MC1R comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Last reviewed on 2026-02-12. Where a claim depends on a specific study, the study is described rather than over-claimed.
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controlled human data on melanotan-2 remain sparse, and much of what circulates online derives from small studies or unpublished reports.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.
The peptide acts as a non-selective agonist at melanocortin receptors, showing affinity for MC1R, MC3R, MC4R and MC5R. Activation of MC1R on melanocytes drives the conversion of tyrosine into melanin and shifts production toward the darker eumelanin form. MC4R signalling in the central nervous system is linked to appetite and energy balance, which helps explain why reduced food intake appeared in early human studies. Effects on MC4R and on vascular tone also account for the erectile responses recorded as unexpected findings in those same trials.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic cyclic heptapeptide | Alpha-MSH analogue with a lactam ring |
| Molecular formula | C50H69N15O9 | Commonly cited value for the neutral peptide |
| Molecular weight | 1024.18 g/mol | Calculated for the free molecule |
| Appearance | White to off-white powder | Typically supplied as a lyophilised solid |
| Solubility | Soluble in water, DMSO and ethanol | Dissolution in pure water is often slow |
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.
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.
Melanotan II binds several melanocortin receptor subtypes rather than a single target. MC1R on melanocytes drives melanin synthesis, while MC3R and MC4R participate in energy balance, appetite, and sexual response pathways. This lack of selectivity explains why reported effects extend beyond skin darkening. Substitutions at positions four and seven, including norleucine and D-phenylalanine, increase potency and resistance to peptidases. Understanding which receptor mediates which effect remains an active area of investigation.
Published human data come mostly from small, short studies rather than large controlled trials. Reported outcomes include increased skin pigmentation and, in some reports, effects on appetite and libido, but sample sizes are small and follow-up is limited. Whether long-term use produces durable pigment changes or adverse effects is not established. Because products sold outside pharmacies are not standardized, the actual content of any given vial is often unknown. Independent testing of such material is uncommon.
Melanotan II is a synthetic cyclic heptapeptide analog derived from the core sequence of alpha-melanocyte-stimulating hormone. Researchers at the University of Arizona synthesized it during the 1980s while studying pigmentation and appetite signaling. The compound is not an approved medicine in any major jurisdiction and appears mainly in laboratory and research-chemical settings. Its structure incorporates a lactam bridge between side chains, which constrains the ring and slows enzymatic breakdown relative to the natural hormone.
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.
=== Purification === There are several methods for purifying and isolating honokiol. In nature, honokiol exists with its structural isomer magnolol, which differs from honokiol only by the position of one hydroxyl group. Because of the very similar properties of magnolol and honokiol, purification has often been limited to a HPLC or electromigration. However, methods developed in 2006 by workers in the lab of Jack L. Arbiser, took advantage of the proximity of the phenolic hydroxyl groups in magnolol, which form a protectable diol, to generate a magnolol acetonide (Figure 1), with a subsequent simple purification via flash chromatography over silica. Figure 1
== Plot == Half Bad is set in a version of modern-day Europe, mainly Britain, in which witches and humans (Fains) live together. Witches are divided into Black (oppressed and written off as evil), and White, the latter making up the majority of the witch population. The 17-year-old protagonist, Nathan, is half White and half Black, or Half Code. His mother is dead, and his father, Marcus, is the most powerful and violent Black witch in history. Because of his parentage, Nathan's every move is monitored by the Council of White Witches. He is forced to follow a strict set of rules, but when he breaks one too many, he is taken away from his grandmother and entrusted into the care of a White witch, Celia. Trapped in a cage and abused by Celia, Nathan must escape before his seventeenth birthday, to find his father, and receive three gifts from him and his Gift. Otherwise, he will die.
