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Semax Structure And Research Background — Deep Dive

By Editorial Desk · published 2026-05-26 · last reviewed 2026-06-11 · Topic

The short version of ACTH fragment fits in a sentence. The long version — which is the one that helps — is below.

This page was last updated on 2026-06-11 and is reviewed periodically as new material appears.

Semax Structure and Research Background

Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its chain combines the first seven residues of corticotropin with a C-terminal proline-glycine-proline extension, a modification intended to slow enzymatic breakdown. The free peptide has a molecular mass near 813.9 daltons. It belongs to the class of ACTH-derived fragments studied for central nervous system activity rather than for adrenal steroid stimulation. This structural relationship to a natural hormone fragment is the usual starting point for describing the compound in the literature.

Development took place during the 1980s at institutes of the Russian Academy of Sciences, where peptide fragments of ACTH were screened for cognitive and neuroprotective effects. The compound received regulatory approval in Russia as a nasal preparation, marketed for conditions such as ischemic stroke, transient ischemic attacks, and optic nerve disorders. Registration in other countries has not followed. Most published clinical reports originate from a small number of Russian research groups, and independent replication outside that setting remains limited. The regulatory status therefore differs sharply between Russia and the rest of the world.

Semax Background and Chemistry

Laboratory descriptions of the material are consistent across suppliers. It appears as a white to off-white lyophilized powder that dissolves readily in water and in polar organic solvents such as dimethyl sulfoxide. Aqueous solutions are clear and colorless at low concentrations. Because the peptide contains methionine, oxidation at the sulfur atom is a recognized degradation pathway, and handling notes usually call for protected, desiccated storage. Reported purity for research-grade lots is generally above 95 percent as measured by reversed-phase high-performance liquid chromatography.

The compound is registered in Russia as a pharmaceutical product, most commonly formulated as a nasal solution, and has been used in that setting since the 1990s. Outside that jurisdiction it is generally handled as a research chemical rather than an approved medicine. Regulatory status therefore differs sharply between countries, and material sold internationally may not correspond to the Russian pharmaceutical formulation. Documentation with commercial samples is typically limited to a certificate of analysis covering purity and identity, not clinical status or local legal classification.

Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It corresponds to the ACTH(4-7) fragment extended at the C-terminus by a Pro-Gly-Pro tripeptide, an addition intended to slow enzymatic breakdown. The molecular formula is C37H51N9O10S and the molecular mass is approximately 814 daltons. In the literature it is often described as an ACTH(4-10) analog, although that label reflects a naming convention as much as a precise structural relationship. The compound was developed in Russia and remains most closely associated with that research tradition.

Semax at a glance

PropertyValueNotes
SequenceMet-Glu-His-Phe-Pro-Gly-ProHeptapeptide; ACTH(4-10) analog extended at C-terminus
Molecular mass~813.9 DaFree peptide, unmodified
AppearanceWhite to off-white powderTypical lyophilized solid
SolubilitySoluble in water and salineAlso soluble in common aqueous buffers
Storage (solid)-20 °C, desiccatedProtect from moisture and repeated thawing

Chemical Identity and Research Background

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.

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Semax Peptide Structure and Origin

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.

Further detail

However, it is also in contrast to higher doses of doxepin (50 to 300 mg/day), which have been found to significantly reduce latency to sleep onset. A positive dose–response relationship on sleep measures was observed for doses of doxepin between 1 and 6 mg in clinical studies, whereas the incidence of adverse effects remained constant across this dose range in both young and older adults. However, the incidence of adverse effects appeared to increase with longer treatment duration. A dose of doxepin as low as 1 mg/day was found to significantly improve most of the assessed sleep measures, but unlike the 3 and 6 mg/day doses, was not able to improve wake time during sleep. This, along with greater effect sizes with the higher doses, was likely the basis for the approval of the 3 and 6 mg doses of doxepin for insomnia and not the 1 mg dose. At very low doses, doxepin has not shown discontinuation or withdrawal effects nor rebound insomnia. Sustained effectiveness without apparent tolerance was demonstrated in clinical studies of up to 12 weeks duration. This appears to be in contrast to over-the-counter antihistamines like diphenhydramine and doxylamine and all other first-generation antihistamines, which are associated with rapid development of tolerance and dependence (by day 3 or 4 of continuous dosing) and loss of hypnotic effectiveness. It is for this reason that, unlike doxepin, they are not recommended for the chronic management of insomnia and are advised for only short-term treatment (i.e., 1 week).

