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Chemical Identity And Research Background — Background and Details

By Editorial Desk · published 2026-04-13 · last reviewed 2026-05-20 · Topic

This is a working overview of Melanocortin receptor, written for readers who want more than a one-paragraph summary but less than a textbook.

Reviewed 2026-05-20. Anything still debated is marked as such rather than presented as settled.

Chemical Identity and Research Background

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.

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.

Mechanism and Research

Published studies are dominated by animal models of stroke, ischemia, and cognitive impairment, with a smaller number of human trials conducted in Russia. Many of the human reports are small, single-center, and published in Russian-language journals, which limits independent scrutiny. Outcome measures vary between studies and often rely on clinician-rated scales rather than objective biomarkers. Systematic reviews have noted the methodological weaknesses and called for larger, preregistered trials before firm conclusions can be drawn.

Claims about enhanced focus, memory, or mood in healthy people rest mostly on anecdotal reports and community discussion rather than on controlled data. It remains unclear whether any cognitive benefit observed in patients recovering from brain injury would extend to uninjured users. Dose-response relationships, long-term safety, and interactions with other drugs are not well characterized in the peer-reviewed literature. Questions about optimal route of administration and treatment duration likewise remain open.

Semax binds to melanocortin receptors and is thought to influence neuronal survival and plasticity rather than to act through the adrenal axis. Laboratory work has shown increased expression of brain-derived neurotrophic factor and nerve growth factor in treated tissue. Changes in c-Fos, a marker of neuronal activation, have also been reported. Because the peptide is rapidly degraded by peptidases, its effects are generally attributed to downstream signaling cascades rather than to sustained receptor occupancy.

Semax at a glance

PropertyValueNotes
Molecular formulaC37H51N9O10SSeven-residue peptide
Molecular mass813.9 DaMonoisotopic value
AppearanceWhite to off-white powderLyophilized form
SolubilityFreely soluble in waterAlso soluble in saline and polar solvents
Storage (dry)-20 °C or lowerDesiccated, protected from light

Semax Peptide Structure and Origin

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.

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.

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Handling, Stability, and Analytical Control

Dissolution is normally performed in water, phosphate-buffered saline, or normal saline, since the peptide is freely soluble in aqueous media and is rarely handled with strong organic solvents. Solution pH should be kept near neutral, because extreme acidity or alkalinity accelerates backbone hydrolysis and encourages oxidation of the methionine side chain. Once dissolved, the material is less stable than the dry powder and is commonly divided into single-use portions and frozen. Buffers containing primary amines, such as Tris, are often avoided because of possible side reactions.

Purity assessment relies mainly on reversed-phase high-performance liquid chromatography, which separates the target heptapeptide from truncated sequences, deletion analogues, and oxidised forms. Mass spectrometry, usually coupled to liquid chromatography, confirms identity through the expected molecular ion and reveals modifications such as methionine sulfoxide formation. Amino acid analysis can verify composition, and tandem mass spectrometry supports sequence confirmation. Ultraviolet detection near 254 to 280 nanometres is convenient because the phenylalanine and histidine residues absorb in that region. Nuclear magnetic resonance is rarely used for routine release testing.

Supporting material

7 July Starmer makes his first visit to Scotland as prime minister, for a meeting with First Minister John Swinney. Lewis Hamilton of Mercedes takes his ninth victory at the British Grand Prix, breaking the record for the most wins at a single circuit and Grand Prix, and the most wins at a driver's home Grand Prix, bringing an end to a 56 winless race streak and making him the first driver to win a race after their 300th Grand Prix start. 8 July The Chancellor, Rachel Reeves, announces new housebuilding targets for England, and the loosening of planning rules to encourage more new homes. The ban on onshore wind in England is lifted. 9 July Minister Jim McMahon tells BBC News that the phrase "levelling-up" will be replaced with "local government" and that his department will now be named the Ministry of Housing, Communities and Local Government. Health Secretary Wes Streeting begins talks aimed at ending a long-running pay dispute with junior doctors in England. Starmer holds his second cabinet meeting, after telling England's regional mayors he will meet with them regularly to help growth across the UK. The first meeting of the 59th Parliament of the United Kingdom takes place. Vacuum manufacturer Dyson announces it is cutting a third of its UK workforce as part of a global restructuring strategy. 10 July Starmer travels to Washington, D.C., his first foreign trip as UK Prime Minister, to attend the 75th NATO summit.

=== Gene therapy prior to conception === Mitochondrial replacement therapy (MRT), where the nuclear DNA is transferred to another healthy egg cell leaving the defective mitochondrial DNA behind, is an IVF treatment procedure. Using a similar pronuclear transfer technique, researchers at Newcastle University led by Douglass Turnbull successfully transplanted healthy DNA in human eggs from women with mitochondrial disease into the eggs of women donors who were unaffected. In such cases, ethical questions have been raised regarding biological motherhood, since the child receives genes and gene regulatory molecules from two different women. Using genetic engineering in attempts to produce babies free of mitochondrial disease is controversial in some circles and raises important ethical issues. A male baby was born in Mexico in 2016 from a mother with Leigh syndrome using MRT. In September 2012 a public consultation was launched in the UK to explore the ethical issues involved. Human genetic engineering was used on a small scale to allow infertile women with genetic defects in their mitochondria to have children. In June 2013, the United Kingdom government agreed to develop legislation that would legalize the 'three-person IVF' procedure as a treatment to fix or eliminate mitochondrial diseases that are passed on from mother to child. The procedure could be offered from 29 October 2015 once regulations had been established.

