MC4 receptor raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2025-12-17. Anything still debated is marked as such rather than presented as settled.
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.
Semax is a synthetic seven-amino-acid peptide whose sequence extends the ACTH(4-10) fragment with a C-terminal proline-glycine-proline tripeptide. The commonly cited sequence is Met-Glu-His-Phe-Pro-Gly-Pro, giving a molecular formula near C37H51N9O10S and a molecular weight close to 813.9 g/mol. It belongs to the broader class of synthetic ACTH fragments studied for central nervous system effects rather than for adrenal steroid stimulation. In practice the material appears as a lyophilized white powder for laboratory work or as a dilute saline solution in clinical settings.
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.
Circulation time for the peptide is short because peptidases cleave it readily. The Pro-Gly-Pro tail is thought to slow breakdown compared with the bare ACTH fragment, but the gain appears modest. Absorption after intranasal dosing is limited, and only a fraction of a dose is expected to reach the central nervous system. Laboratory concentrations therefore sit well above levels achieved systemically, a gap that complicates translation from bench findings to clinical claims.
The mechanisms attributed to semax are inferred from animal and cell studies rather than traced to one confirmed target. The most frequently cited pathway involves increased expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal and cortical tissue. Some work points to engagement of melanocortin receptors, particularly MC4, which the parent ACTH fragment can activate. Effects on dopaminergic and serotonergic signalling have also been reported. No single account explains all observed results, and the relative weight of each pathway remains unsettled.
| 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 |
Development of the compound took place in the Soviet Union during the 1980s, largely through peptide research groups affiliated with the Shemyakin-Ovchinnikov Institute and Moscow State University. Investigators screened fragments of adrenocorticotropic hormone for activity on the central nervous system while attempting to separate cognitive effects from hormonal ones. The shortened sequence was selected because it retained behavioral activity in animal models without stimulating corticosteroid release. Early publications described the molecule as an ACTH(4-10) analog.
Published research on this peptide originates mainly from Russian laboratories, and the wider international literature is comparatively thin. Studies have used rodent models of stroke, hypoxia, and memory tasks, with a smaller number of human trials reported. Reported outcomes include changes in attention and memory measures, along with effects on neurotrophic factor expression in some experiments. Small sample sizes, inconsistent dosing protocols, and limited independent replication are widely noted limitations, so the strength of the clinical evidence remains an open question.
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. The first four residues correspond to the ACTH(4-10) fragment, while the terminal Pro-Gly-Pro extension was added to improve metabolic stability. Its molecular formula is C37H51N9O10S and its monoisotopic mass is approximately 813.9 Da. The compound is classified as a peptide research chemical and as a registered pharmaceutical product in Russia, but it does not hold marketing approval in the European Union or the United States. Naming conventions vary across supplier catalogs.
Semax is supplied as a lyophilized powder that appears white to off-white. It dissolves readily in water, phosphate-buffered saline, and other aqueous media, which simplifies preparation of working solutions for laboratory use. The nasal products registered in Russia are dilute aqueous solutions, typically around 0.1 percent peptide by weight. Organic solvents are rarely necessary and can complicate handling. Because the peptide is hygroscopic, weighing should be performed quickly and with minimal exposure to ambient humidity.
Solid material is normally kept at minus 20 degrees Celsius in a sealed, desiccated container. Reconstituted solutions are less stable and are usually divided into single-use aliquots before freezing. Repeated freeze-thaw cycles are avoided because they promote aggregation and loss of activity. Light exposure is minimized by using amber glassware or foil wrapping. Published stability data for this peptide are sparse, so recommended storage conditions rest mainly on general practice for short synthetic peptides rather than on dedicated study.