At the start of 2016, experts warned the Philippines was at risk of having the Islamic State of Iraq and Syria (ISIS) set a foothold in the country. However, Duterte's predecessor, President Aquino III, dismissed the perpetrators of a March 2016 armed attack against the military as mere "mercenaries" wanting to join the ISIS. The earliest terrorist attacks in Duterte's presidency occurred in September 2016 in Davao City; November 2016 in Butig, Lanao del Sur; and in April to May 2017 in Inabanga, Bohol, where the Abu Sayyaf Group (ASG) attempted to establish a position in the Visayas. Though the military eventually quelled the sieges, the events were only a prelude to what would become Duterte's greatest challenge in combating terrorism.

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=== Category:EC 6.2 (form carbon–sulfur bonds) === EC 6.2.1.1: Acetate—CoA ligase EC 6.2.1.2: Medium-chain acyl—CoA ligase EC 6.2.1.3: Long-chain-fatty-acid—CoA ligase EC 6.2.1.4: Succinate—CoA ligase (GDP-forming) EC 6.2.1.5: Succinate—CoA ligase (ADP-forming) EC 6.2.1.6: Glutarate—CoA ligase EC 6.2.1.7: Cholate—CoA ligase EC 6.2.1.8: Oxalate—CoA ligase EC 6.2.1.9: Malate—CoA ligase EC 6.2.1.10: Acid—CoA ligase (GDP-forming) EC 6.2.1.11: Biotin—CoA ligase EC 6.2.1.12: 4-Coumarate—CoA ligase EC 6.2.1.13: Acetate—CoA ligase (ADP-forming) EC 6.2.1.14: 6-carboxyhexanoate—CoA ligase EC 6.2.1.15: Arachidonate—CoA ligase EC 6.2.1.16: Acetoacetate—CoA ligase EC 6.2.1.17: Propionate—CoA ligase EC 6.2.1.18: Citrate—CoA ligase EC 6.2.1.19: Long-chain-fatty-acid-luciferin-component ligase EC 6.2.1.20: Long-chain-fatty-acid-(acyl-carrier-protein) ligase EC 6.2.1.21: Transferred entry: 6.2.1.30 EC 6.2.1.22: (citrate (pro-3S)-lyase) ligase EC 6.2.1.23: Dicarboxylate—CoA ligase EC 6.2.1.24: Phytanate—CoA ligase EC 6.2.1.25: Benzoate—CoA ligase EC 6.2.1.26: o-Succinylbenzoate—CoA ligase EC 6.2.1.27: 4-hydroxybenzoate—CoA ligase EC 6.2.1.28: 3-alpha,7-alpha-dihydroxy-5-beta-cholestanate—CoA ligase EC 6.2.1.29: Transferred entry: 6.2.1.7 EC 6.2.1.30: Phenylacetate—CoA ligase EC 6.2.1.31: 2-furoate—CoA ligase EC 6.2.1.32: Anthranilate—CoA ligase EC 6.2.1.33: 4-chlorobenzoate—CoA ligase EC 6.2.1.34: trans-Feruloyl—CoA synthase EC 6.2.1.35: ACP-SH:acetate ligase EC 6.2.1.36: 3-hydroxypropionyl-CoA synthase EC 6.2.1.37: 3-hydroxybenzoate—CoA ligase EC 6.2.1.38: (2,2,3-trimethyl-5-oxocyclopent-3-enyl)acetyl-CoA synthase EC 6.2.1.39: (butirosin acyl-carrier protein)—L-glutamate ligase EC 6.2.1.40: 4-Hydroxybutyrate—CoA ligase EC 6.2.1.41: 3-((3aS,4S,7aS)-7a-methyl-1,5-dioxo-octahydro-1H-inden-4-yl)propanoate—CoA ligase EC 6.2.1.42: 3-oxocholest-4-en-26-oate—CoA ligase EC 6.2.1.43: 2-hydroxy-7-methoxy-5-methyl-1-naphthoate—CoA ligase EC 6.2.1.44: 3-(methylthio)propionyl—CoA ligase EC 6.2.1.45: E1 ubiquitin-activating enzyme EC 6.2.1.46: L-allo-Isoleucine—holo-CmaA peptidyl-carrier protein ligase EC 6.2.1.47: Medium-chain-fatty-acid-(acyl-carrier-protein) ligase EC 6.2.1.48: Carnitine—CoA ligase EC 6.2.1.49: Long-chain fatty acid adenylyltransferase FadD28 EC 6.2.1.50: 4-hydroxybenzoate adenylyltransferase FadD22 EC 6.2.1.51: 4-hydroxyphenylalkanoate adenylyltransferase FadD29 EC 6.2.1.52: L-Firefly luciferin—CoA ligase EC 6.2.1.53: L-Proline—L-prolyl-carrier protein ligase EC 6.2.1.54: D-Alanine—D-alanyl-carrier protein ligase EC 6.2.1.55: E1 SAMP-activating enzyme