For services to the Care of Wildlife in Northumberland. Walter Wilson Ross, Conductor, Pension Silver Band, East Lothian. For services to Music. Charles Routledge, Dresser. For services to the Theatre. David Walton Routledge. For services to the community in Hillingdon, Middlesex. Harold Rowling. For services to the community in Westmeston, East Sussex. Shantilal Hirji Ruparell. For services to the community in Harrow, Middlesex. James Edwin Rous Saltonstall. For services to Yachting and to Young People. Anne Mary Sankaran. For services to the community in Oldham, Lancashire. Peter Saunders, Chairman, Groundwork Trust, Merthyr and Cynon. For services to the Environment. Alan Digerson Savage. For services to the Croydon Battle of Britain Memorial and to the Royal Air Force Benevolent Fund. John Robert Savage. For services to the community in Southwell, Nottinghamshire. Leslie Daniel Sayer, . For services to the Telegraphist Air Gunners' Association. Barry Scaplehorn, lately Firefighter, Suffolk County Fire Service. For services to the Fire Services Benevolent Fund. Susan Scarsbrook, Head, Sudbourne Primary School, Lambeth, London. For services to Education. David Andrew Seaman. For services to Association Football. Peter Jonathan Seaman, lately Chief Inspector, Hertfordshire Constabulary. For services to the Police. Sukumar Sen. For services to the community in Lochaber. Dorothy Sewell. For services to the community in Middlesbrough, North Yorkshire. Robert James Shaw. For services to the Fishing Industry. Patrick John Sherwin. For services to Coastal Rowing.

Spironolactone is widely used as an antiandrogen in feminizing hormone therapy for transfeminine people and is recommended by transgender medicine clinical guidelines for such purposes. It is the most commonly used antiandrogen in transfeminine people in the United States, whereas cyproterone acetate (CPA), which is not available in the United States, is widely used in Europe and throughout the rest of the world. Spironolactone is inferior to CPA, other progestogens, GnRH modulators, and high-dose parenteral estradiol monotherapy in terms of achieving adequate testosterone suppression in transfeminine people. However, spironolactone acts as a direct though weak androgen receptor antagonist rather than by suppressing testosterone levels, and hence its antiandrogenic effects and potential therapeutic benefits in this context are not necessarily reflected in testosterone levels. In any case, while widely used, there remain very limited comparative clinical data on spironolactone versus other antiandrogenic approaches in terms of physical feminization outcomes in transfeminine people.

Sources: en.wikipedia.org

Notes from published material

1950: Fujirebio (formerly Fujizoki Pharmaceutical, Co., Inc.) is founded in Tokyo, Japan. 1966: Launch of HA Ag (TPHA), the world's first hemagglutination test for syphilis. 1981: Established Fujirebio Taiwan Inc. 1987: Established Fujirebio America, Inc. (merged to Fujirebio Diagnostics, Inc.) in the United States. 1998: Acquisition of Centocor Diagnostics of Pennsylvania, Inc. (USA, currently Fujirebio Diagnostics, Inc.), pioneer in oncology testing and developer of CA125II, CA19-9 and CA15-3. 2006: Acquisition of CanAg Diagnostics AB (Sweden, currently Fujirebio Diagnostics AB), leader in oncology biomarker development. 2007: Launch of CL4800 in Japan to support blood screening for the Japanese Red Cross Society (~2019). 2008: Acquisition of Advanced Life Science Institute, Inc. 2008: Acquisition of American Biological Technologies, Inc. (merged to Fujirebio Diagnostics, Inc.). 2010: Acquisition of Innogenetics N.V. (Belgium, currently Fujirebio Europe N.V.), world leader in specialty molecular and immunoassay testing. 2017: Established Fujirebio Holdings, Inc., as parent company of Fujirebio Inc., Fujirebio Diagnostics, Inc., Fujirebio Europe N.V. and other Fujirebio group companies. 2019: Established Fujirebio Diagnostics Japan, Inc., focusing on OEM business in Japan. 2020: Established Fujirebio China Co., Ltd. 2022: Acquisition of ADx NeuroSciences. 2022: Acquisition of Fluxus, Inc. 2025: Acquisition of Plasma Services Group, Inc.

=== Claisen condensation and related reactions === Esters can undergo a variety of reactions with carbon nucleophiles. They react with an excess of a Grignard reagent to give tertiary alcohols. Esters also react readily with enolates. In the Claisen condensation, an enolate of one ester (1) will attack the carbonyl group of another ester (2) to give tetrahedral intermediate 3. The intermediate collapses, forcing out an alkoxide (R'O−) and producing β-keto ester 4.

