfying. The satiety value was negatively correlated to the amount eaten by participants at a subsequent buffet. ± indicate uncertainty in the data. For example 60 ± 12 means that there's a 95% chance the score is between 60-12 (48) and 60+12 (72), 60 being the highest probability assuming a bell curve. In practice, this means that if two foods have large uncertainty and have values close together then it is difficult to distinguish which score is higher.
A Dyson tree is a hypothetical genetically engineered plant (perhaps resembling a tree) capable of growing inside a comet, suggested by the physicist Freeman Dyson. Plants may be able to produce a breathable atmosphere within the hollow spaces of the comet (or maybe even within the plants themselves), utilising solar energy for photosynthesis and cometary materials for nutrients, thus providing self-sustaining habitats for humanity in the outer solar system analogous to a greenhouse in space, a shell grown by a mollusc or the actions of thermogenic plants, such as the skunk cabbage or the voodoo lily. A Dyson tree might consist of a few main trunk structures growing out from a comet nucleus, branching into limbs and foliage that intertwine, forming a spherical structure possibly dozens of kilometers across.
The first In-N-Outs had a common design, placing the kitchen "stand" between two lanes of cars. The "front" lane is nearest the street and the "back" lane away from the street. This location design is known as a double drive-thru. A metal awning provides shade for several tables for customers desiring to park and eat, but there is no indoor dining. A walk-up window faces the parking area. These restaurants store food and supplies in a separate building, and it is not uncommon for a driver to be asked to wait a moment while employees carry supplies to the kitchen across the rear lane. This design is a popular image on In-N-Out ads and artwork, which often shows classic cars such as 1965 Mustangs and 1968 Firebirds visiting the original restaurants. The original Covina restaurant, located on Arrow Highway west of Grand Avenue, was forced to close in the early 1990s due to re-engineering and development of the area. A modern design, drive-up/dining room restaurant was built a few hundred feet away. The replacement building was considerably larger, occupying nearly half the area of the original building's lot. Newer In-N-Out restaurants are based on standardized templates or blueprints, which are selected based on available space and expected traffic levels. While the external appearance of its buildings may vary to meet local zoning and architectural requirements, the interior floor plan and decor in most recently constructed In-N-Out restaurants are identical.
Sources: en.wikipedia.org
flask A vessel or container, most commonly a type of glassware, widely used in laboratories for a variety of purposes, such as preparing, holding, containing, collecting, and volumetrically measuring chemicals, samples, or solutions, or as a chamber in which a chemical reaction occurs. Flasks come in a number of shapes and sizes but are typically characterized by a relatively wide lower body which tapers into one or more narrower tubular sections with an opening at the top.
In China the adulteration and contamination of food and feed ingredients with inexpensive melamine and other compounds, such as cyanuric acid, ammeline and ammelide, is a common practice. These adulterants can be used to inflate the apparent protein content of products, so that inexpensive ingredients can pass for more expensive, concentrated proteins. Melamine by itself has not been thought to be toxic to animals or humans except possibly in very high concentrations, but the combination of melamine and cyanuric acid has been implicated in kidney failure. Reports that cyanuric acid may be an independently and potentially widely used adulterant in China have heightened concerns for animal and human health. Chinese protein export contamination was first identified after the recall of brands of cat and dog food in the 2007 pet food recalls. The recalls in North America, Europe and South Africa came in response to reports of kidney failure in pets. Chinese companies sold products claimed to be wheat gluten, rice protein or corn gluten, but which proved to be wheat flour adulterated with melamine, cyanuric acid, and other contaminants. The Chinese government was slow to respond, denying vegetable protein was exported from China and refusing to allow foreign food safety investigators to enter China. Ultimately, the Chinese government acknowledged that contamination had occurred and arrested the managers of two protein manufacturers identified and took other measures to improve food safety and product quality.
