If you have been reading about semax and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2026-02-26. Where a claim depends on a specific study, the study is described rather than over-claimed.
The compound was developed in the 1980s at the Institute of Molecular Genetics in Moscow, where it emerged from research on short ACTH fragments and their effects on the central nervous system. Russian pharmaceutical listings describe it as a nootropic and neuroprotective agent, most often formulated as nasal drops. It is not a marketed medicine in the United States or the European Union, and no pharmacopoeial monograph covers it. Consequently, most published clinical experience with the substance originates from a small number of research centres, mainly in Russia and neighbouring countries.
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.
The mechanisms attributed to semax are inferred from animal and cell studies rather than traced to one confirmed target. The most frequently cited pathway involves increased expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal and cortical tissue. Some work points to engagement of melanocortin receptors, particularly MC4, which the parent ACTH fragment can activate. Effects on dopaminergic and serotonergic signalling have also been reported. No single account explains all observed results, and the relative weight of each pathway remains unsettled.
Published studies examine a fairly narrow set of endpoints. Rodent experiments commonly measure maze learning, infarct volume after induced ischemia, and tissue levels of neurotrophic factors. Clinical reports from Russian centres describe attention, memory and recovery scores in patients after stroke or transient ischemic attack. Most of those human studies are small and few have been repeated by independent groups. Outcome measures differ between studies, which limits direct comparison.
Circulation time for the peptide is short because peptidases cleave it readily. The Pro-Gly-Pro tail is thought to slow breakdown compared with the bare ACTH fragment, but the gain appears modest. Absorption after intranasal dosing is limited, and only a fraction of a dose is expected to reach the central nervous system. Laboratory concentrations therefore sit well above levels achieved systemically, a gap that complicates translation from bench findings to clinical claims.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Free acid form of the heptapeptide; depends on terminal groups |
| Molecular mass | About 813.9 g/mol | Average mass used for mass spectrometry confirmation |
| Appearance | White to off-white solid | Supplied as a lyophilised powder; hygroscopic |
| Solubility class | Freely soluble in aqueous media | Water, saline, and phosphate buffers; limited organic solubility |
| Typical storage temperature | -20 degrees Celsius | Long term and dry; short working periods may use 2 to 8 degrees Celsius |
Semax 是一种人工合成的七肽，氨基酸序列为 Met-Glu-His-Phe-Pro-Gly-Pro，单字母缩写记作 MEHFPGP。它被归类为促肾上腺皮质激素片段 ACTH(4-10) 的结构类似物，但并不天然存在于生物体内。母体片段 ACTH(4-10) 的序列为 Met-Glu-His-Phe-Arg-Trp-Gly，Semax 替换了中间两个残基，并在羧基端延长了 Pro-Gly-Pro 三肽。这种延长被普遍认为能提升分子对肽酶的耐受性。
该化合物于二十世纪八十年代在俄罗斯被开发，相关工作由俄罗斯科学院分子遗传学研究所的研究团队主导。开发目标并非复制 ACTH 的完整激素活性，而是寻找保留其神经作用方向、同时去除促肾上腺皮质激素释放效应的短肽片段。研究记录显示，这一方向促成了多个相关短肽的合成与筛选，而 Semax 是其中被研究最广泛的一个。当地文献常以 Семакс 这一名称指代它。
研究兴趣主要集中在神经营养因子相关的路径上，包括脑源性神经营养因子与神经生长因子的表达变化。部分实验报告称在特定条件下观察到这些因子的水平上升，但具体信号通路和剂量依赖关系仍未完全厘清。多数公开数据来自细胞模型和动物实验，人体对照研究数量有限。因此，该化合物的作用机制在文献中属于活跃讨论，而非已经确立的定论。
Identity and purity of semax are established with reversed-phase high-performance liquid chromatography coupled to ultraviolet detection, usually at 214 nanometres. Mass spectrometry, most often electrospray ionisation in positive mode, confirms the molecular mass and reveals truncated sequences. Amino acid analysis and peptide mapping after enzymatic digestion provide additional structural confirmation. Laboratories typically report purity as the percentage area of the main peak, a figure that does not capture isomeric or oxidised variants unless the method resolves them.
The peptide is prone to several degradation pathways. Oxidation of the methionine residue produces a sulfoxide that elutes close to the parent peak in many chromatographic systems. Hydrolysis of peptide bonds and deamidation of susceptible residues in related sequences also reduce purity over time. Lyophilised material kept dry at minus twenty degrees Celsius and shielded from light is the most stable form commonly described in laboratory practice.
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。
=== von Reumont et al. (2012) === In a 2012 molecular study, von Reumont et al. challenge the monophyly of Vericrustacea: they present four versions of Pancrustacea cladogram (figures 1–4), and in all four figures Remipedia is a sister group to Hexapoda, and Branchiopoda is a sister group to (Remipedia + Hexapoda). Thus, their data strongly suggest that Branchiopoda is more closely related to Hexapoda and Remipedia than to Multicrustacea. Based on these data, they propose the following scenario of evolution of Branchiopoda, Remipedia and Hexapoda: under the impact of predatory fishes their common ancestors go to the littoral zone, then ancestors of Branchiopoda go to the ephemeral freshwater habitat, whereas ancestors of Remipedia go to the anchialine cave, and ancestors of Hexapoda go to the land.
