LC-MS is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Last reviewed on 2026-08-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
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 of this peptide varies by country. It holds no marketing authorization as a medicine in the United States, the European Union, or most other jurisdictions. Some countries classify products containing it as prescription-only or unlicensed medicines, which restricts lawful supply. Authorities have issued public notices warning that unregulated products may contain undeclared or incorrect ingredients. The molecule also appears on prohibited lists for competitive sport. These measures address supply oversight rather than any approved therapeutic role.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic cyclic heptapeptide | Analogue of alpha-melanocyte-stimulating hormone |
| Common synonyms | MT-II; melanotan 2 | No internationally accepted non-proprietary name |
| Typical presentation | Lyophilised powder in a sealed vial | Often supplied alongside a separate diluent |
| Regulatory status | Unapproved therapeutic substance | Customs seizure reported in several jurisdictions |
| Reported route in use | Subcutaneous injection | Self-administered outside clinical settings |
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.
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.
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 peptide was developed during the 1980s by researchers investigating melanocortin signalling and skin pigmentation pathways. Early work focused on analogues of alpha-melanocyte-stimulating hormone that would resist enzymatic breakdown more effectively than the parent molecule. Melanotan-2 emerged from that programme as a shortened, cyclised variant. Reports describing its synthesis and receptor activity later appeared in the scientific literature. Commercial availability grew through unregulated channels rather than through pharmaceutical approval.
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.
Identity testing for a cyclic peptide of this size usually relies on reversed-phase high-performance liquid chromatography coupled to mass spectrometry. The mass spectrum confirms molecular weight, while the chromatographic trace indicates the proportion of related impurities. Tandem mass spectrometry can provide sequence-level information when fragmentation data are compared against a reference standard. Nuclear magnetic resonance is sometimes used to confirm the lactam bridge, although it requires more material and greater operator expertise than routine chromatographic methods.
== Co-Workers == Klaus Mosbach supervised more than sixty Ph.D.’s over the years. A number of highly recognized scientists emerged from this pool, including the following professors C. Borrebaeck (in part), B.Sellergren (who is now a professor in Germany). P. Brodelius, Leif Bulow, B. Danielsson, B. Hahn-Hägerdahl (in part), A.C. Koch. Schmidt, P.O. Larsson, C. F. Mandenius, B. Mattiasson, M.O. Månsson, I.A. Nicholls (starting as post doc), R. Ohlsson (in part), Lei Ye and S. Olsson working all in Sweden. To this a number of Professors working in other countries outside Sweden including, L.Fischer, K. Haupt, C.Lowe, H.Zhang, Deepak Chandrasekaran. Mosbach collaborated with numerous companies over the years, including Biogen and later Hybritech, Eli Lilly, Igen, Hofman la Roche and was involved in the formation of start-up companies by himself likewise former students of him have been successful in starting up companies like B.Ekberg, N.Siegbahn, Kurt Nilsson, Kjell Nilsson, Dariao Kriz.
Notch signaling is triggered via direct cell-to-cell contact, mediated by interactions between the Notch receptor protein in the signal receiving cell and a ligand in an adjacent signal transmitting cell. These type 1 single-pass transmembrane proteins fall into the Delta/Serrate/Lag-2 (DSL) family of proteins which is named after the three canonical Notch ligands. Delta and Serrate are found in Drosophila while Lag-2 is found in C. elegans. Humans contain 3 Delta homologs, Delta-like 1, 3, and 4, as well as two Serrate homologs, Jagged 1 and 2. Notch proteins consist of a relatively short intracellular domain and a large extracellular domain with one or more EGF motifs and a N-terminal DSL-binding motif. EGF repeats 11-12 on the Notch extracellular domain have been shown to be necessary and sufficient for trans signaling interactions between Notch and its ligands. Additionally, EGF repeats 24-29 have been implicated in inhibition of cis interactions between Notch and ligands co-expressed in the same cell.
Similarly, Sumo wrestlers are typically categorized by BMI as "severely obese" or "very severely obese", but one study of college-aged Sumo wrestlers found that 40% of them were no longer categorized as obese when body fat percentage (with a cutoff of <25%) was used instead of BMI; this was attributed to their very high lean body mass. The Edmonton Obesity Staging System (EOSS), developed in Canada, supplements BMI-based classification by incorporating medical, functional, and mental-health factors into a five-stage clinical framework.
