If you have been reading about MC1R 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 2025-12-09. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic cyclic heptapeptide | Analog of alpha-melanocyte-stimulating hormone |
| Primary receptor family | Melanocortin receptors MC1R through MC5R | Binding is not subtype-selective |
| Development period | 1980s | Synthesized during pigmentation and appetite research |
| Regulatory status | Not an approved medicine | No major regulator has authorized human use |
| Related compound | Afamelanotide | Linear analog studied for photoprotection |
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 with the sequence Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, corresponding to a molecular formula of C50H69N15O9 and a monoisotopic mass near 1024 daltons. It was designed as a structural analogue of alpha-melanocyte-stimulating hormone, a peptide hormone produced by cleavage of proopiomelanocortin. A lactam bridge between the aspartate and lysine side chains closes the ring, and the C-terminal amide removes a free carboxyl group. Both modifications increase resistance to enzymatic degradation compared with the linear parent hormone. Four substitutions distinguish it from afamelanotide, the linear analogue studied under the name melanotan I.
Receptor-binding studies classify melanotan II as a non-selective melanocortin agonist. It interacts with MC1R, MC3R, MC4R and MC5R, with reported affinities in the low nanomolar range and no strong subtype preference. Activation of MC1R on dermal melanocytes shifts pigment synthesis toward eumelanin, the dark polymer deposited in melanosomes and transferred to keratinocytes. Because the same peptide engages MC4R in the hypothalamus, it also appears in animal work on food intake and erectile response, which is why it is discussed in both pigment and metabolic research. Which receptor populations dominate after systemic exposure in humans is not fully established.
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.
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.
The North American Aviation P-51 Mustang is an American long-range, single-seat fighter and fighter-bomber used during World War II and the Korean War, among other conflicts. The Mustang was designed in 1940 by a team headed by James H. Kindelberger of North American Aviation (NAA) in response to a request from the British Purchasing Commission. The commission approached NAA to build Curtiss P-40 fighters under license for the Royal Air Force (RAF). Rather than build an old design from another company, NAA proposed the design and production of a more modern fighter. The prototype NA-73X airframe was completed on 9 September 1940, 102 days after contract signing, achieving its first flight on 26 October. The Mustang was designed to use the Allison V-1710 engine without an export-sensitive turbocharger or a multi-stage supercharger, resulting in limited high-altitude performance. The aircraft was first flown operationally by the RAF as a tactical-reconnaissance aircraft and fighter-bomber (Mustang Mk I). In mid 1942, a development project known as the Rolls-Royce Mustang X, replaced the Allison engine with a Rolls-Royce Merlin 65 two-stage inter-cooled supercharged engine. During testing at Rolls-Royce's airfield at Hucknall in England, it was clear the engine dramatically improved the aircraft's performance at altitudes above 15,000 ft (4,600 m) without sacrificing range.
=== Other uses === Rhodium is used as an alloying agent for hardening and improving the corrosion resistance of platinum and palladium. These alloys are used in furnace windings, bushings for glass fiber production, thermocouple elements, electrodes for aircraft spark plugs, and laboratory crucibles. Other uses include electrical contacts, where it is valued for small electrical resistance, small and stable contact resistance, and great corrosion resistance, and filters and anodes in mammography systems that emit a lower radiation dose than comparable systems using molybdenum. Rhodium plated by either electroplating or evaporation is extremely hard and useful for optical instruments. In automobile manufacturing, rhodium is also used in the construction of headlight reflectors. Rhodium neutron detectors are used in nuclear reactors to measure neutron flux levels—this method requires a digital filter to determine the current neutron flux level, generating three separate signals: immediate, a few seconds delay, and a minute delay, each with its own signal level; all three are combined in the rhodium detector signal. The three Palo Verde nuclear reactors each have 305 rhodium neutron detectors, 61 detectors on each of five vertical levels, providing an accurate 3D "picture" of reactivity and allowing fine tuning to consume the nuclear fuel most economically.
A ruddy (red) complexion, or plethora Headache, transient blurry vision (amaurosis fugax), other signs of a transient ischemic attack (TIA) or stroke Dizziness, fatigue Unusual bleeding, nosebleeds Pain in abdomen from enlarged spleen in polycythemia vera Pain in hands and feet (erythromelalgia) Itchiness, especially after a hot shower (aquagenic pruritis) Numbness or tingling in different body parts
DHPLC is easily automated as no labeling or purification of the DNA fragments is needed. The method is also relatively fast and has a high specificity. One major drawback of DHPLC is that the column temperature must be optimized for each target in order to achieve the right degree of denaturation.
== Pharmacology == GABOB is a GABA receptor agonist. It has two stereoisomers, and shows stereoselectivity in its actions. Specifically, (R)-(–)-GABOB is a moderate-potency agonist of the GABAB receptor, while (S)-(+)-GABOB is a partial agonist of the GABAB receptor and an agonist of the GABAA receptor. (S)-(+)-GABOB is around twice as potent an anticonvulsant as (R)-(–)-GABOB. GABOB is used medically as a racemic mixture. Relative to GABA, GABOB has more potent inhibitory effects on the central nervous system, perhaps due to its greater capacity to cross the blood–brain barrier. However, GABOB is of relatively low potency as an anticonvulsant when used by itself, and is more useful as an adjuvant treatment used alongside another anticonvulsant.