Sources: en.wikipedia.org

Supporting material

The 'Dunkin' Donut' with a handle fashioned on it was discontinued in 2003 (except in Singapore) because it was hand-cut and uneconomical compared to machine-cut doughnuts. In 2004, the company's headquarters were relocated to Canton, Massachusetts. In December 2005, Dunkin' Donuts and Baskin-Robbins (by then, operating under the name Dunkin' Brands) were sold to a private equity consortium of Bain Capital, Carlyle Group, and Thomas H. Lee Partners for $2.4 billion. By 2010, Dunkin' Donuts' global sales were $6 billion. In June 2013, Dunkin' Donuts unveiled a new store design, the brand's first in almost seven years. The Dunkin' Donuts location in Natick, Massachusetts launched a program to test the concept of curbside pickup in December 2016. In January 2018, Dunkin' Donuts started opening new concept locations, beginning in Quincy, featuring modern decor, cold beverages on tap and a single-cup brewing machine, more packaged takeout options, and dedicated pick-up lines for mobile ordering inside and in the drive-thru. The concept was described as being part of a shift towards becoming an "on-the-go, beverage-led brand". In addition, the location, as well as others, began to trial signage referring to the chain as simply "Dunkin'"—removing "Donuts" from the name. In February 2018, Dunkin' announced plans to phase out polystyrene foam cups globally for environmental purposes by April 2020. In July 2018, Dave Hoffmann took over from Nigel Travis to become the CEO.

=== Nutritional fortification === Breakfast cereals may be fortified with dietary minerals and vitamins. For example, breakfast cereal in Canada may be fortified with specific micronutrient amounts per 100 grams of cereal, including thiamin, (2.0 mg), niacin (4.8 mg), and vitamin B6 (0.6 mg), among others.

=== Pencil drawing === The pencil-on-paper technique is arguably the simplest and most accessible way of creating electrodes on paper-based microfluidics as it uses inexpensive, common office supplies. Here, graphitic circuitry is created on the paper-based microfluidic device by repeatedly sketching with a pencil. For example, this electrical integration method was used in a completely hand-drawn paper microfluidic device for point-of-care cancer screening. This solvent-free technique allows the potential to create improvised paper-based μTAS. However, pencil-on-paper can also lead to a non-uniform deposition of graphite, limiting the performance of these hand-drawn circuits. Additionally, even though the process can be automated, the repeated drawing procedure is poorly scalable.

