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 2025-12-04. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
Early published reports described melanotan-2 as a tanning agent without sun protection, which means darkening is not the same as protection against ultraviolet radiation. Later studies explored the peptide in erectile dysfunction, hemorrhagic shock, and some skin conditions. No regulator in the United States or Europe has approved it for clinical use. Many products labelled melanotan-2 are sold without approval and their identity and purity are unverified. Its long-term safety in humans remains an open question.
| 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 |
Melanotan-2 is frequently confused with afamelanotide, a linear analogue authorised in the European Union for erythropoietic protoporphyria. The two compounds differ in chain length, ring structure and receptor selectivity, so findings for one cannot be transferred directly to the other. Published controlled human data on melanotan-2 remain sparse, and much of what circulates online derives from small studies or unpublished reports. Questions about effect size, dose-response behaviour and long-term safety therefore remain unresolved.
Melanotan-2 is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone. Its sequence incorporates a lactam bridge that constrains the peptide into a ring, which increases resistance to enzymatic breakdown relative to the natural hormone. Researchers at the University of Arizona synthesised the compound in the late 1980s and early 1990s while studying pigmentation pathways. It has never received marketing approval from any national medicines regulator. In the scientific literature it is usually described as a laboratory research reagent rather than a therapeutic product.
Melanocortin receptors comprise five subtypes with distinct tissue distributions and functions. Melanotan-2 is described in the literature as a non-selective agonist that engages several of these subtypes, including MC1R, MC3R, MC4R, and MC5R. MC1R is the subtype most directly linked to melanin production in skin cells. Because the compound is not subtype-selective, its observed effects in experimental settings are generally attributed to activity across multiple receptor pathways rather than to a single target.
Melanotan-2 is a synthetic linear peptide built from seven amino acids arranged in a short chain. Its sequence is commonly written as Ac-Nle-Asp-His-D-Phe-Arg-Trp-Lys-NH2, which includes a modified N-terminus and an amidated C-terminus. The molecule belongs to the melanocortin family and acts as a receptor agonist. Structural features such as the D-phenylalanine residue and the Nle substitution are associated with increased stability against enzymatic degradation relative to the natural parent peptide.
Renata Rodrigues produced an informative study detailing both the proteome and the transcriptome of the Neuwied's Lancehead (Bothropoides pauloensis), with all the methods described above. The proteome showed the presence of nine protein families with the majority of components belonging to snake venom metalloproteinases (38%), phospholipase A2 (31%) and Bradykinin-potentiating peptides/C-type natriuretic peptides (12%). The transcriptome gave a cDNA of over 1100 expressed sequence tags (ESTs), with only 688 sequences being related to the venom gland. Similarly, the transcriptome showed matching results with 36% of SVMP's being the majority of the ESTs followed by PLA2 (26%) and BPP/C-NP (17%) sequences. Furthermore, this study shows that through both the use of proteomic and transcriptomics, we can fully comprehend the components within venom. This can then lead to both the molecular structure and functions of many bioactive components, which can in turn lead to bioprospecting venom components into new medicines and can help to develop better methods of creating anti-venoms.
Scarborough (; 2021 Census 623,610) is a district of Toronto, Ontario, Canada, situated in the eastern part of Toronto. Its borders are Victoria Park Avenue to the west, Steeles Avenue and the city of Markham to the north, Rouge River and the city of Pickering to the east, and Lake Ontario to the south. Scarborough was named after the English town of Scarborough, North Yorkshire, inspired by its cliffs. Scarborough is the site of several former Indigenous settlements dating back many centuries. It was settled by Europeans in the 1790s and has grown from a collection of small rural villages and farms to become a fully urbanized and diverse cultural community. Incorporated in 1850 as a township, the district became part of Metropolitan Toronto in 1953 and was reconstituted as a borough in 1967. The borough rapidly developed as a suburb of Toronto over the next decade and became a city in 1983. In 1998, the city and the rest of Metropolitan Toronto were amalgamated into the present city of Toronto. The Scarborough Civic Centre – the former city's last seat of government – now houses offices of the municipal government of Toronto. Since the end of the Second World War, the district has been a popular destination for new immigrants in Canada. As a result, it is one of the most diverse and multicultural areas in the Greater Toronto Area, being home to various religious groups and places of worship. It includes a number of natural landmarks, including the Toronto Zoo, Rouge Park, and the Scarborough Bluffs.
