If you have been reading about regulatory status and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Updated 2025-07-14. Numbers and descriptions here follow the published literature rather than marketing material.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, which separates the target peptide from truncated or oxidised impurities. Mass spectrometry, most often coupled to liquid chromatography, confirms molecular mass and detects substitutions that chromatography alone may miss. Amino acid analysis and peptide mapping supply additional structural evidence, while nuclear magnetic resonance is reserved for full structural confirmation. Laboratories that examine samples sold online report wide variation in actual content, with some vials containing little or none of the labelled material.
Melanotan-2 appears on the World Anti-Doping Agency prohibited list within the peptide hormone class, and several national regulators treat it as an unapproved prescription substance. Some countries restrict importation or sale for personal use. Because the compound is widely traded as a research chemical, the practical legal picture differs between jurisdictions and shifts over time. Human safety data covering long periods are limited, and whether repeated pigmentation changes carry any lasting risk to melanocytes remains an open question.
Freeze-dried melanotan-2 is normally kept as a desiccated powder at minus twenty degrees Celsius or lower, shielded from light and moisture. Peptides of this size degrade through hydrolysis, oxidation and deamidation, and each pathway accelerates as temperature and water activity rise. Repeated freeze-thaw cycles promote aggregation and loss of material, so aliquoting a stock solution before freezing is standard laboratory practice. Once dissolved, the solution is markedly less stable than the powder. In laboratory work, solutions are generally refrigerated and used within days rather than kept for months.
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.
| Property | Value | Notes |
|---|---|---|
| Typical storage temperature | -20 °C or below | For the lyophilised powder, desiccated |
| Storage form | Sealed vial, protected from light | Amber glass or foil-wrapped containers |
| Reconstituted stability | Short, refrigerate | Degradation accelerates in solution |
| Typical analytical method | Reversed-phase HPLC with mass spectrometry | Purity assessment plus identity confirmation |
| Common synonyms | Melanotan II, MT-II | Also written melanotan-2 |
Routine characterisation relies on reversed-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres, using a C18 column and a water-acetonitrile gradient containing trifluoroacetic acid. Electrospray ionisation mass spectrometry confirms the expected molecular mass and can reveal truncated or oxidised by-products that co-elute poorly. Sequence and stereochemistry require additional work, such as peptide mapping or amino acid analysis, because a chromatographic purity figure alone does not distinguish a diastereomer from the target peptide. Independent testing of research-grade material frequently shows measured content below the stated label, so a certificate of analysis is best read together with the method that produced it.
Melanotan-2 is handled in the laboratory as a lyophilised powder that dissolves readily in water, dimethyl sulfoxide and dimethylformamide, with limited solubility in ethanol. Stock solutions prepared in an organic solvent often precipitate when diluted into aqueous buffer, so gradual dilution with mixing is standard practice. The peptide carries a tryptophan residue and a histidine residue, both sensitive to oxidation and to alkaline conditions. Working solutions are therefore kept near neutral to slightly acidic pH, protected from light, and consumed within the same working session whenever that is practical.
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.
Scientific discussion of Melanotan-2 spans pharmacology, dermatology, and public-health literature. Laboratory studies examine its receptor binding and cellular effects, while clinical reports describe outcomes observed after unregulated use. These two bodies of work differ in rigour and intent. Peer-reviewed trials of the compound as a medicine are limited, so much of the available information comes from case reports and surveillance data. Authors frequently note the gap between experimental findings and real-world use.
Reported observations after unregulated use include shifts in skin pigmentation and, in some accounts, unintended changes to moles and other lesions. Whether these outcomes are causally linked to the compound, and how often they occur, remain open questions because controlled data are scarce. The absence of standardised dosing and verified product purity complicates interpretation. Researchers have called for better surveillance and analytical characterisation of samples obtained outside regulated channels. Conclusions drawn from anecdotal evidence should be treated as provisional.
Melanotan-2 has not received marketing authorisation from major regulatory agencies for any therapeutic indication. Several jurisdictions classify it as a prescription-only medicine or a controlled substance when supplied for human use. Because approved products do not exist, material sold online usually sits outside pharmaceutical supply chains and formal quality oversight. Regulators have issued public notices describing the compound as unapproved. Enforcement varies, and the legal position differs between countries, which complicates any single general statement about its status.
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.
