If you have been reading about Melanocortin receptor 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.
Updated 2026-02-27. Numbers and descriptions here follow the published literature rather than marketing material.
Development is attributed to researchers at the Institute of Molecular Genetics in Moscow during the early 1980s, building on earlier Soviet work with ACTH fragments. Russian regulatory approval followed for intranasal use, and the compound has remained commercially available there for decades. Most published human data originate from Russian and, later, some Eastern European clinical reports, which are not always accessible in English translation. Outside that region the material is generally handled as a research chemical rather than a licensed medicine.
Regulatory status differs sharply between jurisdictions. In Russia the peptide is registered as a prescription nasal preparation, while agencies such as the United States Food and Drug Administration have not approved it for any indication. Products sold elsewhere are typically labeled for laboratory research only, and such labels shift responsibility for safe handling to the purchaser. Because the same name covers pharmaceutical-grade nasal drops and bulk research powder, identity and purity documentation becomes the main practical concern when comparing sources.
Laboratory work points toward modulation of neurotrophic signaling, particularly expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal tissue. Studies also describe effects on monoamine turnover, inflammatory mediators, and oxidative markers. These observations come mainly from animal models and cultured cells, so the causal chain in humans is not firmly established. Whether the reported molecular changes translate into measurable clinical benefit is an open question. Reviews generally present the mechanism as plausible rather than demonstrated.
Clinical evidence consists largely of small trials with modest sample sizes, often without independent replication. Reported endpoints include cognitive scores, recovery after stroke, and visual function, but study designs vary widely and few trials meet contemporary reporting standards. Systematic reviewers have noted a high risk of bias in several of these reports. No large multicenter trial conducted outside Russia has been published. The compound is therefore best described as investigational in most jurisdictions, with its clinical role still unresolved.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide (ACTH fragment analog) | Not a steroid; does not belong to the melanocortin agonist drugs by marketing category |
| Molecular formula | C37H51N9O10S (commonly cited) | Reported values vary slightly with salt and counter-ion content |
| Appearance | White to off-white lyophilized powder | A single batch may appear as a loose cake or fluffy solid |
| Solubility | Freely soluble in water and aqueous buffer | Stock solutions are usually prepared in sterile water or saline |
| Typical storage | −20 °C or below, desiccated and protected from light | Seal opened vials promptly to limit moisture uptake |
Russian regulatory authorities approved the peptide for nasal administration, and it remains listed in the national pharmacopoeia under several trade names. Documented indications include acute ischemic stroke, transient ischemic attacks, traumatic brain injury, and certain ophthalmological and neurological conditions. Physicians also prescribe it for cognitive complaints in older patients, although the evidence base for that use is thinner. Outside Russia and a few neighboring states, the substance is not an approved medicine and is sold instead as a research chemical.
Later generations of the molecule include an N-acetylated form and an amidated form, both marketed online alongside the parent peptide. These variants differ in terminal chemistry and stability, and they are frequently discussed in the same breath even though they have not been compared in controlled trials. Supply outside formal healthcare systems comes largely from laboratories that synthesize peptides to order. Purity and identity of these materials vary widely, and no single body oversees the international trade.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It was derived from the ACTH(4-10) fragment, a short segment of adrenocorticotropic hormone that lacks the hormonal activity associated with the full-length peptide. Researchers at the Institute of Molecular Genetics in Moscow developed the compound during the 1980s. It has been registered as a pharmaceutical product in Russia and several neighbouring countries, where it is supplied as a nasal solution, and it is also sold internationally as a research chemical.
The proposed mechanism centres on neurotrophic signalling rather than direct receptor activation. Semax is reported to increase expression of brain-derived neurotrophic factor and nerve growth factor in several brain regions, and to shift the balance between excitatory and inhibitory neurotransmitter systems. Interaction with melanocortin receptors has been suggested because of the parent ACTH fragment. Many of these findings come from rodent studies, and the extent to which they translate to human physiology remains an open question.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its design combines the ACTH(4-7) core fragment with a C-terminal Pro-Gly-Pro extension, a modification intended to improve stability and prolong activity. The molecule is hydrophilic, carries no lipid chains or glycosylation, and has a theoretical mass just over 810 daltons in its free form. All seven residues are proteinogenic amino acids, so no non-natural building blocks appear in the backbone. A free N-terminal methionine and C-terminal proline define the unmodified parent peptide.
The compound was developed during the 1980s at the Institute of Molecular Genetics in Moscow as part of research on fragments of adrenocorticotropic hormone. Early work examined short ACTH-derived sequences that retained neurotrophic effects while lacking the endocrine activity of the full hormone. Semax entered clinical use in Russia during the 1990s, where it received registration for several neurological indications. Outside that region it remained primarily a laboratory research material rather than an approved therapeutic. English-language literature on it grew more slowly and frequently cited the original Russian studies.