Sources: en.wikipedia.org
The MECP2 locus is X-linked and the disease-causing alleles are dominant. Due to its prevalence in females, it has been linked to male lethality, or to a predominant transmission with the paternal X chromosome; nevertheless, in rare cases some males can also be affected by Rett syndrome. Males with gene duplications of MECP-2 at the Xq28 locus are also at risk for recurrent infections & meningitis in infancy. Mutations in the MECP2 gene have also been identified in people with several other disorders affecting the central nervous system. For example, MECP2 mutations are associated with some cases of moderate to severe X-linked intellectual disability. Mutations in the gene have also been found in males with severe brain dysfunction (neonatal encephalopathy) who live only into early childhood. In addition, several people with features of both Rett syndrome and Angelman syndrome (a condition characterized by intellectual disability, problems with movement, and inappropriate laughter and excitability) have mutations in the MECP2 gene. Lastly, MECP2 mutations or changes in the gene's activity have been reported in some cases of autism (a developmental disorder that affects communication and social interaction). More recent studies reported genetic polymorphisms in the MeCP2 gene in patients with systemic lupus erythematosus (SLE). SLE is a systemic autoimmune disease that can affect multiple organs. MeCP2 polymorphisms have been reported so far in European-derived and Asian lupus patients.
Half-Life: Escape from City 17 is a two-part Canadian short film written, developed, and filmed by the Purchase Brothers. The film is set in the Half-Life universe, during the events of Half-Life 2 and Half-Life 2: Episode One. Both films were critically acclaimed. Part One was released on February 13, 2009; and Part Two was released on August 24, 2011.
In industry, a similar reaction is carried out at high pressure and temperature in the presence of quaternary ammonium or phosphonium salts as a catalyst. Reaction of ethylene oxide with formaldehyde at 80–150 °C in the presence of a catalyst leads to the formation of 1,3-dioxolane:
Sources: en.wikipedia.org
The monoisotopic mass is the sum of the masses of the atoms in a molecule using the unbound, ground-state, rest mass of the principal (most abundant) isotope for each element. The monoisotopic mass of a molecule or ion is the exact mass obtained using the principal isotopes. Monoisotopic mass is typically expressed in daltons (Da). This is also known as the exact (a.k.a theoretical) mass. For typical organic compounds, where the monoisotopic mass is most commonly used, this also results in the lightest isotope being selected. For some heavier atoms such as iron and argon the principal isotope is not the lightest isotope. The mass spectrum peak corresponding to the monoisotopic mass is often not observed for large molecules, but can be determined from the isotopic distribution.
== History == EcPLA was first described in the scientific literature by a team that included Adam Halberstadt, Alexander Stratford, Jason Wallach, and David E. Nichols in 2019. It was developed by Lizard Labs. The drug was encountered online as a novel designer drug in around 2020 and became more widely available in early 2022.
=== Gastroenterology and cancer screening === A 2024 study published in The American Journal of Gastroenterology examined real-world adherence to repeat stool-based colorectal cancer screening among individuals at average risk, using fecal immunochemical tests (FIT) and multi-target stool DNA tests (mt-sDNA). The authors analyzed patterns of repeat testing and evaluated factors associated with adherence over time.
== Law and politics == Reports of Patent, Design and Trademark Cases, a case-law journal published by the Oxford University Press on behalf of the UK Intellectual Property Office Revolutionary Policy Committee, a faction within UK Independent Labour Party during the 1930s Reynolds Porter Chamberlain, a law firm based in London Revised Penal Code of the Philippines Rules of Professional Conduct, relating to U.S. lawyers' ethical rules, see American Bar Association Model Rules of Professional Conduct
Sources: en.wikipedia.org
No. No major regulatory agency has granted a marketing authorisation for melanotan II as a medicine. Products sold under this name are generally presented as laboratory reagents and are not subject to the batch-release testing applied to approved drugs.
It was developed in the 1980s by researchers investigating analogues of alpha-melanocyte-stimulating hormone for pigmentation and related endpoints. Early work included small human studies during the 1990s. Development did not progress to licensing, and the compound remained a research and grey-market item.
Peptides are prone to truncation, oxidation and aggregation during synthesis and handling. Without independent testing, a buyer cannot confirm the identity or the content of a vial. Analytical surveys of unapproved peptide products have repeatedly found discrepancies between label claims and measured composition.
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.