Agilent ChemStation is a software package to control Agilent liquid chromatography, gas chromatography, and ultraviolet-visible spectroscopy systems such as the 1050, 1100 and 1200 Series HPLC system and the 8453 and 8454 single-beam diode array detector spectrophotometers. It is an evolution of the Hewlett-Packard ChemStation System. Two versions are available: one ("online") in connection with the modules of the HPLC chain is designed to control instruments and run experiments, and the other ("offline"), without a connection with the HPLC chain, is designed to analyze data. ChemStation is structured around a number of registers. Two of the more important registers are CHROMREG and CHROMRES, the chromatographic data registers. Other special registers exist for the UV-vis implementation of the software. ChemStation has a command line interpreter and can run macros. Those macros are files grouping a set of commands. These files possess a .mac extension. ChemStation can import analysis lists and export result files in XML by adding new lines to the ChemStation.ini configuration file. This is a feature to implement the connection with a Laboratory information management system (LIMS).
At the conclusion of the 2019 AFL season, Ryder requested a trade to St Kilda. The trade was finalised on 15 October and Ryder was traded to St Kilda along with Port Adelaide teammate Dougal Howard and pick 10 and a 2020 fourth-round selection, in return for the Saints' picks 12 and 18 and a 2020 third-round selection. Ryder nominated to join St Kilda ahead of his former club Essendon. He chose to leave Port Adelaide due to a perceived lack of opportunity in the ruck division at the Power. Of the move, Ryder stated that "I guess the way things have panned out at Port Adelaide over the past couple of years is Port Adelaide’s brought in Scotty Lycett, who's a terrific ruckman, and they've got a couple of young blokes on the list that probably need a bit more time to develop. And I guess being my age and stuff I’m taking away that opportunity for them, so I'm very understanding of the football club and respect their decision. But I feel like I've still got a lot more to give, so I'll be going down to Moorabbin." On choosing to join the Saints ahead of his former team, Ryder admitted that he was leaning towards rejoining the Bombers until he toured their facilities; "I just didn't get like a really, really good feeling from going back there", said Ryder in October 2019. "But then I went down to Moorabbin and it was a sense of like excitement and in the end thats what I ended up basing my decision on." Ryder played 14 of a possible 19 games for the Saints in the 2020 season.
In particular, decreased access to public health services such as syringe exchange programs and confiscation of syringes can precipitate a cascade of health harms. Geographic diffusion of epidemics from the northern border states elsewhere is also possible with the rotation of police and military personnel stationed in drug conflict areas with high infection prevalence. With increased drug use, there has been a parallel rise in demand for drug user treatment in Mexico.
Using this technique the resolution of deuterium exchange is determined by the size of the peptides produced during digestion. Pepsin, an acid protease, is commonly used for proteolysis, as the quench pH must be maintained during the proteolytic reaction. To minimize the back-exchange, proteolysis and subsequent mass spectrometry analysis must be done as quickly as possible. HPLC separation of the peptic digest is often carried out at low temperature just prior to electrospray mass spectrometry to minimize back-exchange. More recently, UPLC has been used due to its superior separation capabilities. It was proposed in 1999 that it might be possible to achieve single-residue resolution by using collision-induced dissociation (CID) fragmentation of deuterated peptides in conjunction with tandem mass spectrometry. It was soon discovered that CID causes "scrambling" of the deuterium position within the peptides. However, fragmentation produced by MALDI in-source decay (ISD), electron capture dissociation (ECD), and electron transfer dissociation (ETD) proceed with little or no scrambling under the correct experimental conditions. Scrambling of the isotopic labeling is caused by collisional heating prior to dissociation of the ion and while CID do cause scrambling, collisional heating can also occur during ionization and ion transport.
=== Endocannabinoid concentration === It is established that AM404 increases concentrations of the endogenous cannabinoid anandamide within the synaptic cleft, contributing to its analgesic activity. This has been well characterised as involving endocannabinoid transporter inhibition, but the precise transporter responsible is yet to be determined. AM404 was originally reported to be an endogenous cannabinoid reuptake inhibitor, preventing the transport of anandamide and other related compounds back from the synaptic cleft, much in the same way that common selective serotonin reuptake inhibitor (SSRI) antidepressants prevent the reuptake of serotonin. Earlier work on the mechanism of AM404 suggested that the inhibition of fatty acid amide hydrolase (FAAH) by AM404 was responsible for all of its attributed reuptake properties, since intracellular FAAH hydrolysis of anandamide changes the intra/extracellular anandamide equilibrium. However, this is not the case, as newer research on FAAH knockout mice has found that brain cells internalize anandamide through a selective transport mechanism which is independent of FAAH activity. It is this mechanism which is inhibited by AM404.