Support for teens (archive) University of Maryland guide to puberty and adolescence Growing Up Sexually: A World Atlas Pictures and detailed information about breast development during puberty Puberty in females: interactive animation of Tanner stages Puberty in males: interactive animation of Tanner stages
The Federation of Malaya Legislative Council held its first meeting in the Tuanku Abdul Rahman Hall, Kuala Lumpur in 1948. It was opened by the British high commissioner Sir Edward Gent. Attendees included the British minister of state for colonial affairs, Lord Listowel. The membership of the council was structured to include:
Sources: en.wikipedia.org
Austria signed the Treaty of Pressburg (26 December 1805) and left the coalition. The treaty required the Austrians to give up Venetia to the French-dominated Kingdom of Italy and the Tyrol to Bavaria. With the withdrawal of Austria from the war, stalemate ensued. Napoleon's army had a record of continuous unbroken victories on land, but the full force of the Russian army had not yet come into play. Napoleon had now consolidated his hold on France, had taken control of Belgium, the Netherlands, Switzerland, and most of Western Germany and northern Italy. His admirers say that Napoleon wanted to stop now, but was forced to continue in order to gain greater security from the countries that refused to accept his conquests. Esdaile rejects that explanation and instead says that it was a good time to stop expansion, for the major powers were ready to accept Napoleon as he was:
== Function == The protein encoded by this gene is an adaptor protein which contains five LIM domains, or double zinc fingers. The protein is likely involved in integrin signaling through its LIM domain-mediated interaction with integrin-linked kinase, found in focal adhesion plaques. It is also thought to act as a bridge linking integrin-linked kinase to NCK adaptor protein 2, which is involved in growth factor receptor kinase signaling pathways. Its localization to the periphery of spreading cells also suggests that this protein may play a role in integrin-mediated cell adhesion or spreading.
=== G04BX Other urologicals === G04BX01 Magnesium hydroxide G04BX03 Acetohydroxamic acid G04BX06 Phenazopyridine G04BX10 Succinimide G04BX11 Collagen G04BX12 Phenyl salicylate G04BX13 Dimethyl sulfoxide G04BX14 Dapoxetine G04BX15 Pentosan polysulfate sodium G04BX16 Tiopronin G04BX17 Sodium salicylate and methenamine QG04BX56 Phenazopyridine, combinations QG04BX90 Ephedrine QG04BX91 Phenylpropanolamine
For the correction of male breast defects and deformities, the pectoral implant is the breast prosthesis used for the reconstruction and the aesthetic repair of a man's chest wall (see: gynecomastia and mastopexy).
== History == Bovine pancreatic ribonuclease became a common model system in the study of proteins largely because it was extremely stable and could be purified in large quantities. In the 1940s Armour and Company purified a kilogram of protein - a very large quantity, particularly by the protein purification standards of the time - and offered samples at low cost to interested scientists. The ability to have a single lot of purified enzyme made it a predominant model system for protein studies. It remains commonly referred to as ribonuclease A or RNase A as the most prominent member of its protein family, known variously as pancreatic ribonuclease, ribonuclease A, or ribonuclease I. Christian Anfinsen's studies of the oxidative folding process of bovine pancreatic ribonuclease laid the groundwork for understanding the relationship between amino acid sequence and a protein's folded three-dimensional structure and solidified the thermodynamic hypothesis of protein folding, according to which the folded form of a protein represents its free energy minimum. RNase A was the first enzyme for which a correct catalytic mechanism was proposed, even before its structure was known. RNase A was the first protein for showing the effects of non-native isomers of peptide bonds preceding proline residues in protein folding.
Sources: en.wikipedia.org
Generally capillaries of smaller inner diameter support use of higher field strengths, due to improved heat dissipation and smaller thermal gradients relative to larger capillaries, but with the drawbacks of lower sensitivity in absorbance detection due to shorter path length, and greater difficulty in introducing buffer and sample into the capillary (small capillaries require greater pressure and/or longer times to force fluids through the capillary). The efficiency of capillary electrophoresis separations is typically much higher than the efficiency of other separation techniques like HPLC. Unlike HPLC, in capillary electrophoresis there is no mass transfer between phases. In addition, the flow profile in EOF-driven systems is flat, rather than the rounded laminar flow profile characteristic of the pressure-driven flow in chromatography columns as shown in figure 5. As a result, EOF does not significantly contribute to band broadening as in pressure-driven chromatography. Capillary electrophoresis separations can have several hundred thousand theoretical plates.
=== Broadcast and streaming === American Horror Story: 13 premiered at the Hotel Chelsea in New York City on September 23, 2026. On September 24, 2026, the season premiered on FX in the United States. The first two weeks are set to feature three episodes each, while the following weeks will feature two episodes at a time. The finale is set to be broadcast on its own on October 29. The season was also released on Hulu in the United States and internationally on Disney+. In Canada, Australia and the United Kingdom the episodes are set to premiere on Disney+ the day after the broadcast in the United States.
