This is a working overview of Semax, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-02-06 and is reviewed periodically as new material appears.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Contains one methionine sulfur atom |
| Molecular mass | Approximately 814 Da | Consistent with a seven-residue peptide |
| Appearance | White to off-white powder | Typical lyophilized form |
| Solubility | Freely soluble in water | Also soluble in dimethyl sulfoxide |
| Typical storage | -20 °C, desiccated | Limits methionine oxidation |
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.
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.
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.
== Accreditation == Aga Khan University Hospital, Karachi is a Joint Commission International (JCI) accredited hospital. This hospital is also accredited by the College of Physicians and Surgeons of Pakistan. Its Clinical Laboratories are also accredited by the College of American Pathologists (CAP).
the reduction of growth hormone and insulin-like growth factor 1 (somatomedin C) in adults with acromegaly who have had inadequate response to or cannot be treated with surgical resection, pituitary irradiation, and bromocriptine mesylate at maximally tolerated doses severe diarrhea/flushing episodes associated with metastatic carcinoid tumors in adults profuse watery diarrhea associated with vasoactive intestinal peptide tumors (VIPomas) in adults
Pharmacodynamics (PD) is the study of the biochemical and physiologic effects of drugs (especially pharmaceutical drugs). The effects can include those manifested within animals (including humans), microorganisms, or combinations of organisms (for example, infection). Pharmacodynamics and pharmacokinetics are the main branches of pharmacology, being itself a topic of biology interested in the study of the interactions of both endogenous and exogenous chemical substances with living organisms. In particular, pharmacodynamics is the study of how a drug affects an organism, whereas pharmacokinetics is the study of how the organism affects the drug. Both together influence dosing, benefit, and adverse effects. Pharmacodynamics is sometimes abbreviated as PD and pharmacokinetics as PK, especially in combined reference (for example, when speaking of PK/PD models). Pharmacodynamics places particular emphasis on dose–response relationships, that is, the relationships between drug concentration and effect. One dominant example is drug-receptor interactions as modeled by
=== Evolution of vertebrate hemoglobin === Scientists agree that the event that separated myoglobin from hemoglobin occurred after lampreys diverged from jawed vertebrates. This separation of myoglobin and hemoglobin allowed for the different functions of the two molecules to arise and develop: myoglobin has more to do with oxygen storage while hemoglobin is tasked with oxygen transport. The α- and β-like globin genes encode the individual subunits of the protein. The predecessors of these genes arose through another duplication event also after the gnathosome common ancestor derived from jawless fish, approximately 450–500 million years ago. Ancestral reconstruction studies suggest that the preduplication ancestor of the α and β genes was a dimer made up of identical globin subunits, which then evolved to assemble into a tetrameric architecture after the duplication. The development of α and β genes created the potential for hemoglobin to be composed of multiple distinct subunits, a physical composition central to hemoglobin's ability to transport oxygen. Having multiple subunits contributes to hemoglobin's ability to bind oxygen cooperatively as well as be regulated allosterically. Subsequently, the α gene also underwent a duplication event to form the HBA1 and HBA2 genes. These further duplications and divergences have created a diverse range of α- and β-like globin genes that are regulated so that certain forms occur at different stages of development.