Sources: en.wikipedia.org
=== Age of onset === Feline hypersomatotropism is usually diagnosed in elderly cats. The average age of diagnosis is between 10 and 11 years with a range of 4–17 years. The age range of dogs reported with growth hormone secreting tumours is between 7 and 10 years. The age range of bitches with progestone induced hypersomatotropism is 4–11 years, for bitches with hypersomatotropism resulting from the estrous cycle the age range is between 6 and 13 years.
The submucosa (tela submucosa), or submucosal layer, is a thin layer of tissue in various organs of the gastrointestinal, respiratory, and genitourinary tracts. It is the layer of dense irregular connective tissue that supports the mucosa (mucous membrane) and joins it to the muscular layer, the bulk of overlying smooth muscle (fibers running circularly within layer of longitudinal muscle). The submucosa (sub- + mucosa) is to a mucous membrane what the subserosa (sub- + serosa) is to a serous membrane.
As a modified atmosphere, pure or mixed with carbon dioxide, to nitrogenate and preserve the freshness of packaged or bulk foods (by delaying rancidity and other forms of oxidative damage). Pure nitrogen as food additive is labelled in the European Union with the E number E941. In incandescent light bulbs as an inexpensive alternative to argon. In fire suppression systems for Information technology (IT) equipment. In the manufacture of stainless steel. In the case-hardening of steel by nitriding. In some aircraft fuel systems to reduce fire hazard (see inerting system). To inflate race car and aircraft tires, reducing the problems of inconsistent expansion and contraction caused by moisture and oxygen in natural air. Nitrogen is commonly used during sample preparation in chemical analysis. It is used to concentrate and reduce the volume of liquid samples. Directing a pressurised stream of nitrogen gas perpendicular to the surface of the liquid causes the solvent to evaporate while leaving the solute(s) and un-evaporated solvent behind. Nitrogen can be used as a replacement, or in combination with, carbon dioxide to pressurise kegs of some beers, particularly stouts and British ales, due to the smaller bubbles it produces, which makes the dispensed beer smoother and headier. A pressure-sensitive nitrogen capsule known commonly as a "widget" allows nitrogen-charged beers to be packaged in cans and bottles. Nitrogen tanks are also replacing carbon dioxide as the main power source for paintball guns.
=== Resignation and asylum of Grand Master Alfonso Vidal === On December 15, Alfonso Vidal signed a copy of Masonic Decree 634 and handed over temporary administration of the Grand Lodge to Acting Grand Master to Armando Guerra Lozano, the Grand Master of Ceremonies, and travelled to Mexico with his wife. Alfonso Vidal did participate in the ceremony, but afterwards, the Grand Lodge of Cuba lost communication with him. He was scheduled to return to Havana on December 21, but when he did not return, the Grand Lodge declared that this indicated a "tacit resignation of his duties." They iterated that they had no knowledge of his whereabouts, and were concerned what fate might have befallen him in Mexico. In late December 2022 or early January 2023, Alfonso Vidal and his wife crossed the Mexico–United States border into Texas, where they officially requested Asylum in the United States. The Grand Lodge of Florida provided them financial assistance, and a Masonic Lodge in Brownsville, Texas helped them find temporary lodgings. On January 3, 2023, Alfonso Vidal revealed that he was still alive and publicly tendered his resignation from the office.
Themed core specialties (A&E, Intensive Therapy Unit [ITU] and anaesthetics) Surgical specialties Medical specialties Psychiatry Run-through specialties (e.g., general practice, clinical radiology, pathology, paediatrics) The first four categories all run on a similar structure: the Trainee first completes a two-year structured and broad-based core training programme in that field (e.g., core medical training), which makes them eligible for competitive entry into an associated specialty training scheme (e.g., gastroenterology if core medical training has been completed). The Core training years are referred to as CT1 and CT2, and the specialist years are ST3 onwards until completing training. Core training and the first year or two of speciality training are equivalent to the old Senior House Officer jobs. It is customary for trainees in these areas to sit their Membership examinations (e.g., Royal College of Physicians (MRCP), Royal College of Surgeons (MRCS)) in order to progress and compete for designated sub-specialty training programmes that attract a national training number as specialty training year 3 (ST3) and beyond – up to ST9 depending on the particular training specialty. In the fifth category, the trainee immediately starts specialty training (ST1 instead of CT1) progressing up to Consultant level without break or further competitive application process (run-through training).
