If you have been reading about melanocortin receptor 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.
Last reviewed on 2026-01-10. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Regulatory status | Unapproved for therapeutic use | No marketing authorisation from major agencies |
| Legal classification | Varies by jurisdiction | Prescription-only or controlled in several countries |
| Common synonyms | Melanotan II; MT-II | Also referenced by catalogue codes |
| Typical analytical method | Reverse-phase HPLC | Often paired with mass spectrometry |
| Primary literature focus | Receptor pharmacology | Pigmentation and melanocortin signalling |
Solid peptide kept dry at minus twenty degrees Celsius, shielded from light and moisture, is generally considered stable for extended periods. Solutions are divided into single-use aliquots and held at minus twenty or minus eighty degrees Celsius, because repeated freeze-thaw cycles promote aggregation and loss of material to container surfaces. Hydrolysis of the backbone and oxidation of tryptophan are the principal degradation routes in aqueous solution, and both accelerate at ambient temperature. Hygroscopic uptake after a vial is opened can also shift the actual mass weighed, which affects any concentration calculated from it.
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 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.
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.
=== Radiology === Chest X-rays are useful in the follow-up routine of IPF patients. Plain chest X-rays are unfortunately not diagnostic but may reveal decreased lung volumes, typically with prominent reticular interstitial markings near the lung bases.
Burgers are produced in a made-to-order format, with Smashburger's smashing technique achieved by placing the meatball on a griddle heated to 385 °F (196 °C) and pressing it hard using a special tool for 10 seconds to flatten it. Burgers typically are not further pressed after they have begun to cook; once the patty is heated to the point that fat begins to melt, pressing the burger will squeeze the juices out and cause it to dry out. The technique caramelizes the bottom of the patty onto the buttered griddle and locks the juices into the burger, preventing them from escaping and marinating the burger in its own juices. Smashburger's smashing technique also lets it cook burgers in three minutes, where a traditional burger can take up to eight minutes to cook. During mealtime rushes, this also means customers cycle through the tables in the restaurant more quickly and each table can turn three successive groups of guests per hour instead of two.
complete encasement in concrete square column. wrapping the i-beam in a thin layer of metal lath and then covering it with gypsum plaster. This method is effective because gypsum plaster contains water crystals that are heat resistant. applying multiple layers of gypsum board around the i-beam. applying spray-on fireproofing around the i-beam. Also called spray-applied fire-resistive materials (SFRM) using air pressured spray gun, which can be made from gypsum plaster, mineral fibers mixed with inorganic binder or a cementitious formula using magnesium oxychloride cement. enclosing the i-beam in sheet metal and fill with loose insulation. hollow columns filled with liquid water or antifreeze. When part of the column is exposed to fire, the heat is dissipated throughout by the convection property of the liquid. encasing the i-beam in rigid concrete slab. a layer of suspended plaster ceiling isolating the i-beam
Sources: en.wikipedia.org
The vulva has a major role to play in the reproductive system. It provides entry to, and protection for the uterus, and the right conditions in terms of warmth and moisture that aids in its sexual and reproductive functions. The vulva is richly innervated and provides pleasure when properly stimulated. The mons pubis provides cushioning against the pubic bone during intercourse. A number of different secretions are associated with the vulva, including urine (from the urethral opening during urination through control of the external sphincter muscle), sweat (from the apocrine glands), menses (leaving from the vagina via the introitus), sebum (from the sebaceous glands), alkaline fluid (from the Bartholin's glands), mucus (from the Skene's glands), vaginal lubrication from the vaginal wall and smegma. Smegma is a white substance formed from a combination of dead cells, skin oils, moisture and naturally occurring bacteria, that forms in the genitalia. In females, this thickened secretion collects around the clitoris and labial folds. It can cause discomfort during sexual activity as it can cause the clitoral glans to stick to the hood, and is easily removed by bathing. Aliphatic acids known as copulins are also secreted in the vagina. These are believed to act as pheromones. Their fatty acid composition, and consequently their odor changes in relation to the stages of the menstrual cycle.