== Protein == Human corin, a polypeptide of 1042 amino acids, consists of an N-terminal cytoplasmic domain, a transmembrane domain and an extracellular region with two frizzled-like domains, eight LDL receptor-like domains, a scavenger receptor-like domain and a C-terminal trypsin-like serine protease domain. Corin is synthesized as a zymogen that is activated by PCSK6. Corin exhibits a trypsin-like catalytic activity favoring basic residues at the P1 position. Human corin contains 19 N-glycosylation sites. N-glycans promote corin expression on the cell surface and protect corin from metalloproteinase-mediated shedding.
Primary reconstruction: to correct the breast hemisphere by repairing chest-and-breast tissues damaged by breast cancer, by blunt trauma and penetrating trauma, by a blast injury, and the failed anatomic development of the chest, such as a tuberous breast deformity. Revision and reconstruction: to correct the unsuccessful outcome of a previous mammoplasty procedure. Primary augmentation: to enhance the aesthetic qualities of the breasts (cup-size, form, and texture). The type of breast reconstruction approach is determined by the severity of the mastectomy. The type of breast-augmentation surgery is determined by the procedure for emplacing the prosthetic breasts, the type of surgical incision, the type and model of the prosthetic breast, and the location of the implant-pocket in the chest of the woman.
Sources: en.wikipedia.org
It also condemned Israel's attacks on Syrian territory and its "continued violations of international laws and norms". Hamas: Hamas issued a statement expressing full solidarity with Syria and described the Israeli attacks as a "blatant violation of international laws" and called for a strong response to confront them. Hezbollah: Hezbollah condemned the Israeli strikes, describing them as against international law.
== Top CROs by annual revenue == As of 2016, there was a 15.5% increase in R&D spending from 2015 to 2020. The list of contract research organizations includes the following notable companies worldwide:
== Uses == TCFH itself is a common reagent used in the preparation of uronium and guanidinium salts used for amide bond formation and peptide synthesis, such as HATU. Amide bond formation with TCFH can be performed in a wide range of organic solvents, most commonly acetonitrile, but also water and in the solid state. Reactions typically require an added Brønsted base, and a wide range can be employed including N,N-diisopropylethylamine (DIPEA). In reactions of carboxylic acids with TCFH and a weakly Lewis basic amine like DIPEA, formation of an acid chloride or anhydride as the active acylating agent occurs. Use of N-methylimidazole (NMI) as a base, with both Brønsted and Lewis basic properties, provides some unique advantages. Reactions of carboxylic acids with TCFH and a strongly Lewis basic amine like NMI lead to in situ formation of an N-acyl imidazolium ion (NAI) as the active acylating agent.
== Side effects == Possible and rare side effects may include dizziness, hypotension, indigestion, allergic reactions (itchy skin) after high doses, hypothermia, fatigue. And lowered blood pressure and/or body temperature decreased by 1 to 1.5 °C. Blood pressure and body temperature return to normal after completion of treatment.
He earlier announced that his administration would not deport unaccompanied migrant children; the rise in arrivals of such children exceeded the capacity of facilities meant to shelter them, leading the Biden administration in March to direct the Federal Emergency Management Agency to help. On April 14, Biden announced that the United States would delay the withdrawal of all troops from the war in Afghanistan until September 11, signaling an end to the country's direct military involvement in Afghanistan after nearly 20 years. In February 2020, the Trump administration had made a deal with the Taliban to completely withdraw U.S. forces by May 1, 2021. Biden's decision met with a range of reactions, from support and relief to trepidation at the possible collapse of the Afghan government without American support. On April 22–23, Biden held an international climate summit at which he announced that the U.S. would cut its greenhouse gas emissions by 50%–52% by 2030 compared to 2005 levels. On April 28, the eve of his 100th day in office, Biden delivered his first address to a joint session of Congress.
