The short version of mass spectrometry fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2025-09-05 and is reviewed periodically as new material appears.
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.
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.
| 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 |
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.
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.
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.
By 2014, around 20 companies, particularly from emerging markets, were developing biosimilar versions of trastuzumab after Roche/Genentech's patents expired in 2014 in Europe, and in 2019 in the United States. In January 2015, BIOCAD announced the first trastuzumab biosimilar approved by the Ministry of Health of the Russian Federation. Iran also approved its own version of the monoclonal antibody in January 2016, as AryoTrust, and announced its readiness to export the drug to other countries in the Middle-East and Central Asia when trade sanctions were lifted. In 2016, the investigational biosimilar MYL-1401O showed comparable efficacy and safety to the Herceptin branded trastuzumab. Trastuzumab-dkst (Ogivri, Mylan GmbH) was approved in the United States in December 2017, to "treat people with breast cancer or gastric or gastroesophageal junction adenocarcinoma whose tumors overexpress the HER-2 gene." Ogivri was authorized for medical use in the European Union in December 2018. In November 2017, the European Commission authorized Ontruzant, a biosimilar from Samsung Bioepis Co., Ltd, for the treatment of early breast cancer, metastatic breast cancer and metastatic gastric cancer. Ontruzant is the first trastuzumab biosimilar to receive regulatory approval in the European Union. Herzuma was authorized for medical use in the European Union in February 2018. Herzuma, a trastuzumab biosimilar, was approved in the United States in December 2018.
Denbu (田麩), a food made by boiling powdered dried bonito flakes in sake and soy sauce, appears in an ancient 17th-century document called "Kokin Ryouri-shu" ("Collection of Ancient and Modern Cookbooks"). Tsukudani (佃煮), which appears in the 19th century colloquial dictionary "Risogonshuran" (俚言集覧) compiled by Ota Zensai (太田全斎), is made by boiling down small fish, shellfish, seaweed, and other ingredients in soy sauce to a rich flavor. The use of tsukudani is similar to furikake, but it is not usually called furikake in Japan today. The modern furikake was invented by several companies between the 1900s and 1920s for the purpose of tasty nourishment. Regarding modern furikake, the Japan Furikake Association recognized Futaba's "Gohan no Tomo" as the original in 1994, but revoked this recognition in 2022 and is conducting a reexamination. The association's conclusion has not been reached as of 2023. One account of the origin of furikake is that it was developed during the Taishō period (1912–1926) by a pharmacist in Kumamoto prefecture named Suekichi Yoshimaru (吉丸末吉). To address calcium deficiency in the Japanese population, Yoshimaru developed a mixture of ground fish bones with roast sesame seeds, poppy seeds, and seaweed that was made into a powder. This product, which he called Gohan no Tomo (ご飯の友, 'A Friend for Rice'), is generally considered the precursor to contemporary furikake. A food company in Kumamoto later acquired the product and was able to sell it commercially.
=== Other === Other physical integration methods (spray or spin coating, blending, and vacuum filtration) have been developed for paper electronics, but have yet to be implemented in paper-based microfluidic devices.
where ρ is the density, p is the pressure, ν is the kinematic viscosity, u is the flow velocity, and g is the body acceleration field. The above equation can be non-dimensionalized through selection of appropriate scales as follows:
High amounts of vapor particle deposition are believed to enter into the lungs with each puff because the particle size in e-cigarette vapors is within the respiratory range. After a puff, the inhaled vapor changes in the size distributions of particles in the lungs. This results in smaller exhaled particles. E-cigarette vapor is made up of fine and ultrafine particles of particulate matter. Vaping generates particulate matter 2.5 μm or less in diameter (PM2.5), but at notably less concentrations compared to cigarette smoke. Particle concentrations from vaping ranged from 6.6 to 85.0 μg/m3. Particle-size distributions of particulate matter from vaping differ across studies. The longer the puff duration the greater the amount of particles produced. The greater the amount of nicotine in the e-liquid the greater the amount of particles produced. Flavoring does not influence the particle emissions. The various kinds of devices such as cig-a-likes, medium-sized vaporizers, tanks, or mods may function at different voltages and temperatures. Thus, the particle size of the e-cigarette vapor can vary, due to the device used. Comparable to cigarette smoke, the particle size distribution mode of e-cigarette vapor ranged from 120 to 165 nm, with some vaping devices producing more particles than cigarette smoke.
Sources: en.wikipedia.org
Somatotrophs, which secrete growth hormone (a peptide hormone) Lactotrophs, which secrete prolactin (a peptide hormone) When using standard staining techniques, they cannot be distinguished from each other (though they can be distinguished from basophils and chromophobes), and are therefore identified simply as "acidophils".
Hand in hand, the zaibatsu and government led Japan through the process of industrialization, borrowing technology and economic policy from the West. Japan gradually took control of much of Asia's market for manufactured goods, beginning with textiles. The economic structure became very mercantilistic, importing raw materials and exporting finished products—a reflection of Japan's relative poverty in raw materials.
Three major genes are involved in determination of Drosophila sex. These are sex-lethal, sisterless, and deadpan. Deadpan is an autosomal gene which inhibits sex-lethal, while sisterless is carried on the X chromosome and inhibits the action of deadpan. An AAX cell has twice as much deadpan as sisterless, so sex-lethal will be inhibited, creating a male. However, an AAXX cell will produce enough sisterless to inhibit the action of deadpan, allowing the sex-lethal gene to be transcribed to create a female. Later, control by deadpan and sisterless disappears and what becomes important is the form of the sex-lethal gene. A secondary promoter causes transcription in both males and females. Analysis of the cDNA has shown that different forms are expressed in males and females. Sex-lethal has been shown to affect the splicing of its own mRNA. In males, the third exon is included which encodes a stop codon, causing a truncated form to be produced. In the female version, the presence of sex-lethal causes this exon to be missed out; the other seven amino acids are produced as a full peptide chain, again giving a difference between males and females. Presence or absence of functional sex-lethal proteins now go on to affect the transcription of another protein known as doublesex. In the absence of sex-lethal, doublesex will have the fourth exon removed and be translated up to and including exon 6 (DSX-M[ale]), while in its presence the fourth exon which encodes a stop codon will produce a truncated version of the protein (DSX-F[emale]).
=== TruD === TruD is able to modify a variety of RNA, and it is unclear how these different RNA substrates are recognized. PUS 7 modifies U2 snRNA at the position 35 and this modification will increase when the cells are in heat shock. Another modification is cytoplasmic tRNA in position 13, and position 35 in pre-tRNATyr. PUS 7 modifies almost specificity does not depend on the type of RNA as mRNA show pseudouridylated by PUS 7. Recognize this the sequence of the RNA, UGUAR with the second U being the nucleotide that will be modified. The pseudouridylation of mRNA by PUS 7 increases during heat shock, because the protein moves from the nucleus to the cytoplasm. The modification is thought to increase the stability of mRNA during heat shock before the RNA goes to the nucleus or mitochondria, but more studies are needed.
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.
The dry powder is more stable during transport and storage than a solution. It also allows a known amount of material to be reconstituted at a chosen concentration.