A practical reference on Semax: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-01-26 and is reviewed periodically as new material appears.
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.
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.
当时的短肽研究普遍关注能否穿越血脑屏障、在低剂量下产生中枢效应，Semax 属于这一路线。鼻内给药是其主要使用方式，俄语文献报道的适应症涵盖缺血性卒中、短暂性脑缺血发作、认知功能减退以及视神经病变。这些研究大多发表在当地期刊上，样本规模与终点设置同西方试验惯例存在差异，国际同行对其临床证据的强度看法不一。
各国监管态度分化明显。俄罗斯按处方药管理，部分东欧国家留有使用记录；欧盟与美国未批准其作为药物上市，市面流通品通常标注为研究用化学品。身份差异意味着标示含量、纯度与无菌性缺少统一核查。体育领域还牵涉反兴奋剂名录，跨境携带则受目的地药品法规约束。
Semax 是人工设计的七肽，序列为 Met-Glu-His-Phe-Pro-Gly-Pro，骨架取自促肾上腺皮质激素片段 ACTH(4-10)。它于二十世纪八十年代在苏联的分子遗传学研究机构内合成。设计目标是保留该片段与注意力和记忆相关的活性，同时剔除促皮质激素释放等内分泌作用。此后俄罗斯将其登记为药品并进入临床使用。
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Seven-residue peptide |
| Molecular mass | 813.9 Da | Monoisotopic value |
| Appearance | White to off-white powder | Lyophilized form |
| Solubility | Freely soluble in water | Also soluble in saline and polar solvents |
| Storage (dry) | -20 °C or lower | Desiccated, protected from light |
Scientific literature on semax is unevenly distributed. A substantial share of published work originates from a small number of laboratories in Russia, while independent replication elsewhere is limited. Human data consist mostly of small trials with short follow-up, and several reported outcomes rely on subjective rating scales. Questions about how much intact peptide reaches the central nervous system after nasal administration, and how long it persists there, are still unresolved. The compound is best described as an active research subject rather than a settled pharmacological agent.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It was derived from the ACTH(4-10) fragment, a short segment of adrenocorticotropic hormone that lacks the hormonal activity associated with the full-length peptide. Researchers at the Institute of Molecular Genetics in Moscow developed the compound during the 1980s. It has been registered as a pharmaceutical product in Russia and several neighbouring countries, where it is supplied as a nasal solution, and it is also sold internationally as a research chemical.
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.
Pharmacological accounts link semax to melanocortin signalling and to modulation of neurotrophic factor expression, particularly brain-derived neurotrophic factor and nerve growth factor. Much of this evidence comes from rodent studies using intranasal delivery, a route chosen because it allows peptides to reach the central nervous system with limited systemic exposure. Whether the same mechanisms operate in humans at comparable magnitude remains an open question. The precise receptor or receptors responsible for the reported behavioural and neuroprotective effects have not been conclusively identified.
Clinical reports describe use in ischaemic stroke, transient ischaemic attack, optic nerve conditions, and cognitive complaints, but most of these studies are small and were conducted in a single region. Systematic reviews have generally described the evidence base as limited in size and variable in methodological quality. Randomised controlled data suitable for international regulatory assessment are scarce. As a result, major treatment guidelines outside Russia do not include the peptide, and interest in it remains largely research-driven rather than routine clinical.
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. It was developed as a fragment analog of adrenocorticotropic hormone, modeled specifically on the ACTH(4-10) region. The first four residues reproduce that fragment, while a Pro-Gly-Pro tripeptide is appended at the C-terminus. Work on the compound originated in Russia, where it entered clinical use as an intranasal preparation. Its sequence places it among short regulatory peptides studied for effects on the central nervous system rather than on the adrenal axis.
The C-terminal Pro-Gly-Pro extension is not incidental. Proline-rich tails are known to resist several common peptidases, and the published literature attributes the longer half-life of Semax, relative to unmodified ACTH fragments, to this feature. The modification also removes the melanocyte-stimulating and corticosteroidogenic activity that characterizes longer ACTH-derived sequences. Because the molecule is small and hydrophilic, it is typically formulated as an aqueous solution for intranasal or parenteral delivery. Acetylation or amidation at the termini appears in closely related research peptides and shifts the mass by a fixed increment.
Reported pharmacological work centers on neurotrophic signaling, including changes in BDNF and NGF expression in hippocampal tissue in animal models. Human data come largely from studies conducted in Russia, and how well those results generalize to other populations remains an open question. Regulatory status differs sharply by jurisdiction: Semax is a registered prescription medicine in Russia, while it holds no approved marketing status in the United States or the European Union. Outside such jurisdictions it is generally handled as a research chemical, which affects both documentation and quality expectations.