Sources: en.wikipedia.org
Ceremonial San Pedro use seems to be characterized by relatively strong spiritual experiences, and low incidence of challenging experiences. DMT (N,N-dimethyltryptamine) is an indole alkaloid found in various species of plants. Traditionally, it is consumed by tribes in South America in the form of ayahuasca. A brew is used that consists of DMT-containing plants as well as plants containing monoamine oxidase inhibitors (MAOIs), like harmine and harmaline, which allows DMT to be consumed orally without being rendered inactive by monoamine oxidase (MAO) enzymes in the digestive system. A pharmaceutical version of ayahuasca is called pharmahuasca. In the Western world, DMT is more commonly consumed via the vaporisation of freebase DMT. Whereas ayahuasca typically lasts for several hours, inhalation has an onset measured in seconds and has effects measured in minutes, being much more intense. Particularly in smoked or vaporised form, DMT has the ability to cause users to enter a hallucinatory realm fully detached from reality, being typically characterised by hyperbolic geometry, and described as defying visual or verbal description. Users have also reported encountering and communicating with entities within this hallucinatory state. DMT is the archetypal substituted tryptamine, being the structural scaffold of psilocybin and, to a lesser extent, the lysergamides. 5-MeO-DMT (5-methoxy-N,N-dimethyltryptamine; mebufotenin) is a naturally occurring substituted 5-methoxytryptamine which was first identified as having psychedelic effects in the 1960s.
=== Self-healing materials === For materials such as components in microelectronics, polymeric coatings, and adhesives, nanocapsules can reduce damage caused by high loads. The healing of cracks within these materials is alleviated by dispersing nanocapsules within the polymer. The healing substances include dicyclopentadiene (DCPD), which is prepared on site within the material by sonication. The nanoencapsulated material is first emulsified within the host material by creating an oil-in-water self-healing epoxy. The emulsified material is then agitated within the host material to form particles which then bond to the host material.
=== Perioperative === Perioperative hyperglycemia has been associated with immunosuppression, increased infections, osmotic diuresis, delayed wound healing, delayed gastric emptying, sympatho-adrenergic stimulation, and increased mortality. In addition, it reduces skin graft success, exacerbates brain, spinal cord, and renal damage by ischemia, worsens neurologic outcomes in traumatic head injuries, and is associated with postoperative cognitive dysfunction following CABG.
==== Yeasts ==== Actin's cytoskeleton is key to the processes of endocytosis, cytokinesis, determination of cell polarity and morphogenesis in yeasts. In addition to relying on actin, these processes involve 20 or 30 associated proteins, which all have a high degree of evolutionary conservation, along with many signalling molecules. Together these elements allow a spatially and temporally modulated assembly that defines a cell's response to both internal and external stimuli. Yeasts contain three main elements that are associated with actin: patches, cables, and rings. Despite not being present for long, these structures are subject to a dynamic equilibrium due to continual polymerization and depolymerization. They possess a number of accessory proteins including ADF/cofilin, which has a molecular weight of 16kDa and is coded for by a single gene, called COF1; Aip1, a cofilin cofactor that promotes the disassembly of microfilaments; Srv2/CAP, a process regulator related to adenylate cyclase proteins; a profilin with a molecular weight of approximately 14 kDa that is related/associated with actin monomers; and twinfilin, a 40 kDa protein involved in the organization of patches.
Sources: en.wikipedia.org
My grandfather came to this country circa 1895 from Montella, Italy. Around 1910, he started his grocery store, called Dominic Conti's Grocery Store, on Mill Street in Paterson, New Jersey where he was selling the traditional Italian sandwiches. His sandwiches were made from a recipe he brought with him from Italy, which consisted of a long crust roll, filled with cold cuts, topped with lettuce, tomatoes, peppers, onions, oil, vinegar, Italian herbs and spices, salt, and pepper. The sandwich started with a layer of cheese and ended with a layer of cheese (this was so the bread wouldn't get soggy).
Before the ghetto riot of 1967, Detroit's black population had the highest rate of home-ownership of any black urban population in the country, and their unemployment rate was just 3.4 percent. It was not despairing that fueled the riot. It was the riot which marked the beginning of the decline of Detroit to its current state of despair. Detroit's population today is only half of what it once was, and its most productive people have been the ones who fled. However, Thomas Sugrue argues that over 20% of Detroit's adult black population was out of work in the 1950s and 1960s, along with 30% of black youth between eighteen and twenty-four. Economist Edward L. Glaeser believes the riots were a symptom of the city's already downward trajectory:
===== The maxillary division innervation ===== Maxillary nerve – conveys sensation to the upper jaw and the face. Infraorbital nerve – conveys sensation to the area from below the eye socket to the external nares (nostrils). Zygomatic nerve – through the zygomatic bone and the zygomatic arch, conveys sensation to the cheekbone areas. Superior posterior dental nerve – sensation in the teeth and the gums. Superior anterior dental nerve – mediates the sneeze reflex. Sphenopalatine nerve – divides into the lateral branch and the septal branch, and conveys sensation from the rear and the central regions of the nasal cavity.
Sources: en.wikipedia.org
No regulator in a major market has approved it for human use. It appears in research settings and in products marketed outside pharmacy channels. Legal status for personal possession varies by country.
Afamelanotide is a linear analog that has received approval in some jurisdictions for a specific photoprotection indication. Melanotan II is cyclic and less selective across melanocortin receptors. The two are related but are not interchangeable in regulatory or clinical terms.
A compound that activates several receptor subtypes may produce effects beyond pigmentation. Selectivity influences which tissues respond and shapes the side-effect profile described in reports. Designing subtype-selective analogs is a stated goal of melanocortin research.
No. Melanotan-2 is manufactured synthetically. The naturally occurring peptide in the same family is alpha-melanocyte-stimulating hormone, which the body produces as part of normal endocrine and neural signalling.