The short version of melanocortin receptor fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-03-07 and is reviewed periodically as new material appears.
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.
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.
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.
| 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 |
An umbrella review and a continuing education article differ as to whether it is effective in the treatment of AD. Atypical antipsychotics are modestly useful in reducing aggression and psychosis in people with AD, but their advantages are offset by serious adverse effects, such as stroke, movement difficulties, or cognitive decline. They are recommended in dementia only after first-line therapies such as behavior modification have failed, and due to the risk of adverse effects, they should be used for the shortest amount of time possible. Stopping antipsychotic use in this group of people appears to be safe.
== Signs and symptoms == Sydenham's chorea is characterized by the abrupt onset (sometimes within a few hours) of neurological symptoms, classically chorea, which are non-rhythmic, writhing or explosive involuntary movements. Usually all four limbs are affected, but there are cases reported where just one side of the body is affected (hemichorea). Typical chorea includes repeated wrist hyperextension, grimacing, and lip pouting. The fingers can move as if playing the piano. There may be tongue fasciculations ("bag of worms") and motor impersistence, for example, the "milkmaid sign" (grip strength fluctuates, as if hand milking a cow), or inability to sustain tongue protrusion (called jack-in-the-box tongue or serpentine tongue, as the tongue slides in and out of the mouth), or eye closure. There is usually a loss of fine motor control, which is particularly obvious in handwriting if the child is of school age. Speech is often affected (dysarthria), as is walking; legs will suddenly give way or flick out to one side, giving an irregular gait and the appearance of skipping or dancing. Underlying the abnormal movements is often low tone (hypotonia) which may not become obvious until treatment is started to suppress the chorea. The severity of the condition can vary from just some instability on walking and difficulty with handwriting, to the extreme of being wholly unable to walk, talk, or eat (chorea paralytica). Movements cease during sleep.
=== Western culture === The scorpion with its powerful sting has been used as the name or symbol of various products and brands, including Italy's Abarth racing cars. In the Roman army, the scorpio was a torsion siege engine used to shoot a projectile. The British Army's FV101 Scorpion was an armoured reconnaissance vehicle or light tank in service from 1972 to 1994. It holds the Guinness world record for the fastest production tank. A version of the Matilda II tank, fitted with a flail to clear mines, was named the Matilda Scorpion. Several ships of the Royal Navy have been named HMS Scorpion, including an 18-gun sloop in 1803, a turret ship in 1863, and a destroyer in 1910. A hand- or forearm-balancing asana in modern yoga as exercise with the back arched and one or both legs pointing forwards over the head is called Scorpion pose, a pose of yoga which was originated in ancient India and influential practice in classical Hinduism which is currently becoming popular in the West. A variety of martial arts films and video games have been entitled Scorpion King. A Montesa scrambler motorcycle was named Scorpion. Scorpions have equally appeared in western artforms including film and poetry: the surrealist filmmaker Luis Buñuel made symbolic use of scorpions in his 1930 classic L'Age d'or (The Golden Age), while Stevie Smith's last collection of poems was entitled Scorpion and other Poems.
== Further reading == Spiegelhalter, David J.; Abrams, Keith R.; Myles, Jonathan P. (2004). "Randomised Controlled Trials". Bayesian Approaches to Clinical Trials and Health-Care Evaluation. Chichester: John Wiley & Sons. pp. 181–249. ISBN 0-471-49975-7. Chin, Jane Y. (1 August 2004). "The Clinical Side: Clinical trial endpoints". Pharmaceutical Representative. Archived from the original on 5 October 2011.
== Use as feed == Biuret is used as a non-protein nitrogen source in ruminant feed, where it is converted into protein by gut microorganisms. It is less favored than urea, due to its higher cost and lower digestibility but the latter characteristic also slows down its digestion and so decreases the risk of ammonia toxicity.
Sources: en.wikipedia.org
== Terminology and classification == "Coeliac disease" is the preferred spelling in Commonwealth English, whereas "celiac disease" is typically used in North American English. The terms sprue, coeliac sprue, gluten-sensitive enteropathy, non-tropical sprue and idiopathic steatorrhoea have been used as synonyms for coeliac disease in the past. Both gluten intolerance and gluten sensitivity have been used as synonyms of coeliac disease or to describe other symptoms triggered by gluten. The terms are nonspecific and lack a consistent definition. Gluten-related disorders are conditions related to gluten such as coeliac disease, gluten ataxia, wheat allergy, dermatitis herpetiformis, and non-coeliac gluten sensitivity. Many individuals with coeliac disease are asymptomatic, meaning they do not have any symptoms associated with coeliac disease. Those with asymptomatic coeliac disease are commonly diagnosed through screening programs. The term "silent coeliac disease" is equivalent to asymptomatic, but usage is discouraged. Coeliac disease can be symptomatic (previously called overt coeliac disease) or subclinical. Subclinical coeliac disease has historically had many different definitions, such as those with symptoms mainly outside the gastrointestinal tract, or those with clinical signs of the disease (anaemia, laboratory abnormalities, and endoscopic features) but no symptoms. Subclinical coeliac disease is now used when individuals who do not have symptoms that commonly warrant testing for coeliac disease have positive serology for coeliac disease.
