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 2026-02-05 and is reviewed periodically as new material appears.
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.
Solid semax is typically supplied as a lyophilised powder that is hygroscopic and sensitive to moisture, light, and repeated temperature cycling. Long-term storage of the dry peptide is generally recommended at approximately -20 degrees Celsius, while shorter working periods may use refrigeration at 2 to 8 degrees Celsius. Vials should remain tightly closed and desiccated when brought to room temperature, because condensation can damage the material before it is weighed. Dividing a batch into aliquots is preferable to thawing one container repeatedly.
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.
| Property | Value | Notes |
|---|---|---|
| Sequence | Met-Glu-His-Phe-Pro-Gly-Pro | Heptapeptide; ACTH(4-10) analog extended at C-terminus |
| Molecular mass | ~813.9 Da | Free peptide, unmodified |
| Appearance | White to off-white powder | Typical lyophilized solid |
| Solubility | Soluble in water and saline | Also soluble in common aqueous buffers |
| Storage (solid) | -20 °C, desiccated | Protect from moisture and repeated thawing |
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.
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.
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.
稳定性主要由水解与氧化两条路径支配。肽键在中性或弱酸性条件下相对稳定，遇到强碱或长时间高温则明显断裂；甲硫氨酸侧链容易被氧化成亚砜，使主峰前移并拉低实际含量。金属离子、光照和反复冻融会进一步促进降解或聚集。冻干粉在低温避光条件下可存放较长时间，配制后的水溶液通常需要冷藏并尽快用完。
纯度评估以反相高效液相色谱为主，通过主峰面积百分比给出粗略结果，再配合电喷雾质谱核对分子量。氨基酸分析可验证组成比例，手性色谱或毛细管电泳用于检查残基构型。常见杂质包括缺失序列的短肽、氧化产物与二聚体。由于多数市售品不附带完整检验报告，独立第三方检测常被用来核实标称值。
=== Cleaning === Cleaning of human remains varies by type. If necessary, surface cleaning of bone can be done with a very mild detergent and water solution, but bones should never be soaked in order to prevent dirt from becoming embedded in pores. The possibility of cleaning human remains is highly dependent on the fragility of the specimen.
== History == In the early 1920s, several groups noted that pancreatic extracts injected into diabetic animals would result in a brief increase in blood sugar prior to the insulin-driven decrease in blood sugar. In 1922, C. Kimball and John R. Murlin identified a component of pancreatic extracts responsible for this blood sugar increase, terming it "glucagon", a portmanteau of "glucose agonist". In the 1950s, scientists at Eli Lilly isolated pure glucagon, crystallized it, and determined its amino acid sequence. This led to the development of the first radioimmunoassay for detecting glucagon, described by Roger Unger's group in 1959. A more complete understanding of its role in physiology and disease was not established until the 1970s, when a specific radioimmunoassay was developed. In 1979, while working in Joel Habener's laboratory at Massachusetts General Hospital, Richard Goodman collected islet cells from Brockman bodies of American anglerfish in order to investigate somatostatin. By splicing DNA from anglerfish islet cells into bacteria, Goodman was able to identify the gene which codes for somatostatin. P. Kay Lund joined the Habener lab and used Goodman's bacteria to search for the gene for glucagon. In 1982, Lund and Goodman published their discovery that the proglucagon gene codes for three distinct peptides: glucagon and two novel peptides. Graeme Bell at Chiron Corporation led a team which isolated the two latter peptides, which are now known as glucagon-like peptide-1 and glucagon-like peptide-2.
It was determined that this preparation behaved anomalously in certain immunoassays and was not suitable as an IS. Three different human pituitary extracts containing prolactin were subsequently obtained as candidates for an IS. These were distributed into ampoules coded 83/562, 83/573, and 84/500. Collaborative studies involving 20 different laboratories found little difference between these three preparations. 83/562 appeared to be the most stable. This preparation was largely free of dimers and polymers of prolactin. On the basis of these investigations, 83/562 was established as the Second IS for human prolactin. Once stocks of these ampoules were depleted, 84/500 was established as the Third IS for human prolactin. 84/500 has nearly run out and in 2016 replacement was proposed. The new 83/573 contains 67.2 mIU per ampoule when calibrated against the third IS and contains 1.002 g of human pituitary extract each (which is then lyophilized). Each ampoule contains approximately 3.2 μg of prolactin. The assigned value will be 67 mIU per ampoule. If a fifth IS is needed, it will likely be based on recombinant protein, as WHO has not received any further donations of human pituitary extracts.
An ideal drug delivery system should have effective targeting and controlled release. The two main targeting strategies are passive targeting and active targeting. Passive targeting depends on the fact that tumors have abnormally structured blood vessels that favor accumulation of relatively large macromolecules and nanoparticles. This so-called enhanced permeability and retention effect (EPR) allows the drug-carrier be transported specifically to the tumor cells. Active targeting is, as the name suggests, much more specific and is achieved by taking advantage of receptor-ligand interactions at the surface of the cell membrane. Controlled drug release systems can be achieved through several methods. Rate-programmed drug delivery systems are tuned to the diffusivity of active agents across the membrane. Another delivery-release mechanism is activation-modulated drug delivery, where the release is triggered by environmental stimuli. The stimuli can be external, such as the introduction of a chemical activators or activation by light or electromagnetic fields, or biological - such as pH, temperature, and osmotic pressure which can vary widely throughout the body.