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=== China (mainland) === The National Administration of Traditional Chinese Medicine was created in 1949, which then absorbed existing TCM management in 1986 with major changes in 1998. China's National People's Congress Standing Committee passed the country's first law on TCM in 2016, which came into effect on 1 July 2017. The new law standardized TCM certifications by requiring TCM practitioners to (i) pass exams administered by provincial-level TCM authorities, and (ii) obtain recommendations from two certified practitioners. TCM products and services can be advertised only with approval from the local TCM authority. Ready-to-use TCM preparations, also known as Chinese patent medicines, are regulated by the National Medical Products Administration (and its predecessor CFDA) similar to preparations used in modern medicine since 1984. The barrier for entry, however, is much lower than medications based on modern/non-TCM principles; the rules allow for omitting clinical testing in a variety of circumstances. As of 2025, the latest (2020) rules allow a simplified procedure for preparations derived from an approved list of "classic prescriptions". The government-run healthcare system covers a number of TCM procedures and preparations. In 2021, a total of 7114.5 billion yuan went into healthcare, amounting for 6.59% of the year's national GDP. Of these, 1111.5 billion yuan went into covering costs associated with TCM preparations (0.97% of national GDP), with 592.4 billion yuan covering the actual medications.
In the cell membrane peptides fold into helices and sheets to allow the non-polar residues to interact with the membrane interior, and to allow the polar residues to be exposed to the aqueous environment. This self-assembly allows the peptides to further optimise their interaction with the surroundings. Peptide amphiphiles are very useful in biomedical applications, and can be utilised to act as therapeutic agents to treat diseases by transporting drugs across membranes to specific sites. They can then be metabolised into lipids and amino acids, which are then easily removed in the kidneys. This occurs by the hydrophobic tail being able to cross the cell membrane, allowing the peptide epitope to target a specific cell by a ligand- receptor complex. Other applications of peptide amphiphiles are use in antimicrobials, skincare and cosmetics, and also gene delivery to name a few.
Sources: en.wikipedia.org
The thrifty gene hypothesis postulates that, due to dietary scarcity during human evolution, people are prone to obesity. Their ability to take advantage of rare periods of abundance by storing energy as fat would be advantageous during times of varying food availability, and individuals with greater adipose reserves would be more likely to survive famine. This tendency to store fat, however, would be maladaptive in societies with stable food supplies. This theory has received various criticisms, and other evolutionarily based theories such as the drifty gene hypothesis and the thrifty phenotype hypothesis have also been proposed.
Jamaican vomiting sickness, also known as toxic hypoglycemic syndrome (THS), acute ackee fruit intoxication, or ackee poisoning, is an acute illness caused by the toxins hypoglycin A and hypoglycin B, which are present in fruit of the ackee tree. Unripe arils contain concentrations of hypoglycin A that are 20-fold higher than those of ripe arils. Vomiting is a symptom of a toxic encephalopathy which can result even in death. Some countries in the Caribbean and Western Africa experience frequent cases.
In lichenology, simple chemical spot tests are used to detect certain compounds in situ, and X. parietina yields clear results due to its anthraquinone pigments. A standard test is the K test (using potassium hydroxide solution). On X. parietina, applying KOH to the cortex produces a deep purple reaction (K+ purple). This is a classic indication of anthraquinones like parietin – the KOH causes parietin to form a purple salt (a distinctive color change). Other spot test results for this lichen are negative: C−, KC−, and P−. In addition to its anthraquinone pigments, Xanthoria parietina contains small amounts of calcium oxalate, a secondary metabolite that occurs in many lichens, particularly those growing on calcareous substrates. However, unlike strictly calcicolous species such as Caloplaca heppiana and Lecanora calcarea, which accumulate large quantities of calcium oxalate, X. parietina was found to contain only minor traces of this compound. This suggests that while X. parietina can tolerate limestone habitats, it does not rely on extensive oxalate production for calcium regulation or substrate modification to the same extent as obligate calcicoles.
Sources: en.wikipedia.org
Major regulatory agencies have not approved it for any indication. Some countries permit it only under prescription frameworks, while others classify it as a controlled substance.
Much of the evidence comes from case reports and accounts of unregulated use rather than controlled trials. Differences in product purity and dosing add further variability.
Laboratory work focuses on receptor binding and cellular signalling. Observational reports document outcomes after use, and analytical chemists examine samples to assess content and purity.
No. It is a synthetic analogue carrying four amino acid changes, a lactam ring and an amidated C-terminus. The natural hormone is a linear thirteen-amino-acid peptide processed from proopiomelanocortin.