A practical reference on melanocortin receptor: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-06-15 and is reviewed periodically as new material appears.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic cyclic heptapeptide | Melanocortin receptor agonist |
| Molecular formula | C50H69N15O9 | Neutral form, mass near 1024.2 g/mol |
| Primary targets | MC1R, MC3R, MC4R, MC5R | Binding is non-selective across subtypes |
| Related compounds | Alpha-MSH, melanotan I, afamelanotide | Structurally or functionally related peptides |
| Common abbreviations | MT-II, MT-2 | Naming in the literature is not uniform |
Computer-based methods for predicting the binding orientation and affinity of an inhibitor for an enzyme such as molecular docking and molecular mechanics can be used to assist in the optimisation process. New inhibitors are used to obtain crystallographic structures of the enzyme in an inhibitor/enzyme complex to show how the molecule is binding to the active site, allowing changes to be made to the inhibitor to optimise binding in a process known as structure-based drug design. This test and improve cycle is repeated until a sufficiently potent inhibitor is produced.
The valley is home to a great variety of wildlife including deer, foxes, and the occasional coyote, while the river hosts salmon and catfish. The Rouge River Valley forms a part of Rouge National Urban Park, a national urban park situated along the eastern portion of Scarborough, and its neighbouring municipalities. Along the shore of Lake Ontario is the earthen escarpment formation known as the Scarborough Bluffs. The Bluffs are about 14 kilometres (8.7 mi) long, and reach heights of more than 60 metres (200 ft) in places. They are part of a much larger formation known as the Iroquois Shoreline, most of which is located somewhat further inland. The Iroquois Shoreline marks the extent of a prehistoric lake, Glacial Lake Iroquois, whose level was quite a bit higher than present-day Lake Ontario's. It shrank in size at the close of the last ice age. Erosion has been a problem along the Scarborough Bluffs. Properties located near the brink have been abandoned, and houses condemned, as the brink wears back away from the lake. Since the 1980s, large areas of beach at the base of the Bluffs have been reinforced with limestone breakwaters and construction rubble infilling.
March 19: Law facilitating donations to public or private charitable organizations, particularly those focused on increasing birth rates and protecting children and war orphans. April 23: Decree implementing the law of April 23, 1919, establishing an eight-hour workday in hotels, restaurants, cafés, and other food service establishments in the Paris region. May 9: Decree modifying the statutes of the Comédie-Française: both principal and substitute members must include at least one woman in each group. June 1: Circular regulating prostitution among women. July 25: Decree on the regulation of films; women may sit on the commission that grants film distribution visas. August 9: Competitive exams for editorial and translator-editor positions in the central administration of commerce and industry are opened to women for a provisional period of three years. August 27: Competitive exams for editorial and calculation clerk positions in the central administration of the Ministry of Labor and Social Welfare are opened to female candidates. October 24: Law protecting breastfeeding women: needy mothers breastfeeding their infants receive special allowances during the first year. October 25: Law creating and organizing chambers of agriculture in each French department; women with agricultural professions (or who had such work during the war) may vote and be elected. 1920
Sources: en.wikipedia.org
Miroslav Aleksić became mayor of Trstenik in 2012 as a member of the United Regions of Serbia (Ujedinjeni regioni Srbije, URS). The URS largely became dormant after the 2014 Serbian parliamentary election, and Aleksić left the party later in the year and became acting leader of a breakaway group initially called the People's Party of Serbia (Narodna stranka Srbije, NSS). The group was formally constituted as the People's Movement of Serbia in January 2015, and Aleksić was chosen as its leader in February. The party contested the 2016 parliamentary election as part of the Alliance for a Better Serbia list led by Boris Tadić, Čedomir Jovanović and Nenad Čanak. Aleksić received the eighth position on the electoral list and was elected when the alliance won thirteen mandates. The People's Movement of Serbia operated in a parliamentary alliance with Tadić's Social Democratic Party, which also contested the 2016 elections in the Alliance for a Better Serbia. Aleksić served as the parliamentary group's deputy leader. Both the alliance with the Social Democratic Party and Aleksić's deputy leadership of the parliamentary group continued after the party was restructured as the People's Party.
Irini Sereti is a Greek scientist and physician. She is chief of the HIV pathogenesis section at the National Institute of Allergy and Infectious Diseases. Sereti researches immune reconstitution inflammatory syndrome, idiopathic CD4 lymphocytopenia, and immune-based therapeutic strategies of HIV investigation.
Felinine, also known as (R)-2-amino-3-(4-hydroxy-2-methylbutan-2-ylthio)propanoic acid, is an amino acid found in cat urine and a precursor via microbial lyase of the putative cat pheromone and thiol called 3-mercapto-3-methylbutan-1-ol (MMB).
Sources: en.wikipedia.org
It is a synthetic cyclic heptapeptide and a non-selective melanocortin receptor agonist. Structurally it is modelled on alpha-melanocyte-stimulating hormone, a peptide that occurs naturally in the body.
Activation of MC1R increases pigment synthesis independently of ultraviolet exposure, which is the mechanism usually cited for darkening without sun exposure. Ultraviolet light still influences skin response through separate biological pathways.
Because the peptide binds several melanocortin receptor subtypes, its effects are not confined to pigmentation. This complicates interpretation of both intended and unintended outcomes reported in studies.
No. No major regulatory agency has granted a marketing authorisation for melanotan II as a medicine. Products sold under this name are generally presented as laboratory reagents and are not subject to the batch-release testing applied to approved drugs.