This is a working overview of melanocortin receptor, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-02-26 and is reviewed periodically as new material appears.
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.
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.
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.
| 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.
Regulatory treatment varies by country. In the United States, melanotan-2 is not approved for any indication, and products marketed for human use fall outside the approved drug framework. Some other jurisdictions have placed it under prescription controls or listed it as a prohibited or restricted substance. Online listings frequently describe the material as a research chemical, a category that does not carry the same manufacturing and labelling requirements as approved medicines.
Solid peptide material is generally stable when kept cold and dry. Common practice is storage at -20 degrees Celsius or lower, with desiccant and protection from light. Repeated freeze-thaw cycles and exposure to moisture are associated with degradation, aggregation, or loss of material. Once dissolved, stability depends on solvent, concentration, and temperature, and solutions are usually treated as short-lived unless stability data support longer periods. Handling notes typically emphasise minimising time at ambient temperature.
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.
An initial tree, Ti, is randomly selected. A neighbour tree, Tj, is selected from the collection of trees. The ratio, R, of the probabilities (or probability density functions) of Tj and Ti is computed as follows: R = f(Tj)/f(Ti) If R ≥ 1, Tj is accepted as the current tree. If R < 1, Tj is accepted as the current tree with probability R, otherwise Ti is kept. At this point the process is repeated from Step 2 N times. The algorithm keeps running until it reaches an equilibrium distribution. It also assumes that the probability of proposing a new tree Tj when we are at the old tree state Ti, is the same probability of proposing Ti when we are at Tj. When this is not the case Hastings corrections are applied. The aim of Metropolis-Hastings algorithm is to produce a collection of states with a determined distribution until the Markov process reaches a stationary distribution. The algorithm has two components:
From the mesoderm surrounding the neural tube and notochord, the skull, vertebral column, and the membranes of the brain and medulla spinalis are developed. Because it originates from the primitive node and is ultimately positioned with the mesodermal space, it is considered to be derived from mesoderm. A postembryonic vestige of the notochord is found in the nucleus pulposus of the intervertebral discs. Isolated notochordal remnants may escape their lineage-specific destination in the nucleus pulposus and instead attach to the outer surfaces of the vertebral bodies, from which notochordal cells largely regress.
For example, metro stations in Pyongyang, North Korea, were constructed 110 metres (360 ft) below ground, and were designed to serve as nuclear shelters in the event of war, with each station entrance built with thick steel blast doors. An example of privately funded fallout shelters is the Ark Two Shelter in Ontario, Canada, and autonomous shelters have been constructed with an emphasis on post-war networking and reconstruction. In Switzerland, the majority of homes have an underground blast and fallout shelter. The country has an overcapacity of such shelters and can accommodate slightly more than the nation's population size. While the nuclear fallout shelters described above are the ideal long-term protection methods against dangerous radiation exposure in the event of a nuclear catastrophe, it is also necessary to have mobile protection equipment for medical and security personnel to safely assist in containment, evacuation, and many other necessary public safety objectives which ensue as a result of nuclear detonation. There are many basic shielding strategies used to protect against the deposition of radioactive material from external radiation environments. Respirators that protect against internal deposition are used to prevent the inhalation and ingestion of radioactive material and dermal protective equipment which is used to protect against the deposition of material on external structures like skin, hair, and clothing.
=== Wnt signaling === In 2012, Garcia's laboratory determined the crystal structure of a Wnt protein in complex with its cellular receptor, Frizzled. The Wnt-Frizzled structure indicated that Wnts utilize a post-translational lipid modification to directly engage the Frizzled extracellular domain, which represents a highly unusual binding mode among soluble ligands. Garcia's study revealed a striking, donut-shaped architecture adopted by the Wnt-Frizzled complex that adorns the cover of the July 6th, 2012 issue of Science. More recently, Garcia's laboratory reported a breakthrough in being able to recapitulate canonical Wnt signaling using water-soluble bispecific ligands that dimerize Frizzled and Lrp6, which has important implications for the development of therapeutics for regenerative medicine.
Bovine somatotropin or bovine somatotrophin (abbreviated bST and BST), or bovine growth hormone (BGH), is a peptide hormone produced by cows' pituitary glands. Like other hormones, it is produced in small quantities and is used in regulating metabolic processes. Recombinant bovine somatotropin (usually "rBST") is a synthetic version of the bovine growth hormone given to dairy cattle by injection to increase milk production. BST increases milk production by around 10 percent. Controversy over its safety for cows has led to rBST being banned in several countries, including the European Union since 1990, and Canada, Japan, Pakistan, Australia, New Zealand, and Argentina, as it has been found to increase health risks in cows. The Codex Alimentarius has not approved it as safe. The FDA approved it in 1993 and gave guidance to manufacturers that marking a product as "bST-free" or "rbST free" is misleading and a less misleading text would be "No significant difference has been shown between milk derived from rbST-treated and non-rbST-treated cows".