Lavín, José L; Kiil, Kristoffer; Resano, Ohiana; Ussery, David W; Oguiza, José A (2007). "Comparative genomic analysis of two-component regulatory proteins in Pseudomonas syringae". BMC Genomics. 8 397. doi:10.1186/1471-2164-8-397. PMC 2222644. PMID 17971244. Type strain of Pseudomonas syringae at BacDive – the Bacterial Diversity Metadatabase
Collins correctly identified a photo of Elton John, however Hasselhoff mistook a photo of Debbie Harry for Cyndi Lauper and they were eliminated in the first round with a score of 147. In April 2025, Collins attended the "24 Hour Piano-thon" at Liverpool Street Station which was in promotion of the third series of the Channel 4 music competition show The Piano. Collins played a rendition of Chopsticks on the piano, before performing I Wanna Dance with Somebody (Who Loves Me) by Whitney Houston alongside the Keynotes Choir. In March 2026, after attending the Cheltenham Festival the previous year and not winning anything, Collins returned to the event and ultimately won £20,000 throughout the day, which included £5,000 on one bet after she bet on a horse who won its race with odds of 9/1. In an interview during the ITV Racing coverage, Collins said attending the event had "ignited a fire in her" and encouraged other people, especially women to attend, describing it as "not just a man's sport" and added that she'd probably earn enough money at next year's event to "buy the Cheltenham Racecourse". In April 2026, Collins returned to I'm a Celebrity, 11 years after her original appearance, to take part in the second series of the "All Stars" spin-off I'm a Celebrity... South Africa, which was filmed in September 2025 and featured campmates from previous series.
=== Rare === Suicide through disinhibition Psychosis Incontinence Paradoxical behavioural disinhibition (most frequently in children, the elderly, and in persons with developmental disabilities) Rage Excitement Impulsivity The long-term effects of clonazepam can include depression, disinhibition, and sexual dysfunction.
Duterte signed the Paris Agreement on Climate Change in March 2017, after initially having misgivings about the deal which he says might limit the country's industrialization. The Agreement was ratified by the Senate on March 15, 2017. Duterte said that rich countries producing the most carbon emissions must pay smaller countries for damage caused by climate change.
== Books == Johann Hari (2002). God Save the Queen?. Icon Books. ISBN 978-1-84046-401-6. Johann Hari (2015). Chasing the Scream: The First and Last Days of the War on Drugs. Bloomsbury. ISBN 978-1-62040-890-2. Johann Hari (2018). Lost Connections: Uncovering the Real Causes of Depression – and the Unexpected Solutions. Bloomsbury. ISBN 978-1-63286-830-5. Johann Hari (2021). Stolen Focus: Why You Can't Pay Attention. Bloomsbury. ISBN 978-1-5266-2022-4. Johann Hari (2024). Magic Pill: The Extraordinary Benefits and Disturbing Risks of the New Weight Loss Drugs. Bloomsbury. ISBN 978-1-52667015 {{isbn}}: Check isbn value: length (help).
Sources: en.wikipedia.org
=== Category:EC 3.4 (act on peptide bonds - Peptidase) === Category:EC 3.4.11 Alanine aminopeptidase Category:EC 3.4.15 Angiotensin converting enzyme Category:EC 3.4.21 Serine protease Chymotrypsin (EC 3.4.21.1) Trypsin (EC 3.4.21.4) Thrombin (EC 3.4.21.5) Factor X (EC 3.4.21.6) Plasmin (EC 3.4.21.7) Acrosin (EC 3.4.21.10) Factor VII (EC 3.4.21.21) Factor IX (EC 3.4.21.22) Prolyl oligopeptidase (EC 3.4.21.26) Factor XI (EC 3.4.21.27) Elastase (EC 3.4.21.37) Factor XII (EC 3.4.21.38) Proteinase K (EC 3.4.21.64) Tissue plasminogen activator (EC 3.4.21.68) Protein C (EC 3.4.21.69) Category:EC 3.4.22 Separase (EC 3.4.22.49) Category:EC 3.4.23 Pepsin (EC 3.4.23.1) Rennet (EC 3.4.23.4) Renin (EC 3.4.23.15) Trypsinogen (EC 3.4.23.18) and (20/21/23/24/26) Plasmepsin (EC 3.4.23.39) Category:EC 3.4.24 Matrix metalloproteinase (EC 3.4.24.7) Category:EC 3.4.25 Metalloendopeptidase
==== Resignation rejected by Aníbal Torres ==== On 3 August 2022, Aníbal Torres announces and submits his resignation as President of the Council of Ministers to President Castillo, citing in particular the desire to resume his academic and university life. This resignation came in a context of strong disapproval, with 66% of Peruvians surveyed by Ipsos Peru wanting Torres to resign. On 5 August 2022, Pedro Castillo announced that he would reject it, preferring to carry out a cabinet reshuffle. On 24 August 2022, a few days after the announcement of the resignation of Minister José Luis Gavidia, Pedro Castillo appointed a new Minister of Defense and new appointments for the ministries of the Environment and for Women and Vulnerable Populations.