In January 2023, Foreign Minister Mauro Vieira announced Brazil's return to the Community of Latin American and Caribbean States (CELAC). During the 7th CELAC summit, Lula expressed support for a modernization of the South American customs union Mercosur and the creation of a common unit of account between Argentina and Brazil which other South American nations could also join to boost regional integration and skip US dollar dominance. On 25 January, during a trip to Uruguay, Lula called for the European Union-Mercosur trade deal to be sealed and a China-Mercosur trade agreement to be explored. Lula and Uruguayan president Luis Lacalle Pou held talks over infrastructure projects to be developed in Uruguay, including a joint Uruguayan-Brazilian administration of the Rivera International Airport. In March 2023, Uruguayan and Brazilian top officials jointly detailed the said infrastructure projects in Brasília. Brazil also invited Paraguay and Uruguay to join the works of the G20 ahead of the 2024 G20 Brazil summit, as Brazilian rotating presidency in the group was to begin on 1 December 2023. In December 2024, during a summit in Montevideo attended by Lula and Ursula von der Leyen, Mercosur struck a definitive free trade agreement with the European Union representing nearly a quarter of the global gross domestic product (GDP).
=== Phase 1 === AZD-4041 – orexin OX1 receptor antagonist – opioid-related disorders BI-1356225 – ghrelin O-acyltransferase (GOAT) inhibitor – opioid-related disorders Cebranopadol (GRT-6005; PRK-101; TRN-228) – μ-opioid receptor agonist, nociceptin receptor agonist – substance-related disorders CSX-1004 – monoclonal antibody against fentanyl – opioid-related disorders Dimethyltryptamine/harmine (DMT/harmine; RE-01) – combination of dimethyltryptamine (DMT) (serotonin 5-HT2A receptor agonist and serotonergic psychedelic) and harmine (monoamine oxidase inhibitor (MAOI) and other actions) – cocaine-related disorders DPI-125 (MCP-201) – μ-opioid receptor agonist, δ-opioid receptor agonist, κ-opioid receptor agonist – opioid-related disorders Ibuprofen/ketotifen (SJP-005) – combination of ibuprofen (cyclooxygenase (COX) inhibitor/NSAID) and ketotifen (histamine H1 receptor antagonist, other actions) – opioid-related disorders Icalcaprant (ABBV-1354; CVL-354) – κ-opioid receptor antagonist – opioid-related disorders KNX-100 (SOC-1) – oxytocin-like drug / indirect oxytocin receptor modulator – opioid-related disorders, substance-related disorders Mavoglurant (AFQ-056; STP-7) – metabotropic glutamate mGlu5 receptor antagonist – cocaine-related disorders MEB-1170 – μ-opioid receptor biased agonist – opioid-related disorders Mebufotenin (5-MeO-DMT) – non-selective serotonin receptor agonist, serotonin 5-HT1A and 5-HT2A receptor agonist, and serotonergic psychedelic – substance use disorders MST-01 – undefined mechanism of action – smoking withdrawal Nalmefene (AV-104; TH-104) – μ-opioid receptor antagonist, κ-opioid receptor weak partial agonist – opioid-related disorders Naltrexone implantable pellets (BICX-102, BICX-104) – opioid receptor antagonist – alcoholism, opioid-related disorders, substance-related disorders Nezavist (DCUK-OEt) – peripherally selective GABAA receptor positive allosteric modulator (etomidate site) – alcoholism Noribogaine (DMX-1001) – various actions – alcoholism NRS-033 (nalmefene prodrug) – μ-opioid receptor antagonist, κ-opioid receptor weak partial agonist – opioid-related disorders OMS-527 (OMS-182399; OMS527) – phosphodiesterase PDE7 inhibitor – cocaine-related disorders Psilocybin (MLS-101/MLS101) – non-selective serotonin receptor agonist, serotonin 5-HT2A receptor agonist, serotonergic psychedelic – opioid-related disorders Smoking cessation therapeutics - Astraea Therapeutics – nicotinic acetylcholine receptor antagonists – smoking withdrawal SXC-2023 – cystine/glutamate transporter (SLC7A11) – cocaine-related disorders Tezampanel (LY-293558; NGX-424; PRN-001-01) – ionotropic glutamate AMPA and kainate receptor antagonist – opioid-related disorders Zabaglurant (Heptares 25; HTL-0014242; HTL14242; TMP-301) – metabotropic glutamate mGlu5 receptor negative allosteric modulator – cocaine-related disorders, substance-related disorders
In crystallography, polymorphism is the phenomenon where a compound can crystallize into more than one crystal structure; in the case of elements the term allotropy is sometimes used. An example of polymorphism is titanium dioxide (TiO2), which occurs in four known natural polymorphic forms (minerals with the same composition but different structure): brookite (orthorhombic), akaogiite (monoclinic), anatase (tetragonal) and rutile (tetragonal). Eilhard Mitscherlich discovered polymorphism ("dimorphism") in his studies of sodium phosphate (1821) and sulphur (1823). In the 1830s the development of the microscope enhanced observations of polymorphism and aided Moritz Ludwig Frankenheim's studies. Frankenheim was able to demonstrate methods to induce crystal phase changes, for example the use of solvents or physical scratching, and formally summarized his findings on the nature of polymorphism. Soon after, the more sophisticated polarized light microscope came into use, and it provided better visualization of crystalline phases allowing crystallographers to distinguish between different polymorphs. The hot stage was invented and fitted to a polarized light microscope by Otto Lehmann in about 1877. This invention helped crystallographers determine melting points and observe polymorphic transitions. The first polymorphic organic substance, benzamide, was discovered by Friedrich Wöhler and Justus von Liebig in 1832. In 1870 Paul Groth defined wikt:morphotropy as the state of two crystals whose similar physical structure is due to similar chemical composition.