Sources: en.wikipedia.org
In 2016, the World Health Organization estimated that 34 million people used opioids and 19 million used opiates. Of these, about 27 million people had opioid dependence, with the majority—but a decreasing number—using illicit heroin. In 2015, 118,000 people died from opioid use disorders, causing almost one-third of all drug-related deaths.
Absorption is the journey of a drug travelling from the site of administration to the site of action. The drug travels by some route of administration (oral, topical-dermal, etc.) in a chosen dosage form (e.g., tablets, capsules, or in solution). Absorption by some other routes, such as intravenous therapy, intramuscular injection, enteral nutrition, is even more straightforward and there is less variability in absorption and bioavailability is often near 100%. Intravascular administration does not involve absorption, and there is no loss of drug. The fastest route of absorption is inhalation. Absorption is a primary focus in drug development and medicinal chemistry, since a drug must be absorbed before any medicinal effects can occur. Moreover, the drug's pharmacokinetic profile can be easily and significantly changed by adjusting factors that affect absorption.
Eric M. Verdin is a Belgian geroscientist, researcher, and professor who has served as president and chief executive officer of the Buck Institute for Research on Aging since 2016. Verdin’s research focuses on metabolism, diet, and the different proteins and molecules that affect the aging process and its associated diseases. He has published more than 210 papers and has more than 15 patents.
== History of study == In 1557, the position-movement sensation was described by Julius Caesar Scaliger as a "sense of locomotion". In 1826, Charles Bell expounded the idea of a "muscle sense", which is credited as one of the first descriptions of physiologic feedback mechanisms. Bell's idea was that commands are carried from the brain to the muscles, and that reports on the muscle's condition would be sent in the reverse direction. In 1847, the London neurologist Robert Todd highlighted important differences in the anterolateral and posterior columns of the spinal cord, and suggested that the latter were involved in the coordination of movement and balance. At around the same time, Moritz Heinrich Romberg, a Berlin neurologist, was describing unsteadiness made worse by eye closure or darkness, now known as the eponymous Romberg's sign, once synonymous with tabes dorsalis, that became recognised as common to all proprioceptive disorders of the legs. In 1880, Henry Charlton Bastian suggested "kinaesthesia" instead of "muscle sense" on the basis that some of the afferent information (back to the brain) comes from other structures, including tendons, joints, and skin. In 1889, Alfred Goldscheider suggested a classification of kinaesthesia into three types: muscle, tendon, and articular sensitivity. In 1906, the term proprio-ception (and also intero-ception and extero-ception) is attested in a publication by Charles Scott Sherrington involving receptors. He explains the terminology as follows:
It was first synthesised in 1811 by Pierre Louis Dulong, who lost three fingers and an eye to its explosive tendencies. As a dilute gas it is less dangerous and is thus used industrially to bleach and sterilise flour. Nitrogen tribromide (NBr3), first prepared in 1975, is a deep red, temperature-sensitive, volatile solid that is explosive even at −100 °C. Nitrogen triiodide (NI3) is still more unstable and was only prepared in 1990. Its adduct with ammonia, which was known earlier, is very shock-sensitive: it can be set off by the touch of a feather, shifting air currents, or even alpha particles. For this reason, small amounts of nitrogen triiodide are sometimes synthesised as a demonstration to high school chemistry students or as an act of "chemical magic". Chlorine azide (ClN3) and bromine azide (BrN3) are extremely sensitive and explosive. Two series of nitrogen oxohalides are known: the nitrosyl halides (XNO) and the nitryl halides (XNO2). The first is very reactive gases that can be made by directly halogenating nitrous oxide. Nitrosyl fluoride (NOF) is colourless and a vigorous fluorinating agent. Nitrosyl chloride (NOCl) behaves in much the same way and has often been used as an ionising solvent. Nitrosyl bromide (NOBr) is red. The reactions of the nitryl halides are mostly similar: nitryl fluoride (FNO2) and nitryl chloride (ClNO2) are likewise reactive gases and vigorous halogenating agents.
Sources: en.wikipedia.org
The lyophilised solid is best kept cold, dry and dark, typically at minus twenty degrees Celsius. Moisture and repeated warming cycles are the main causes of degradation. Solutions prepared from the powder are less stable and are normally used quickly.
Reversed-phase liquid chromatography assesses purity, while mass spectrometry confirms molecular mass and detects sequence errors. Amino acid analysis and peptide mapping add structural detail. These techniques are complementary rather than interchangeable.
It is listed as a prohibited peptide hormone by the World Anti-Doping Agency. No medicines regulator has approved it for human use. Import and sale rules vary by country.
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.