Sources: en.wikipedia.org
There are evidence-based indications for using antipsychotics in children (e.g., tic disorder, bipolar disorder, psychosis), but the use of antipsychotics outside of those contexts (e.g., to treat behavioral problems) warrants significant caution. Antipsychotics are used to treat tics associated with Tourette syndrome. Aripiprazole, an atypical antipsychotic, is used as add-on medication to ameliorate sexual dysfunction as a symptom of selective serotonin reuptake inhibitor (SSRI) antidepressants in women. Quetiapine is used to treat generalized anxiety disorder.
ATP synthase, also called complex V, is the final enzyme in the oxidative phosphorylation pathway. This enzyme is found in all forms of life and functions in the same way in both prokaryotes and eukaryotes. The enzyme uses the energy stored in a proton gradient across a membrane to drive the synthesis of ATP from ADP and phosphate (Pi). Estimates of the number of protons required to synthesize one ATP have ranged from three to four, with some suggesting cells can vary this ratio, to suit different conditions.
The Spanish navy had been totally dismantled by a disastrous naval policy and relegated to the background by the urgency of the war against Napoleon itself. To 1817, Tsar Alexander supported reactionary governments. Ferdinand VII applied to the Tsar to purchase vessels. The Tsar agreed to this request with the offer of the sale of some of his own vessels. The agreement was finally negotiated at Madrid, between Dmitry Tatishchev, Russian ambassador, and Eguia, Minister of war. It was apparently known only to these two, and to the king himself. The text of the treaty of sale has not been found in the Spanish naval archives. This diplomatic transaction was veiled in the deepest secrecy against Spanish Navy and Minister of Navy. The requested fleet would consist of 5 warships and 3 frigates. The squadron would be delivered to Cadiz, duly armed, and supplied. The arrival of the Russian fleet in Cadiz in February 1818 was not to the liking of the Spanish navy, which was dissatisfied with the state of deterioration in which some supposedly new ships were found: between 1820 and 1823 all the warships were scrapped as being useless. This fiasco put an end to the whole plan to reconquer the Rio de la Plata, which would end with the uprising of the Spanish Army in Cadiz (Trienio Liberal). In 1818 one of the frigates (Maria Isabel aka Patrikki) was captured in the Pacific, after the uprising of one of the Spanish troop transports that went over to the side of the American rebels delivering all the keys, routes and signals for the capture of the frigate.
=== Population structure === The population of P. aeruginosa can be classified in three main lineages, genetically characterised by the model strains PAO1, PA14, and the more divergent PA7. While P. aeruginosa is generally thought of as an opportunistic pathogen, several widespread clones appear to have become more specialised pathogens, particularly in cystic fibrosis patients, including the Liverpool epidemic strain (LES) which is found mainly in the UK, DK2 in Denmark, and AUST-02 in Australia (also previously known as AES-2 and P2). There is also a clone that is frequently found infecting the reproductive tracts of horses.
=== Diffusive === Some materials may merge at the joint by diffusion. This may occur when the molecules of both materials are mobile and soluble in each other. This would be particularly effective with polymer chains where one end of the molecule diffuses into the other material. It is also the mechanism involved in sintering. When metal or ceramic powders are pressed together and heated, atoms diffuse from one particle to the next. This joins the particles into one.
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.
No. It is a laboratory-made peptide, while the natural hormone is alpha-melanocyte-stimulating hormone, a longer peptide produced by the pituitary gland and by skin cells. Melanotan-2 mimics only a short active region of that hormone and contains non-natural residues such as D-phenylalanine.