== Awards and honors == Raphael Katzen Award, Society for Industrial Microbiology, 2009. Fellow, Class of 2008, American Society for the Advancement of Science (AAAS). Featured profile, Nature Biotechnology, November 2007. Fellow, Society of Industrial Microbiology, 2003. College of Fellows, Class of 2001, American Institute of Medical and Biological Engineering (AIMBE).

Jessie Gordon, formerly McTavish, (born c.1940) is a Scottish retired nurse who was convicted in 1974 of murdering a patient with insulin, and of administering a variety of substances with intent to cause harm. The conviction was overturned on appeal in 1976. She was dubbed the "Angel of Death" by the press.

Sources: en.wikipedia.org

Notes from published material

3-Methylcrotonyl-CoA (β-Methylcrotonyl-CoA or MC-CoA) is an intermediate in the metabolism of leucine. It is found in mitochondria, where it is formed from isovaleryl-coenzyme A by isovaleryl coenzyme A dehydrogenase. It then reacts with CO2 to yield 3-methylglutaconyl-CoA, catalysed by 3-Methylcrotonyl-CoA carboxylase.

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=== Blue Men of Lurgan === The "blue men of Lurgan" were a pair of Lurgan men suffering from what was described as "familial idiopathic methemoglobinemia" who were treated by James Deeny in 1942. Deeny, who would later become the Chief Medical Officer of the Republic of Ireland, prescribed a course of ascorbic acid and sodium bicarbonate. In case one, by the eighth day of treatments, there was a marked change in appearance, and by the twelfth day of treatment, the patient's complexion was normal. In case two, the patient's complexion reached normality over a month-long duration of treatment.

The heavy isotope plutonium-244 has a half-life long enough that extreme trace quantities should have survived primordially (from the Earth's formation) to the present, but so far experiments have not yet been sensitive enough to detect it. Both plutonium-239 and plutonium-241 are fissile, meaning they can sustain a nuclear chain reaction, leading to applications in nuclear weapons and nuclear reactors. Plutonium-240 has a high rate of spontaneous fission, raising the neutron flux of any sample containing it. The presence of plutonium-240 limits a plutonium sample's usability for weapons or its quality as reactor fuel, and the percentage of plutonium-240 determines its grade (weapons-grade, fuel-grade, or reactor-grade). Plutonium-238 has a half-life of 87.7 years and emits alpha particles. It is a heat source in radioisotope thermoelectric generators, which are used to power some spacecraft. Plutonium isotopes are expensive and inconvenient to separate, so particular isotopes are usually manufactured in specialized reactors. Producing plutonium in useful quantities for the first time was a major part of the Manhattan Project during World War II that developed the first atomic bombs. The Fat Man bombs used in the Trinity nuclear test in July 1945, and in the bombing of Nagasaki in August 1945, had plutonium cores. Human radiation experiments studying plutonium were conducted without informed consent, and several criticality accidents, some lethal, occurred after the war.

Sources: en.wikipedia.org

Frequently asked questions

What is semax?

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.

How is semax related to ACTH?

Its sequence corresponds to the 4-10 region of corticotropin extended by three residues. This fragment lacks the region responsible for adrenal steroid release, so it is explored for neural rather than hormonal effects. The relationship explains the compound's classification among ACTH-derived peptides.

Is semax an approved drug?

It holds approval in Russia for several neurological indications as a nasal spray or drop formulation. Regulatory agencies in the United States and the European Union have not approved it. Products sold elsewhere are generally labeled for research use only.

Is semax an approved medicine?

It is registered as a pharmaceutical product in Russia, where it is typically supplied as a nasal solution. In most other countries it is not an approved drug and is traded as a research chemical instead. Approval status depends entirely on the jurisdiction involved.

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