The convention had reverted to defining the atomic mass of hydrogen as 1, although at the level of precision of measurements at that time – relative uncertainties of around 1% – this was numerically equivalent to the later standard of oxygen = 16. However the chemical convenience of having oxygen as the primary atomic mass standard became ever more evident with advances in analytical chemistry and the need for ever more accurate atomic mass determinations. The name mole is an 1897 translation of the German unit Mol, coined by the chemist Wilhelm Ostwald in 1894 from the German word Molekül (molecule). The related concept of equivalent mass had been in use at least a century earlier. In chemistry, it has been known since Proust's law of definite proportions (1794) that knowledge of the mass of each of the components in a chemical system is not sufficient to define the system. Amount of substance can be described as mass divided by Proust's "definite proportions", and contains information that is missing from the measurement of mass alone. As demonstrated by Dalton's law of partial pressures (1803), a measurement of mass is not even necessary to measure the amount of substance (although in practice it is usual). There are many physical relationships between amount of substance and other physical quantities, the most notable one being the ideal gas law (where the relationship was first demonstrated in 1857). The term "mole" was first used in a textbook describing these colligative properties.
It is the sedating ingredient of NyQuil (generally in combination with dextromethorphan and acetaminophen). In Commonwealth countries, such as Australia, Canada, South Africa, and the United Kingdom, doxylamine is available prepared with paracetamol (acetaminophen) and codeine under the brand name Dolased, Propain Plus, Syndol, or Mersyndol, as treatment for tension headache and other types of pain. Doxylamine succinate is used in general over-the-counter sleep-aids branded as Somnil (South Africa), Dozile, Donormyl, Lidène (France, Russian Federation), Dormidina (Spain, Portugal), Restavit, Unisom-2, Sominar (Thailand), Sleep Aid (generic, Australia), Dorminox (Poland) and Noctiben Mea (Slovenia). In the United States: Doxylamine succinate is the active ingredient in many over-the-counter sleep aids branded under various names. Doxylamine succinate and pyridoxine (vitamin B6) are the ingredients of Diclegis, approved by the FDA in April 2013 becoming the only drug approved for morning sickness with a class A safety rating for pregnancy (no evidence of risk). In Canada: Doxylamine succinate and pyridoxine (vitamin B6) are the ingredients of Diclectin, which is used to prevent morning sickness. It is also available in combination with vitamin B6 and folic acid under the brand name Evanorm (marketed by Ion Healthcare). In India Doxylamine preparations are available typically in combination with pyridoxine and may also contain folic acid. Doxylamine usage is thus restricted for pregnant women.
11 January – A scrub fire breaks out in Kūaotunu in the Coromandel Peninsula, consuming 36 hectares (89 acres) by the following day. 12 January – Mayor of Hamilton Paula Southgate announces that she would not be running for a third term during the 2025 New Zealand local elections. 13 January: New Zealand and the United Arab Emirates sign a comprehensive economic partnership agreement, cutting tariffs on 98.5% of New Zealand exports to that country. 14 January – Deputy Police Commissioner Jevon McSkimming is suspended from duties due to a criminal investigation by the Independent Police Conduct Authority and the New Zealand Police. 16 January: Hundreds including Police Commissioner Richard Chambers attend the funeral of slain Nelson Police officer Senior Sergeant Lyn Fleming. Health New Zealand confirms a baby who died in November 2024 as the first death caused by whooping cough since a whooping cough epidemic was declared on 22 November 2024. 17 January – Minister of Māori Development Tama Potaka announces an overhaul of the Waitangi Tribunal's membership. 18 January: A pod of about 30 whales are stranded near Pākawau in Golden Bay / Mohua, prompting a response from local iwi, the Department of Conservation(DOC) and Project Jonah. A juvenile beaked whale is stranded and refloated at New Brighton, Christchurch. 19 January: Prime Minister Christopher Luxon implements a cabinet reshuffle, resulting in the replacement of Shane Reti as health minister by Simeon Brown, and the promotion of James Meager to the new position of Minister for the South Island.
Sources: en.wikipedia.org
It is a synthetic cyclic heptapeptide modelled on alpha-melanocyte-stimulating hormone. A lactam bridge links two side chains, forming a ring that stabilises the molecule against proteolysis. It belongs to the broader melanocortin peptide family.
No national medicines agency has approved melanotan-2 for clinical use. Afamelanotide, a related but distinct peptide, holds a marketing authorisation in the European Union for a rare photosensitivity disorder. Melanotan-2 itself is handled as a laboratory chemical.
Its broad activity across melanocortin receptors makes it a tool for probing pigmentation, appetite and vascular signalling. Early trials recorded skin darkening and other effects that were not the original focus of the work. Those observations generated hypotheses that later studies have examined.
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.