Sources: en.wikipedia.org
About 21,000 were raised in the First World War, mainly consisting of Sikhs of Punjab and Rajputs from Rajputana (such as the Bikaner Camel Corps and the Hyderabad, Mysore and Jodhpur Lancers of the Imperial Service Cavalry Brigade). These forces played a prominent role in the Sinai and Palestine Campaign.
Studies have found prolonged viability of bacteria on stainless-steel surfaces at room temperature. In a specific study, stainless steel was inoculated with 107 CFU/cm2 E. coli and K. pneumoniae, containing blaCTX-M-15 and blaNDM-1 (antibiotic-resistant genes) respectively. Thirty days later (at room temperature, 22˚ C), 104 viable cells remained; and, after 100 days, 100 CFU/cm2 of E. coli remained. In contrast, on copper and copper alloy surfaces, rapid death of antibiotic-resistant bacterial strains, as well as destruction of plasmid and genomic DNA, can be observed. Studies suggest that exposure to dry copper surfaces inhibits the respiration and growth of producers by releasing copper ions. Increased horizontal gene transfer (HGT) is observed simultaneously with cell viability on stainless steel surfaces. HGT is one of the major factors responsible for creating antibiotic resistance in bacteria. This suggests that immediate decontamination of surfaces is important in preventing the spread of antibiotic resistance genes. It has also been shown that horizontal transfer of antibiotic-resistant β-lactamase genes does not occur on antimicrobial copper surfaces. As copper surfaces degrade naked DNA (and plasmid DNA in antibiotic-resistant E. coli and K. pneumoniae), copper surfaces would halt HGT. Horizontal gene transfer has been demonstrated to occur readily on dry surfaces such as stainless steel, but not on copper and copper alloy surfaces. The rate of bacterial death increased proportionally with the percentage of copper in the copper alloy surface.
== External links == SIPG, Shanghai International Port (Group) Co., Ltd Entry in MarineTraffic PortFinder – database of information about the port CNSHG – its United Nations location code VesselFinder – database of ships currently in the port Entry in the World Port Index database
== Management == There is no cure for Alzheimer's disease; available treatments offer relatively small symptomatic benefits but remain palliative in nature. Treatments can be divided into pharmaceutical, psychosocial, and caregiving.
Sources: en.wikipedia.org
=== US marketing scheme === In the 1980s, the Jerusalem artichoke also gained some notoriety when its seeds were planted by Midwestern US farmers at the prodding of an agricultural attempt to save the family farm. This effort aimed to teach independent farmers to raise their own food, feed, and fuel. Little market existed for the tuber in that part of the US then, but contacts were made with sugar producers, oil and gas companies, and the fresh food market for markets to be developed. Fructose had not yet been established as a mainstay, nor was ethanol used as a main fuel additive as it is today. The only real profit in this effort was realized by a few first-year growers (who sold some of their seed to other farmers individually as well as with the help of the company attempting this venture). As a result, many of the farmers who had planted large quantities of the crop lost money.
South Korean president Lee Jae Myung criticized the campaign via X, stating that it insulted the victims and the residents of Gwangju. Starbucks Korea apologized and its CEO, Son Jeong-Hyun, was fired. Starbucks Korea planned to shutter all its stores in South Korea for half a day on June 22 for its staff to attend a history lesson to increase historical awareness and social sensitivities.
As scientists discover more about Earth, vast numbers of positive and negative feedback loops are being discovered,, that, together, maintain a metastable condition, sometimes within a very broad range of environmental conditions.
=== Road paving === Asphalt modification through nanoparticles can be considered as an interesting low-cost technique in asphalt pavement engineering providing novel perspectives in making asphalt materials more durable.
The Malaysian Armed Forces has three branches: the Malaysian Army, Royal Malaysian Navy and the Royal Malaysian Air Force. There is no conscription, and the required age for voluntary military service is 18. The military uses 1.5% of the country's GDP, and employs 1.23% of Malaysia's manpower. Malaysian peacekeeping forces of MALBATT have contributed to many U.N. peacekeeping missions, such as in Congo, Iran–Iraq, Namibia, Cambodia, Bosnia and Herzegovina, Somalia, Kosovo, East Timor, and Lebanon. The Five Power Defence Arrangements is a regional security initiative that has been in place for almost 40 years. It involves joint military exercises held among Malaysia, Singapore, Australia, New Zealand, and the United Kingdom. Joint exercises and war games have also been held with Brunei, China, India, Indonesia, Japan, and the United States. Malaysia, Philippines, Thailand, and Vietnam have agreed to host joint security force exercises to secure their maritime border and tackle issues such as illegal immigration, piracy, and smuggling. Previously there were fears that extremist militant activities in the Muslim areas of the southern Philippines and southern Thailand would spill over into Malaysia. Because of this, Malaysia began to increase its border security.
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.
Mass spectrometry combined with liquid chromatography provides both molecular weight confirmation and a measure of related impurities. Tandem mass spectrometry adds sequence information. A purity percentage reported without a mass measurement does not confirm what the material is.