Terminology around the compound varies by source. It appears in catalogues and papers as Semax, as the heptapeptide ACTH(4-7)-Pro-Gly-Pro, and under various alphanumeric laboratory codes used by individual suppliers. These names refer to the same sequence but may imply different salt forms, purity grades, or counter-ions. Peptide databases usually list the free base mass, while product descriptions sometimes report acetate or trifluoroacetate salts with a different formula weight. Because naming conventions for research peptides are not standardised across vendors, checking the declared sequence and measured mass is more reliable than relying on a trade name alone.
=== Management === Heat-shock proteins also occur under non-stressful conditions, simply "monitoring" the cell's proteins. Some examples of their role as "monitors" are that they carry old proteins to the cell's "recycling bin" (proteasome) and they help newly synthesised proteins fold properly. These activities are part of a cell's own repair system, called the "cellular stress response" or the "heat-shock response". Recently, there are several studies that suggest a correlation between HSPs and dual frequency ultrasound as demonstrated by the use of LDM-MED machine. Heat shock proteins appear to be more susceptible to self-degradation than other proteins due to slow proteolytic action on themselves.
==== Amyotrophic lateral sclerosis ==== It has been shown that amyotrophic lateral sclerosis (ALS) is clearly linked to changes in glutamate signaling and glutathione levels; there is also an astrocytic component linked to the disease. All of these factors suggest that a dysfunction in system Xc- may contribute to ALS. It has been observed that an increase in the expression of Nrf2, a transcription factor for system Xc-, leads to a protective effect in mice with ALS symptoms.
=== Honours === House of Habsburg: Grand Mistress Dame of the Order of the Starry Cross Dame Grand Cross of the Order of Elisabeth, 1913 Knight Grand Officer of the Order of the Red Cross, with War Decoration Sovereign Military Order of Malta: Dame Grand Cross of Honour and Devotion of the Order of Saint John
=== Cinematography === Ricoh GR digital cameras, a series of digital cameras manufactured by Ricoh Ricoh GR (large sensor compact camera), the current line of cameras in the GR series Golmaal Returns, a Hindi comedy film Generator Rex, an animated sci-fi series Guilty Remnant, a fictional cult in The Leftovers (TV series)
Pauling–Corey–Branson α-helix (from the names of three scientists who described its structure) 3.613-helix because there are 3.6 amino acids in one ring, with 13 atoms being involved in the ring formed by the hydrogen bond (starting with amidic hydrogen and ending with carbonyl oxygen)
Sources: en.wikipedia.org
== Interactions == Pappalysin-1 has been shown to interact with major basic protein. Studies conducted at the Royal London Hospital in the United Kingdom, have shown that a marker of Down syndrome may be expressed during the first trimester and second trimester of a pregnancy term. Concentrations of the Pregnancy-Associated Plasma Protein (PAPPA) gene as well as other markers can help screen for Down syndrome in the beginning stages of a woman's gestational period.
The metabolism of propionyl-CoA occurs in the mitochondria and requires Vitamin B12 (as adenosylcobalamin) to make succinyl-CoA. When the conversion of propionyl-CoA to succinyl-CoA in the mitochondria fails due to Vitamin B12 deficiency, elevated blood levels of methylmalonic acid (MMA) occur. Thus, elevated blood levels of homocysteine and MMA may both be indicators of vitamin B12 deficiency. Adenosylcobalamin is needed as cofactor in methylmalonyl-CoA mutase—MUT enzyme. Processing of cholesterol and protein gives propionyl-CoA that is converted to methylmalonyl-CoA, which is used by MUT enzyme to make succinyl-CoA. Vitamin B12 is needed to prevent anemia, since making porphyrin and heme in mitochondria for producing hemoglobin in red blood cells depends on succinyl-CoA made by vitamin B12.
Rotaxane-based molecular machines have been of initial interest for their potential use in molecular electronics as logic molecular switching elements and as molecular shuttles. These molecular machines are usually based on the movement of the macrocycle on the dumbbell. The macrocycle can rotate around the axis of the dumbbell like a wheel and axle or it can slide along its axis from one site to another. Controlling the position of the macrocycle allows the rotaxane to function as a molecular switch, with each possible location of the macrocycle corresponding to a different state. These rotaxane machines can be manipulated both by chemical and photochemical inputs. Rotaxane based systems have also been shown to function as molecular muscles. In 2009, there was a report of a "domino effect" from one extremity to the other in a Glycorotaxane Molecular Machine. In this case, the 4C1 or 1C4 chair-like conformation of the mannopyranoside stopper can be controlled, depending on the localization of the macrocycle. In 2012, unique pseudo-macrocycles consisting of double-lasso molecular machines (also called rotamacrocycles) were reported in Chem. Sci. These structures can be tightened or loosened depending on pH. A controllable jump rope movement was also observed in these new molecular machines.