In 1959 Ernst Freese coined the terms "transitions" or "transversions" to categorize different types of point mutations. Transitions are replacement of a purine base with another purine or replacement of a pyrimidine with another pyrimidine. Transversions are replacement of a purine with a pyrimidine or vice versa. There is a systematic difference in mutation rates for transitions (Alpha) and transversions (Beta). Transition mutations are about ten times more common than transversions.
Sources: en.wikipedia.org
=== Coupled folding and binding === Many unstructured proteins undergo transitions to ordered states upon binding to their targets (e.g. molecular recognition features (MoRFs)). The coupled folding and binding may be local, involving only a few interacting residues, or it might involve an entire protein domain. It was recently shown that the coupled folding and binding allows the burial of a large surface area that would be possible only for fully structured proteins if they were much larger. Moreover, certain disordered regions might serve as "molecular switches" in regulating certain biological function by switching to ordered conformation upon molecular recognition like small molecule-binding, DNA/RNA binding, ion interactions etc. The ability of disordered proteins to bind, and thus to exert a function, shows that stability is not a required condition. Many short functional sites, for example short linear motifs are over-represented in disordered proteins. Disordered proteins and short linear motifs are particularly abundant in many RNA viruses such as Hendra virus, HCV, HIV-1 and human papillomaviruses. This enables such viruses to overcome their informationally limited genomes by facilitating binding, and manipulation of, a large number of host cell proteins.
But being doomed seldom sounded so beautiful." AllMusic's Heather Phares viewed III as the duo's "most serious set of songs yet" and stated, "Artistic progress is as much about subtraction as it is about addition, and on III, Crystal Castles have made room to be sad, angry, pretty, and danceable at the same time." Pitchfork's Ian Cohen dubbed III "the duo's most focused record", adding, "While not as immediately striking as either Crystal Castles (I or II), the streamlined sound allows more maneuverability and subtle variety in the actual songwriting." Matt James of PopMatters wrote, "Perennial outsiders to the death, Crystal Castles' third act is inspiring, warped, feverishly uncomfortable, bold, bloody and brilliant." Dan Pfleegor of Consequence of Sound opined that "III is less playful than the duo's previous couple of offerings, but its thematic mood is much tighter and more fully realized." The Guardian's Tim Jonze noted that "witch house is an obvious influence [on the album], and you could question whether the former chip-tune terrorists are still as ahead of the curve as they once were. It hardly matters when they can come up with stuff like 'Child I Will Hurt You', a dream-state lullaby that is both beautiful and unbearably sorrowful." Simon Price of The Independent stated that the album "shudders and shimmers like some massive, monstrous machine.
=== Enhanced 25 mm gun === Work on an upgraded weapon began in 1990. In the upgrade program, all three major systems and seven minor systems were improved. The modifications began with introducing a chrome-lined barrel, an enhanced feeder, and an enhanced receiver. The weapon systems also received minor upgrades such as quick-detachable link covers, a larger breech assembly, a high efficiency muzzle brake, longer recoil, an integral round counter, an extended life firing pin and spring, and a triple-spring drive clutch. Upgraded weapons were first put to use on the M2A3 Bradley, the fourth version of the M2 Bradley fighting vehicle.
Small, medium, and large veins The small veins merge to feed as tributaries into medium-sized veins. The medium veins feed into the large veins which include the internal jugular, and renal veins, and the venae cavae that carry the blood directly into the heart. The venae cavae enter the right atrium of the heart from above and below. From above, the superior vena cava carries blood from the arms, head, and chest to the right atrium of the heart, and from below, the inferior vena cava carries blood from the legs and abdomen to the right atrium. The inferior vena cava is the larger of the two. The inferior vena cava is retroperitoneal and runs to the right and roughly parallel to the abdominal aorta along the spine.
== Mitochondria == ATP can be generated by substrate-level phosphorylation in mitochondria in a pathway that is independent from the proton motive force. In the matrix there are three reactions capable of substrate-level phosphorylation, utilizing either phosphoenolpyruvate carboxykinase or succinate-CoA ligase, or monofunctional C1-tetrahydrofolate synthase.
Sources: en.wikipedia.org
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.
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.
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.
不存在。它是依据 ACTH 的一段序列人工设计的分子，天然蛋白质中找不到与之完全相同的七肽。名称属于研究代号，而非天然物质名。