This is a working overview of MC1R, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-04-12 and is reviewed periodically as new material appears.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C50H69N15O9 | Synthetic cyclic heptapeptide |
| Molecular mass | Approximately 1024 g/mol | Depends on counter-ion content |
| Appearance | White to off-white powder | Commonly supplied as a lyophilised solid |
| Solubility | Freely soluble in water | Also dissolves in common aqueous buffers |
| Typical storage | -20 degrees Celsius, desiccated | Protect from light and repeated freeze-thaw |
The compound emerged from research programs in the 1980s that examined analogues of alpha-melanocyte-stimulating hormone for pigmentation and photoprotection. Investigators modified the native sequence to extend activity duration and potency. A related analogue, afamelanotide, was developed within the same broad line of inquiry and eventually gained approval in certain jurisdictions for a rare light-sensitivity condition. Melanotan-2 itself did not progress through the same regulatory route and has no approved therapeutic indication.
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.
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.
Identity and purity are assessed with chromatographic and mass spectrometric techniques. Reversed-phase high-performance liquid chromatography separates the target peptide from related impurities and degradation products, and the resulting retention time is compared against a reference standard. Mass spectrometry, often coupled to liquid chromatography, confirms molecular mass. Amino acid analysis or peptide mapping can provide additional sequence-level confirmation when required. Results are only as reliable as the reference materials used alongside them.
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 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.
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.
Lyophilised peptide powder is comparatively stable when kept dry, cold and protected from light. Once dissolved, the molecule is exposed to hydrolysis, oxidation and microbial growth, and degradation accelerates at higher temperatures and in alkaline solution. Repeated freeze-thaw cycles concentrate solutes and promote aggregation. Handling guidance for research peptides commonly clusters around freezer temperatures for powder and short refrigerated use for reconstituted solutions, with pH control and sterile technique applied throughout.
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.
== Theory == The formation of a complex between a metal ion, M, and a ligand, L, is in fact usually a substitution reaction. For example, in aqueous solutions, metal ions will be present as aqua ions, so the reaction for the formation of the first complex could be written as
Imine-based cages aressusceptible to hydrolysis, which could be exploited for controlled release applications. boronic ester groups, which are known to bind diols could be used to recognize sugar analytes. Post-synthetic modification of cage structures is also possible.
Southern African Association of Freight Forwarders (SAAFF) Chartered Institute of Logistics and Transport (CILT) International Federation of Freight Forwarders Associations (IFFFA) The Fuels Industry Association of South Africa (FIASA) Road Freight Association (RFA) SAPICS South African Express Parcel Association (SAEPA) South African Association of Ship Operators and Agents (SAASOA) African Rail Industry Association (ARIA) Commercial Aviation Association of Southern Africa (CAASA) Fresh Produce Exporters' Forum (FPEF)
Gallrein served in the U.S. military for three decades, from 1984 to 2014, serving with U.S. Navy SEAL Team Six. He rose to the rank of Navy captain, as he was deployed to Panama, Afghanistan, Iraq, and the Persian Gulf. He was inspired to join the military by President Ronald Reagan. By November 1985, Gallrein had become an ensign in the United States Navy and was stationed at Little Creek Naval Amphibious Base. During his 2026 political campaign, Gallrein said that he had received four Bronze Star Medals; Gallrein was awarded three—the fourth appears to be the bronze star on his Combat Parachutist Badge. He also has two Presidential Unit Citations. After his military career, Gallrein turned to becoming a dairy farmer and a business owner operating Circle G Farm and Stables in Shelby County since 2014.
"The fibrous variant of Hashimoto's thyroiditis" (1974, with Austin L. Vickery Jr.) "Thymoma in a 12-year-old boy" (1976, with Jane Chatten) "Urinary Ultrastructural Findings in Fabry Disease" (1977, with Patricia J. Lyons) "Examination of Sputum in Legionnaire's Disease" (1978) "Legionnaires' disease: structural characteristics of the organism" (1978, with Philip Nash) "Leydig cell tumors of the testis" (1979, with I. Damjanov and M. A. Jewett) "Ultrastructural Features of Respiratory Cilia in Cystic Fibrosis" (1980, with Douglas S. Holsclaw Jr.) "Postinflammatory pseudotumors of the lung: fibrous histiocytoma and related lesions" (1980, with E. E. Schwartz and G. A. Mandell) "Tolmetin: Association With Reversible Renal Failure and Acute Interstitial Nephritis" (1981, with Ralph Capaldo, Erich A. Everts, and John G. DiGregorio) "Pleomorphism of Legionella pneumophila" (1984, with Shahab Hashemi, Kristy R. Brown, William A. Habib, and Jay M. Hammel) "Cilia in the Human Kidney" (1984, with Joseph J. Morgan) Legionellosis (1985) "Microscopic Nephrocalcinosis in Cystic Fibrosis" (1988, with Leslie J. Krueger and Bonita L. Falkner) "A Self-Limited Febrile Illness Produced in Guinea Pigs Associated With Oral Administration of Legionella pneumophila" (1988, with Jay M. Hammel, Joseph P. Matus, Ronald Poropatich, and Julian Katz) "Diagnostic value of electron microscopy on paraffin-embedded cytologic material" (1993, with Nancy A. Young and Sonya Naryshkin)
Sources: en.wikipedia.org
Phalloidin belongs to a class of toxins called phallotoxins, which are found in mushrooms of the genus Amanita. It is a rigid bicyclic heptapeptide that is lethal after a few days when injected into the bloodstream. The major symptom of phalloidin poisoning is acute hunger due to the destruction of liver cells. It functions by binding and stabilizing filamentous actin (F-actin) and effectively prevents the depolymerization of actin fibers. Due to its tight and selective binding to F-actin, derivatives of phalloidin containing fluorescent tags are used widely in microscopy to visualize F-actin in biomedical research.