=== SIRIUS: Molecular formula identification === SIRIUS is the name of the umbrella application, but (for historic reasons) also the name for the identification of the molecular formula. Molecular formula refers to the elemental composition of the molecule. The mere mass of a molecule is not sufficient to determine the correct molecular formula. Even with very high mass accuracy, many molecular formulas can explain a mass measured in a spectrum, in particular in higher mass regions. In SIRIUS, molecular formula identification is done using isotope pattern analysis on the MS1 data as well as fragmentation tree computation on the MS2 data. The score of a molecular formula candidate is a combination of the isotope pattern score and the fragmentation tree score. To identify the molecular formula, SIRIUS is considering all possible molecular formulas for a set of elements. The elements most abundant in living beings are hydrogen (H), carbon (C), nitrogen (N), oxygen (O), and phosphor (P). This is the default set of elements in SIRIUS. Some less common elements result in very characteristic isotope pattern changes and can be automatically detected. Detectable elements are sulfur (S), chlorine (Cl), bromine (Br), boron (B) and selenium (Se). The current version of SIRIUS uses a deep neural network for auto-detection of elements from the isotope and fragmentation pattern of the query molecule. For very large molecules or in case of missing data (e.g., a missing isotope pattern), it is possible to restrict SIRIUS to molecular formulas found in a database, such as PubChem.
The Economic and Social Research Institute (ESRI) is an independent research institute in Dublin, Ireland. Its research focuses on Ireland's economic and social development to inform policy-making and societal understanding. The Institute of International and European Affairs (IIEA) focuses on European and International affairs. The Iona Institute is a conservative, Catholic think tank. TASC (Think tank for Action on Social Change) is an Irish left-wing think tank.
Sources: en.wikipedia.org
In March 1973, the Argentine government and the Union Argentina de Rugby had a great conflict: the government contested to UAR the permit given to San Isidro Club to visit South Africa, and forced the federal committee of UAR to resign. A new committee was elected on 24 April 1973. In November the government also forbade all visits to South Africa by any Argentine team and any visit of a South African team into Argentina. This ban remained until 1991. South Africa was the indirect cause of the 1976 Olympic boycott. A New Zealand rugby union tour of South Africa prompted African countries to demand that the New Zealand Olympic team be excluded from the games. The IOC demurred on the grounds that rugby union was not an Olympic sport and the New Zealand Rugby Union was not affiliated to the New Zealand Olympic Committee. Of 28 African invitees, 26 boycotted the Games, joined by Iraq and Guyana. In February 1977, Danie Craven flew to London to plead for South African rugby's reintegration into the international scene, and to make a last ditch attempt to save the Springboks' scheduled tour of the British Isles in 1978, and the British Lions tour of South Africa in 1980.
=== Political views === Psychologists in the happiness community feel politics should promote population happiness. Politics should also consider level of human happiness among future generations, concern itself with life expectancy, and focus on the reduction of suffering. Based on political affiliation, some studies argue conservatives, on average, are happier than liberals. A potential explanation is greater acceptance of income inequalities in society leads to a less worried nature. Luke Galen, Associate Professor of Psychology at Grand Valley State University, mentioned political commitments as important because they are a sort of secular world view that, like religion, can be generally beneficial to coping with death anxiety (see also Terror management theory and religion and happiness).
==== Less frequent ==== Hb H (β4) Hb Barts (γ4) Hb O (α2βO2) Hb Bassett Hb Kansas Hb D-Punjab Hb O-Arab Hb G-Philadelphia Hb Hasharon Hb Kirklareli Hb Lepore Hb M Hb Hope Hb Pisa Hb J Hb N-Baltimore Hemoglobin Chesapeake Hemoglobin Louisville Hemoglobin Vanvitelli
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.
It consists mainly of animal experiments and small clinical reports, with much of the clinical material published in Russian-language journals. Large independent trials are scarce. Separating reliable effects from chance findings is consequently difficult.