=== Secretome alters with exercise === A study examined the biopsies of a thigh skeletal muscle (vastus lateralis muscle) of eight 23-year old, originally sedentary, Caucasian males. Biopsies were taken both before and after a six-week long endurance exercise training program. The exercise consisted of riding a stationary bicycle for one hour, five days a week for six weeks. Of the 13,108 genes with detected expression in the muscle biopsies, 641 genes were upregulated after endurance training and 176 genes were downregulated. Of the 817 total altered genes, 531 were identified as being in the secretome by either or both of UniProt or ExoCarta, or else by studies investigating the secretome of muscle cells. Because many of the exercise-regulated genes are identified as secreted, this indicates that much of the effect of exercise has an endocrine rather than metabolic function. The main pathways found to be affected by secreted exercise-regulated proteins were related to cardiac, cognitive, kidney and platelet functions.
The longest-lived isotope of einsteinium, 252Es (half-life 471.7 days) would be more suitable for investigation of physical properties, but it has proven far more difficult to produce and is available only in minute quantities, not in bulk. Einsteinium is the element with the highest atomic number which has been observed in macroscopic quantities in its pure form as einsteinium-253. Like all synthetic transuranium elements, isotopes of einsteinium are very radioactive and are considered highly dangerous to health on ingestion.
On the other hand, however, the generic masculine in German often allows for nuances that would not be possible in other languages, according to Kermani: “For example, when I send an email to my friends to invite them to my birthday party, I purposely do not address them as ‘male and female friends’ (‘Freundinnen und Freunde’).” As Kermani states, the use of the generic masculine is frequently understood as a provocation—that is, as the opposite of what it actually achieves: a renunciation of sexualization. At the same time, Kermani notes, for reasons of politeness and in public situations where the generic masculine might be perceived as an affront, hehimself will opt for a form of address that includes both male and female genders. If the presence of a masculine grammatical form came to indicate that it no longer ignored gender identity but, on the contrary, that it overemphasized gender identity, the generic masculine would be dead for good. - Navid Kermani: Mann, Frau, völlig egal [Man, Woman, It Doesn’t Matter at All]
Sources: en.wikipedia.org
Commercial motor vehicles such as cars, vans, trucks, specialist vehicles (such as mobile construction machinery), forklifts, and trailers Private vehicles used for work purposes (the 'grey fleet') Aviation machinery such as aircraft (planes and helicopters) Ships Rail cars Non-powered assets such as generators, tanks, gear boxes, dumpsters, shipping containers, trailers, excavators, and other equipment that can't run on its own power. Fleet (vehicle) management can include a range of functions, such as vehicle leasing and financing, vehicle maintenance, licensing and compliance, supply chain management, accident management and subrogation, vehicle telematics (tracking and diagnostics), driver management, speed management, fuel management, health and safety management, and vehicle re-marketing. Fleet Management is a function which allows companies which rely on transportation in business to remove or minimize the risks associated with vehicle investment, improving efficiency, productivity and reducing their overall transportation and staff costs, providing 100% compliance with government legislation (duty of care) and many more. These functions can be dealt with by either an in-house fleet-management department or an outsourced fleet-management provider. The number of light duty vehicles registered in commercial fleets in Europe as of 2016 was 15 million, and 19.5 million in North America. Even with these record numbers of registration, light duty vehicles represent only 62% of all fleet sales.
Major royal jelly proteins (MRJPs) are a family of proteins secreted by honey bees. The family consists of nine proteins, of which MRJP1 (also called royalactin), MRJP2, MRJP3, MRJP4, and MRJP5 are present in the royal jelly secreted by worker bees. MRJP1 is the most abundant, and largest in size. The five proteins constitute 83–90% of the total proteins in royal jelly. They are synthesised by a family of nine genes (mrjp genes), which are in turn members of the yellow family of genes such as in the fruitfly (Drosophila) and bacteria. They are involved in differential development of queen larvae and worker larvae, thus establishing division of labour in the bee colony.
Here, Mr(X) is the relative molar mass, also called molecular weight or formula weight. For normal samples from Earth with typical isotope composition, the standard atomic weight or the conventional atomic weight can be used as an approximation of the relative atomic mass of the sample. Examples are:
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.
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.