Sources: en.wikipedia.org
== External links == Jeffries WB (1999-02-17). "Inverse Agonists for Medical Students". Office of Medical Education - Courses - IDC 105 Principles of Pharmacology. Creighton University School of Medicine - Department of Pharmacology. Retrieved 2008-08-12. Inverse Agonists: An Illustrated Tutorial Panesar K, Guzman F. Pharmacology Corner. 2012
== Susceptibility to infection == Pandemics such as COVID-19 show that people dramatically differ in their susceptibility to infection. This may be because of general health, age, or their immune status, e.g. when they have been infected previously. However, it also has become clear that there are genetic factors which determine susceptibility to infection. For instance, up to 40% of SARS-CoV-2 infections may be asymptomatic, suggesting that many people are naturally protected from disease. Large genetic studies have defined risk factors for severe SARS-CoV-2 infections, and genome sequences from 659 patients with severe COVID-19 revealed genetic variants that appear to be associated with life-threatening disease. One gene identified in these studies is type I interferon (IFN). Autoantibodies against type I IFNs were found in up to 13.7% of patients with life-threatening COVID-19, indicating that a complex interaction between genetics and the immune system is important for natural resistance to Covid. Similarly, mutations in the ERAP2 gene, encoding endoplasmic reticulum aminopeptidase 2, seem to increase the susceptibility to the plague, the disease caused by an infection with the bacteria Yersinia pestis. People who inherited two copies of a complete variant of the gene were twice as likely to have survived the plague as those who inherited two copies of a truncated variant. Susceptibility also determined the epidemiology of infection, given that different populations have different genetic and environmental conditions that affect infections.
=== Bosnian War === Hitchens cited the Bosnian War as monumentally changing his views on military intervention, commenting that for the first time he found himself on the side of neoconservatives. In an interview with Johann Hari he said:
=== Disinfectant === Hydrogen peroxide may be used for the sterilization of various surfaces, including surgical instruments, and may be deployed as a vapour (VHP) for room sterilization. H2O2 demonstrates broad-spectrum efficacy against viruses, bacteria, yeasts, and bacterial spores. In general, greater activity is seen against Gram-positive than Gram-negative bacteria; however, the presence of catalase or other peroxidases in these organisms may increase tolerance in the presence of lower concentrations. Lower levels of concentration (3%) will work against most spores; higher concentrations (7 to 30%) and longer contact times will improve sporicidal activity. Hydrogen peroxide is seen as an environmentally safe alternative to chlorine-based bleaches, as it degrades to form oxygen and water and it is generally recognized as safe as an antimicrobial agent by the U.S. Food and Drug Administration (FDA).
It was recommended for parents to safeguard their children by ensuring they have a smoke-free zone. One such way recommended for smokers to protect family, friends, and others is by smoking outside and showering and changing clothes before coming into contact with others. However, research has shown that parents who are heavy smokers (> 10 cigarettes per day) are less likely to believe that third-hand smoke is harmful to children. Third-hand smoke is one of the issues promoting indoor smoking bans, especially supported by performers such as musicians, who are forced to bring third-hand smoke contamination into their homes through contaminated instruments and cases.
Sources: en.wikipedia.org
=== March === 1 March COVID-19 in the UK Lockdown Files: WhatsApp messages leaked to the Daily Telegraph are reported as suggesting former Health Secretary Matt Hancock chose to ignore advice from experts in April 2020 that there should be "testing of all going into care homes". A spokesman for Hancock says "These stolen messages have been doctored to create a false story that Matt rejected clinical advice on care home testing". A Freedom of Information request by BBC News reveals that 729 sex offenders who were under supervision disappeared off the radar in a three-year period from 2019 to the end of 2021. 2 March COVID-19 in the UK: Lockdown Files: The Daily Telegraph publishes more of Matt Hancock's WhatsApp exchanges, this time with former education secretary Gavin Williamson in December 2020, when a debate into whether schools should reopen following the Christmas holiday was taking place. The leaked messages suggest Hancock favoured school closures, while Williamson was more hesitant. Hancock, who worked alongside journalist Isabel Oakeshott to co-author a book, describes the release of the messages as a "massive betrayal and breach of trust". In response, Oakeshott says she released the messages because she believed doing so was in the "public interest". Sir Keir Starmer unveils Sue Gray, who led the investigation into the Partygate scandal, as Labour's new chief of staff, sparking concern among some Conservative MPs about her impartiality.