The fibrous rings surrounding the arterial orifices serve for the attachment of the great vessels and semilunar valves, they are known as The aortic annulus. Each ring receives, by its ventricular margin, the attachment of some of the muscular fibers of the ventricles; its opposite margin presents three deep semicircular notches, to which the middle coat of the artery is firmly fixed. The attachment of the artery to its fibrous ring is strengthened by the external coat and serous membrane externally, and by the endocardium internally. From the margins of the semicircular notches, the fibrous structure of the ring is continued into the segments of the valves. The middle coat of the artery in this situation is thin, and the vessel is dilated to form the sinuses of the aorta and pulmonary artery.
Pyridinoline, also known as Hydroxylysylpyridinoline, is a fluorescent cross-linking compound of collagen fibers. Crosslinks in collagen and elastin are derived from lysyl and hydroxylysyl residues, a process catalyzed by lysyl oxidase. Fujimoto and colleagues first described the isolation and characterization of a fluorescent material in bovine Achilles tendon collagen and termed it pyridinoline. It is reported to be present in collagen of bone and cartilage, but is absent in collagen of skin. It is not present in newly synthesized collagen and is formed from aldimine cross-links during maturation of collagen fibers. Pyridinoline and deoxypyridinoline were found to be released into the blood during bone degradation and rapidly excreted in the urine. In a preliminary study, both these compounds were proposed as a marker for metastatic bone tumor in patients with prostate cancer.
Nobelium (102No) is a synthetic element, and thus a standard atomic weight cannot be given. Like all synthetic elements, it has no stable isotopes. The first isotope to be synthesized (and correctly identified) was 254No in 1966. There are fourteen known radioisotopes, which are 248No to 260No and 262No, and many isomers. The longest-lived isotope is 259No with a half-life of 58 minutes. The longest-lived isomer is 251m1No with a half-life of 1.02 seconds.
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As the tepid reaction to the German Anschluss with Austria had shown, the governments of France, the United Kingdom and Czechoslovakia were set on avoiding war at any cost. The French government did not wish to face Germany alone and took its lead from the British government, led by Prime Minister Neville Chamberlain. He contended that Sudeten German grievances were justified and believed that Hitler's intentions were limited. That made Britain and France advise Czechoslovakia to concede to the German demands. Beneš resisted, and on 20 May 1938, a partial mobilisation was under way in response to the possible German invasion. It is suggested that the mobilisation could have been launched on basis of Soviet misinformation about Germany being on verge of invasion, which aimed to trigger war in Western Europe. On 30 May, Hitler signed a secret directive for war against Czechoslovakia to begin no later than 1 October. In the meantime, the British government demanded for Beneš to request a mediator. Not wishing to sever his government's ties with Western Europe, Beneš reluctantly accepted. The British appointed Lord Runciman and instructed him to persuade Beneš to agree to a plan acceptable to the Sudeten Germans. On 2 September, Beneš submitted the Fourth Plan, which granted nearly all of the demands of the Karlsbader Programm. Intent on obstructing conciliation, however, the SdP held demonstrations that provoked the police in Ostrava on 7 September. The Sudeten Germans broke off negotiations on 13 September, and violence and disruption ensued.
Diallyl disulfide (DADS or 4,5-dithia-1,7-octadiene) is an organosulfur compound derived from garlic and a few other plants in the genus Allium. Along with diallyl trisulfide and diallyl tetrasulfide, it is one of the principal components of the distilled oil of garlic. It is a yellowish liquid which is insoluble in water and has a strong garlic odor. It is produced during the decomposition of allicin, which is released upon crushing garlic and other plants of the family Alliaceae. Diallyl disulfide has many of the health benefits of garlic, but it is also an allergen causing garlic allergy. Highly diluted, it is used as a flavoring in food. It decomposes in the human body into other compounds such as allyl methyl sulfide.
On 1 February 2022, congressman Héctor Valer was appointed to succeed Mirtha Vásquez, who had resigned the previous day after denouncing corruption and a lack of consensus within her cabinet and with Pedro Castillo. Valer was a controversial figure, facing difficulties in his duties due to a 2016 allegation of violence made by his wife and daughter, which he denied. All parliamentary groups refused to grant him a vote of confidence, including the governing coalition, and two ministers opposed his appointment. Pedro Castillo was forced to react and announced a cabinet reshuffle. On 5 February 2022, Héctor Valer resigned following the resurfacing of past domestic violence allegations, marking the shortest-lived cabinet since 1980. However, he continued to serve in an interim capacity while the government awaited the appointment of his successor.
Sources: en.wikipedia.org
It is a synthetic cyclic heptapeptide and an analogue of alpha-melanocyte-stimulating hormone. The molecule is produced by chemical synthesis rather than extracted from a biological source.
It is shorter than the native hormone and carries a cyclic constraint that improves stability. These changes raise receptor potency and slow breakdown relative to the naturally occurring peptide.
Published accounts date its development to the 1980s, when researchers were generating analogues of melanocyte-stimulating hormone. That work aimed to produce more stable compounds for studying pigmentation biology.
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.