=== University of Oxford === Despite his success in revitalising the pathology department at Sheffield, Florey had grander ambitions than following the example of Douglas and dying in office. An opportunity arose with the death of Georges Dreyer on 17 August 1934, the holder of the chair of pathology in the Sir William Dunn School of Pathology at Oxford. Dreyer had overseen the construction of a palatial new laboratory, but by 1934 it had attracted few students and researchers. While Florey had reservations about leaving Sheffield for Guy's, he had none about Oxford. The electoral board met on 22 January 1935, and Florey was appointed Professor of Pathology and Fellow of Lincoln College, Oxford, which controlled the chair, effective 1 May 1935. The chair came with an annual salary of £1,700 (equivalent to £105,000 in 2025). The school's budget was £3,432 a year (equivalent to £211,000 in 2025) for all equipment and salaries except Florey's. He enforced strict economy measures such as forbidding the use of the lift, which saved £25 a year.
Sources: en.wikipedia.org
=== Principles === During its life, a plant or animal is in equilibrium with its surroundings by exchanging carbon either with the atmosphere or through its diet. It will, therefore, have the same proportion of 14C as the atmosphere, or in the case of marine animals or plants, with the ocean. Once it dies, it ceases to acquire 14C, but the 14C within its biological material at that time will continue to decay, and so the ratio of 14C to 12C in its remains will gradually decrease. Because 14C decays at a known rate, the proportion of radiocarbon can be used to determine how long it has been since a given sample stopped exchanging carbon – the older the sample, the less 14C will be left. The equation governing the decay of a radioactive isotope is:
Short-acting insulin analogues are modified forms of recombinant human insulin designed to enhance subcutaneous absorption and accelerate glycemic control. In standard insulin formulations, regular insulin monomers naturally aggregate into hexamers, a configuration that delays absorption and prolongs the onset of action. Before entering the bloodstream, these hexamers must dissociate into dimers and then monomers, which slows their availability for glucose regulation. To address this limitation, insulin analogues have been engineered to maintain a monomeric or dimeric configuration, allowing for faster absorption and reducing the time to onset to approximately 5 to 15 minutes. Insulin lispro, insulin aspart, and insulin glulisine are the most widely used short-acting insulin analogues. These formulations are structurally identical to human insulin, except for amino acid substitutions at one or two positions, which modify their stability and absorption characteristics. Insulin lispro, which was first approved in 1996 and marketed as Humalog among others, works by reversing the final lysine and proline residues on the C-terminal end of the B-chain. This modification does not alter receptor binding, but blocks the formation of insulin dimers and hexamers. Clinical studies have demonstrated that the use of insulin lispro instead of regular insulin can reduce hypoglycemia incidence and improve glycemic control.
Bryza said that by the night of 7 August, he had called on the Georgian officials not to open fire on the invading Russians. Evgeny Gontmakher, member of the board of the Institute of Contemporary Development, said that he was told by employees of the Russian government that the major resolutions during the war were not made without Putin. Brigadier general Kārlis Krēsliņš said in an interview that Russian assertion that the war began on the night of 7 to 8 August was not true because six Georgian policemen were targeted by mine on 1 August and a Georgian village was bombarded on 2 August from the Ossetian-inhabited territory controlled by the Russian peacekeepers. Krēsliņš said that the Georgian servicemen noticed in 2008 that Ossetians continued to shoot whether did the Georgian troops return fire or not. Krēsliņš commented on the Russian readiness, "The [Russian] military was expecting only an order, and politicians organized the reason for such an order to be given." Krēsliņš said that Georgia noticed how the Russian troops were amassing on the border, but Georgia did not believe that Russia would attack, although Georgia was expecting that a Russian attack would probably begin in Abkhazia. He stated that Georgia was not prepared for the Russian invasion. Krēsliņš opined that Georgia could successfully defend against the Russian invasion due to its mountains, however, according to his information, Georgia ruled out this because Russia threatened to destroy the country's capital from the air. On 18 September 2008, the U.S.
Sources: en.wikipedia.org
It is a short synthetic peptide built from seven amino acids: methionine, glutamic acid, histidine, phenylalanine and three prolines. The sequence derives from the 4-10 fragment of adrenocorticotropic hormone with an added proline-glycine-proline tail. No plant or animal extract is involved; the material is produced by solid-phase peptide synthesis.
It was developed in the Soviet Union during the early 1980s by groups at the Institute of Molecular Genetics in Moscow. Russian approval for intranasal use followed, and it has been marketed there since. Western laboratories encountered it mainly through translated literature and, later, through online research-chemical trade.
It holds a Russian registration as a prescription nasal product but has no approval from the European Medicines Agency or the United States Food and Drug Administration. Buyers outside Russia usually receive material sold strictly for laboratory research. That distinction matters because research-grade and pharmaceutical-grade products carry different documentation and testing expectations.
Semax is a synthetic seven-amino-acid peptide derived from a fragment of corticotropin. It is used in Russia as a nasal preparation, while elsewhere it is studied as a research compound. It is not approved as a medicine in most countries.