Sources: en.wikipedia.org
When the neurotransmitter glutamate binds to the NMDA receptor, and the postsynaptic cell membrane is depolarized (from the postsynaptic cell being activated), the magnesium block in the NMDA receptor channel is displaced. Calcium (Ca2+) and sodium (Na+) can enter the cell via the open channel, while potassium (K+) can exit the cell. Etoxadrol antagonizes the NMDA receptor by binding to the PCP site, located just above the magnesium block in the ion channel. In the event that the magnesium block is displaced, etoxadrol blocks the NMDA receptor channel, preventing cations from entering or exiting the channel. This mechanism of action also applies to PCP, TCP, ketamine and dexoxadrol. Etoxadrol binding does not affect the binding affinity of other sites on the NMDA receptor, as found by binding studies showing the displacement of radiolabeled TCP by etoxadrol (TCP binding in the absence of etoxadrol: Ki = 19.2 × 10−9 M, Bmax = 1.36 pmol/mg protein; TCP binding in the presence of etoxadrol: Ki = 21.7 × 10−9 M, Bmax = .66 pmol/mg protein). Despite its anesthetic and analgesic effects, etoxadrol does not interact with benzodiazepine, muscarinic acetylcholine, or mu opioid receptors. However, etoxadrol may act in the dopamine reward pathway, explaining its reinforcing properties.
Animation – Ratchet & Clank: Rift Apart Artistic Achievement – The Artful Escape Audio Achievement – Returnal Best Game – Returnal British Game – Forza Horizon 5 Debut Game – TOEM EE Game of the Year – Unpacking Evolving Game – No Man's Sky Family – Chicory: A Colorful Tale Game Beyond Entertainment – Before Your Eyes Game Design – Inscryption Multiplayer – It Takes Two Music – Returnal Narrative – Unpacking Original Property – It Takes Two Performer in a Leading Role – Jane Perry as Selene Vassos in Returnal Performer in a Supporting Role – Kimberly Brooks as Hollis Forsythe in Psychonauts 2 Technical Achievement – Ratchet & Clank: Rift Apart
The tissue is then prepared for viewing under a microscope using either chemical fixation or frozen section. If a large sample is provided e.g. from a surgical procedure then a pathologist looks at the tissue sample and selects the part most likely to yield a useful and accurate diagnosis - this part is removed for examination in a process commonly known as grossing or cut up. Larger samples are cut to correctly situate their anatomical structures in the cassette. Certain specimens (especially biopsies) can undergo agar pre-embedding to assure correct tissue orientation in cassette & then in the block & then on the diagnostic microscopy slide. This is then placed into a plastic cassette for most of the rest of the process.
== Engineering concepts == The prospect of engineering various metabolic pathways into mammals which do not possess them is a topic of great interest for bio-engineers today. The glyoxylate cycle is one of the pathways which engineers have attempted to manipulate into mammalian cells. This is primarily of interest for engineers in order to increase the production of wool in sheep, which is limited by the access to stores of glucose. By introducing the pathway into sheep, the large stores of acetate in cells could be used in order to synthesize glucose through the cycle, allowing for increased production of wool. Mammals are incapable of executing the pathway due to the lack of two enzymes, isocitrate lyase and malate synthase, which are needed in order for the cycle to take place. It is believed by some that the genes to produce these enzymes, however, are pseudogenic in mammals, meaning that the gene is not necessarily absent, rather, it is merely "turned off". In order to engineer the pathway into cells, the genes responsible for coding for the enzymes had to be isolated and sequenced, which was done using the bacteria E.coli, from which the AceA gene, responsible for encoding for isocitrate lyase, and the AceB gene, responsible for encoding for malate synthase were sequenced.
Inquiries sent to the IDF regarding the experiences of these health care workers received a statement from a spokesperson that did not directly confirm whether investigations into the shootings of preteen children had been conducted or if any soldiers faced disciplinary action for firing at them. In response to claims alleging that the report was based on "fabricated evidence", The New York Times issued a statement defending the integrity of the piece, emphasizing that it had undergone rigorous editing and verification, including consultations with experts and the use of supporting photographs, which they deemed "too horrific for publication." De Volkskrant interviewed 17 doctors who had volunteered during the Gaza war. Fifteen of them reported seeing children with "a single gunshot wound to the head and/or chest." These doctors reported seeing 114 children injured this way. In response, former Commander of the Royal Netherlands Army Mart de Kruif told the paper, "If you're seeing a high number of gunshot wounds to the chest area and the head, that’s not collateral damage – that’s deliberate targeting." In one documented case, a girl was reportedly shot and killed while in her mother's arms. In June 2026, a 94-page report by the UN Independent International Commission of Inquiry on the Occupied Palestinian Territory concluded there were reasonable grounds to determine that Israeli forces directly targeted children in Gaza using snipers and quadcopter drones.
Sources: en.wikipedia.org
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.
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.
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.
Dry powder is usually kept at about -20 degrees Celsius for long-term storage and at 2 to 8 degrees Celsius for short working periods. Containers should stay sealed and protected from light and moisture to limit degradation.