In April 2013, VESA published an article stating that the DisplayPort cable certification did not have distinct tiers for HBR and HBR2 bandwidth, and that any certified standard DisplayPort cable—including those certified under DisplayPort 1.1—would be able to handle the 21.6 Gbit/s bandwidth of HBR2 that was introduced with the DisplayPort 1.2 standard. The DisplayPort 1.2 standard defines only a single specification for High Bit Rate cable assemblies, which is used for both HBR and HBR2 speeds, although the DP cable certification process is governed by the DisplayPort PHY Compliance Test Standard (CTS) and not the DisplayPort standard itself. The DP8K certification was announced by VESA in January 2018, and certifies cables for proper operation at HBR3 speeds (8.1 Gbit/s per lane, 32.4 Gbit/s total). In June 2019, with the release of version 2.0 of the DisplayPort Standard, VESA announced that the DP8K certification was also sufficient for the new UHBR10 transmission mode. No new certifications were announced for the UHBR13.5 and UHBR20 modes. VESA is encouraging displays to use tethered cables for these speeds, rather than releasing standalone cables onto the market. It should also be noted that the use of Display Stream Compression (DSC), introduced in DisplayPort 1.4, greatly reduces the bandwidth requirements for the cable. Formats which would normally be beyond the limits of DisplayPort 1.4, such as 4K (3840 × 2160) at 144 Hz 8 bpc RGB/Y′CBCR 4:4:4 (31.4 Gbit/s data rate when uncompressed), can only be implemented by using DSC.
=== Next generation PEGylation === Chilkoti's research group has developed next-generation polyethylene glycol (PEG)-like conjugates that overcome the immunogenicity issues associated with traditional PEGylation. PEGylation—the attachment of polyethylene glycol (PEG) to biologics—is commonly used to increase their half-life or reduce their immunogenicity, but PEG has itself proven to be antigenic and can elicit a serious anaphylactic response. To overcome these limitations, he designed a new PEG-like stealth hyperbranched polymer that breaks up the long antigenic ethylene glycol sequence in PEG and presents them as much shorter side-chains along a polymer backbone. Peptides and proteins conjugated to this next-generation PEG-like polymer show even longer circulation than PEG conjugates, do not bind to pre-existing anti-PEG antibodies that most people have developed, and do not generate an immune response to this new polymer. He has demonstrated the utility of this technology with a peptide drug for type 2 diabetes, an enzyme drug used to treat gout and an aptamer drug.
== Non-insulin dependent (type 2) diabetes mellitus == The current releases of the downloadable AIDA software, and AIDA on-line, do not incorporate functions to model endogenous insulin secretion — which takes place in people with non-insulin dependent diabetes mellitus type 2, and healthy subjects without diabetes. Nevertheless, a wide number of people with insulin-treated type 2 diabetes mellitus have reported finding the AIDA diabetes simulator of use for learning about balancing insulin and diet in diabetes. This is because many of the principles of insulin dosage adjustment are remarkably similar in both type 1 and type 2 diabetes mellitus, and even without an endogenous insulin secretion model function, AIDA still can offer realistic simulations (from an educational perspective) for people with non-insulin dependent (type 2) diabetes mellitus. The AIDA developers have published a research paper in 2011 which includes reference to the incorporation of a dedicated function for pancreatic insulin secretion — to be added to a future release of the simulator.
Sources: en.wikipedia.org
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.
Melanotan-1, also called afamelanotide, is a shorter linear analog with a different amino acid sequence and no lactam ring. It has been evaluated in formal clinical programs, while melanotan-2 has not. The two are distinct molecules and are not interchangeable.
No. Bremelanotide is a related but distinct cyclic peptide that reached approved status for one specific clinical indication. Melanotan-2 is a separate molecule with its own sequence and properties. Shared ancestry in the melanocortin family does not make them the same substance.
Solutions are best kept cold, protected from light, and buffered to a pH that limits hydrolysis. Dividing a stock into single-use aliquots avoids repeated freeze-thaw cycles, which measurably reduce the intact parent peak over time.