== Artificial cartilage == Synthetic cartilage can be composed of many different materials that mimic its functional properties. Tissue engineering principles include the use of cells, growth factors, and synthetic scaffolds in order to do this.

== Medical uses == Etoperidone was used or was intended for use as an antidepressant in the treatment of depression. Etoperidone might be useful as a hallucinogen antidote or "trip killer" in blocking the effects of serotonergic psychedelics like psilocybin and lysergic acid diethylamide (LSD).

For non-small cell lung cancer, pembrolizumab is used in combination with chemotherapy (for all PD-L1, a PD-1 receptor ligand, levels) or by itself as a first-line treatment if the cancer expresses (≥ 1%) PD-L1 and the cancer has no mutations in EGFR or in ALK; if chemotherapy has already been administered, then pembrolizumab can be used as a second-line treatment, but if the cancer has EGFR or ALK mutations, agents targeting those mutations should be used first. Assessment of PD-L1 expression must be conducted with a validated and approved companion diagnostic.

Sources: en.wikipedia.org

Further detail

==== Data annotation and "ghost workers" ==== Beyond hardware, the development of AI models relies on massive amounts of human labour to label data, train algorithms, and moderate content. This work is frequently outsourced to business process outsourcing (BPO) firms operating in the Global South, particularly in countries like Kenya, Ethiopia, and Colombia. These data labourers, often referred to as "ghost workers", operate in what researchers describe as "digital sweatshops". Workers frequently report exploitative conditions, including low pay (sometimes as little as $2 an hour), forced unpaid overtime, and a lack of job security. Furthermore, content moderators are routinely exposed to graphic, violent, and hateful material in order to train AI safety filters. A 2025 Equidem survey of data workers documented widespread psychological harm, including PTSD, anxiety, and depression resulting from this exposure. In the UK, development experts and technology associations have argued that the UK has a responsibility to address these supply chain abuses. The Institute of Development Studies (IDS) has warned that the uncritical use of AI in international development is morally dubious, noting that AI is often built on "stolen data" labelled using the exploited labour of women in low-income countries. The IDS advocates for a "Responsible AI" approach that removes worker exploitation from the supply chain and ensures fair work practices. Furthermore, techUK, the UK's technology trade association, has criticised the UK Government for falling behind on supply chain regulation.

The Asian Federation for Psychotherapy published a code of ethics in 2008 with the following principles: Beneficence, Responsibility, Integrity, Justices, and Respect. Similar to the APA code, it provides detailed instructions for the conduct of psychologists, specifically psychotherapists. Russia, India, Iran, Kazakhstan, China, Malaysia, and Japan are member countries. The National Latina/o Psychological Association adopted their current ethical guidelines in 2018, stating that "the traditional Eurocentric foundations in mainstream psychology have provided culturally bound knowledge about worldviews, ways of living, and cultural practices." Their principles are: Respect and Responsibility, Ethical Dilemmas, Ethical Decision-Making and Legal Responsibility, Consultation, Justice and Advocacy, Self-Awareness and Social-Consciousness, Action and Accountability, Training and Creating Infrastructure, and Mentorship.

== Career == Cooks became an assistant professor at Kansas State University from 1968 to 1971. In 1971, he took a position at Purdue University. He became a professor of chemistry in 1980 and was appointed the Henry Bohn Hass Distinguished Professor in 1990. Cooks was co-editor of the Annual Review of Analytical Chemistry from 2013 to 2017.

==== Winter ==== Traditionally, the greatest varieties of kimchi were available during the winter. In preparation for the long winter months, many types of kimjang kimchi (김장 김치) were prepared in early winter and stored in the ground in large kimchi pots. Today, many city residents use modern kimchi refrigerators offering precise temperature controls to store kimjang kimchi. November and December are traditionally when people begin to make kimchi; women often gather together in each other's homes to help with winter kimchi preparations. "Baechu kimchi" is made with salted baechu filled with thin strips of radish, parsley, pine nuts, pears, chestnuts, shredded red pepper, manna lichen (Korean: 석이 버섯; RR: seogi beoseot), garlic, and ginger.

Sources: en.wikipedia.org

Frequently asked questions

What is Semax chemically?

It is a synthetic peptide of seven amino acids. Its backbone corresponds to a fragment of adrenocorticotropic hormone extended at the carboxyl end. The material is distributed as a lyophilized solid for laboratory use.

Why was the Pro-Gly-Pro tail added?

The extension was introduced to slow enzymatic breakdown of the peptide in biological systems. Natural ACTH fragments are degraded rapidly by peptidases. Adding the tripeptide was intended to extend the window during which the molecule remains intact.

How strong is the clinical evidence?

Most published work consists of animal experiments conducted in a small number of laboratories. Human data are limited in number and size. Whether the observed effects translate into reliable clinical benefit is still unresolved.

What receptor system does it engage?

It is associated with the melanocortin receptor family, particularly subtypes found in the central nervous system. This interaction is separate from the adrenal pathway activated by full-length ACTH.

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