=== 1870s === 1869/1870: American beekeeper Ellen Smith Tupper became the first female editor of an entomological journal. 1870: Katharine Murray Lyell was a British botanist, author of an early book on the worldwide distribution of ferns, and editor of volumes of the correspondence of several of the era's notable scientists. 1870: American engineer and chemist Ellen Swallow Richards became the first American woman to earn a degree in chemistry. 1870: Russian chemist Anna Volkova became the first female member of the Russian Chemical Society. 1874: Russian chemist Julia Lermontova became the first Russian woman to receive a PhD in chemistry. 1875: Hungarian archaeologist Zsófia Torma excavated the site of Turdaș-Luncă in Hunedoara County, today in Romania. The site, which uncovered valuable prehistoric artifacts, became one of the most important archaeological discoveries in Europe. 1876–1878: American naturalist Mary Treat studied insectivorous plants in Florida. Her contributions to the scientific understanding of how these plants caught and digested prey were acknowledged by Charles Darwin and Asa Gray. 1878: English entomologist Eleanor Anne Ormerod became the first female Fellow of the Royal Meteorological Society. A few years afterwards, she was appointed as Consulting Entomologist to the Royal Agricultural Society.
I hit him over the head with my 'rod of iron' (a section of the rear axle of an automobile)." Karriem recalled his children sobbed and begged him, "please, Daddy, don't do it, don't do it!" On November 22, press coverage included a picture of the "Voodoo house" where the slaying had occurred. It was revealed that he had taken on the name "Karriem", referring to "Harris" as his 'slave name'. His son has likewise been renamed Hasabas. Hasabas, age 12, and daughter Ruby, 9, had been forced to witness the ritual. Press reported: "With an insane light in his eyes, he admitted that he had planned to seek out and kill Judges Edward J. Jeffries and Arthur E Gordon for the purpose of propitiating jungle gods." Karriem also reported wanting to kill a 21 year old social worker who had cut him from welfare rolls. Karriem was compared to the Ahfed Abdullah, formerly James Moaning, described as psychopathic, who had gained entrance to the Mayor's home in the delusional belief that the Mayor was responsible for the government of Haiti. On November 23, press discussed police access to a temple on Hasting Street using a secret password, their raid on the temple, and their arrest of leader Ugan Ali, described as 'God of the Asiatics', after he admitted to having taught Karriem. Police initiated a manhunt for Fard and another leader, Ugan Ali, who were arrested and questioned. Karriem was deemed insane and committed to a mental hospital. "The society cannot be blamed for anything he did", Ali was quoted as saying in the Detroit News.
The pulmonary trunk divides into pulmonary arteries and progressively smaller arteries throughout the lungs, until it reaches capillaries. As these pass by alveoli carbon dioxide is exchanged for oxygen. This happens through the passive process of diffusion. In the left heart, oxygenated blood is returned to the left atrium via the pulmonary veins. It is then pumped into the left ventricle through the mitral valve and into the aorta through the aortic valve for systemic circulation. The aorta is a large artery that branches into many smaller arteries, arterioles, and ultimately capillaries. In the capillaries, oxygen and nutrients from blood are supplied to body cells for metabolism, and exchanged for carbon dioxide and waste products. Capillary blood, now deoxygenated, travels into venules and veins that ultimately collect in the superior and inferior vena cavae, and into the right heart.
== Pharmacology == Like Δ9-THC, 11-hydroxy-THC is a partial agonist at the cannabinoid receptor CB1, but with significantly higher binding affinity (Ki = 0.37 nM compared to Δ9-THC Ki = 35 nM). With respect to cAMP inhibition at CB1 it displays a similar potency to that of Δ9-THC (EC50 = 11 nM vs. EC50 = 5.2 nM, respectively), but a lower maximum response, i.e., efficacy (Emax = 28% vs. Emax = 70%).
Sources: en.wikipedia.org
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.
Most published work uses intranasal administration, matching the route of the registered Russian formulation. Some animal experiments use intravenous or intraperitoneal injection. The route matters because the intact peptide is cleared rapidly from blood, so exposure differs between methods.
A purity value describes the share of the powder accounted for by the target peptide, usually by high-performance liquid chromatography. It does not confirm that the sequence is correct, which requires mass spectrometry or amino acid analysis. Purity and identity are separate checks.
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.