==== Effects on liver protein synthesis ==== A study compared the combination of 5 mg estradiol cypionate and 25 mg medroxyprogesterone acetate as a combined injectable contraceptive (which has been associated with peak estradiol levels of around 300 pg/mL) with an ethinylestradiol-containing combined birth control pill and found that whereas the birth control pill produced significant changes in coagulation parameters, there were no significant prothrombotic effects of the combined injectable contraceptive on levels of fibrinogen, factors VII and X, plasminogen, or the activated prothrombin time. As such, it appears that similarly to depot medroxyprogesterone acetate, combined injectable contraceptives with 5 mg estradiol cypionate and 25 mg medroxyprogesterone acetate have less or no procoagulant effect relative to combined birth control pills.
BC Research Inc. is a privately owned Canadian process technology incubator, specializing in custom research, process development and technology commercialization. Headquartered in Vancouver, British Columbia, BC Research operates primarily from their Technology Commercialization and Innovation Centre on Mitchell Island in the Vancouver suburb of Richmond. This 40,000 sq-ft facility includes a 28,000 sq-ft pilot plant development area, 2,500 sq-ft laboratory space, 9,000 sq-ft of office space, as well as a small machine shop and fenced outdoor piloting space. Technologies are scaled up from concept to pilot or demonstration scale in preparation for commercialization. Engineering support is provided by sister companies NORAM Engineering and Constructors Ltd. Previously, BC Research was located at the BC Research and Innovation Complex at the south end of the University of British Columbia campus. This facility closed in November 2007. The company specialized in consulting and applied research and development in the area of plant biotechnology and environment, health and safety, process and analysis, transportation and ship dynamics.
Sources: en.wikipedia.org
Optical storage uses lasers to store and retrieve data. Recordable CDs, DVDs, and Blu-ray Discs are commonly used with personal computers and are generally cheap. The capacities and speeds of these discs have typically been lower than hard disks or tapes. Advances in optical media may shrink that gap in the future. Potential future data losses caused by gradual media degradation can be predicted by measuring the rate of correctable minor data errors, of which consecutively too many increase the risk of uncorrectable sectors. Support for error scanning varies among optical drive vendors. Many optical disc formats are WORM type, which makes them useful for archival purposes since the data cannot be changed in any way, including by user error and by malware such as ransomware. Moreover, optical discs are not vulnerable to head crashes, magnetism, imminent water ingress or power surges; and, a fault of the drive typically just halts the spinning. Optical media is modular; the storage controller is not tied to media itself like with hard drives or flash storage (→flash memory controller), allowing it to be removed and accessed through a different drive. However, recordable media may degrade earlier under long-term exposure to light. Some optical storage systems allow for cataloged data backups without human contact with the discs, allowing for longer data integrity. A French study in 2008 indicated that the lifespan of typically-sold CD-Rs was 2–10 years, but one manufacturer later estimated the longevity of its CD-Rs with a gold-sputtered layer to be as high as 100 years.
In most eukaryotes, GSA is synthesised from the amino acid glutamate by the bifunctional enzyme 1-pyrroline-5-carboxylate synthase (P5CS). The human P5CS is encoded by the ALDH18A1 gene. The enzyme pyrroline-5-carboxylate reductase converts L-P5C into proline.
EF-G has a complex evolutionary history, with numerous paralogous versions of the factor present in bacteria, suggesting subfunctionalization of different EF-G variants. Elongation factors exist in all three domains of life with similar function on the ribosome. The eukaryotic and archeal homologs of EF-G are eEF2 and aEF2, respectively. In bacteria (and some archaea), the fusA gene that encodes EF-G is found within the conserved str gene with the sequence 5′ - rpsL - rpsG - fusA - tufA - 3′. However, two other major forms of EF-G exist in some species of Spirochaetota, Planctomycetota, and δ-Proteobacteria (which has since been split and renamed Bdellovibrionota, Myxococcota, and Thermodesulfobacteriota), which form the spd group of bacteria that have elongation factors spdEFG1 and spdEFG2. From spdEFG1 and spdEFG2 evolved the mitochondrial elongation factors mtEFG1 (GFM1) and mtEFG2 (GFM2), respectively. The two roles of EF-G in elongation and termination of protein translation are split amongst the mitochondrial elongation factors, with mtEFG1 responsible for translocation and mtEFG2 responsible for termination and ribosomal recycling with mitochondrial RRF.
Sources: en.wikipedia.org
It is described as a synthetic analogue of the ACTH(4–10) fragment, a short segment of adrenocorticotropic hormone. Its sequence differs from that fragment and includes two proline residues, which influence stability and behaviour in solution.
It appears in Russian pharmaceutical listings as a nasal formulation, but it is not an authorised medicine in the United States or the European Union. Outside those markets it is normally encountered as a research chemical rather than a prescription product.
Laboratory and animal work points to melanocortin signalling and changes in neurotrophic factor levels, especially brain-derived neurotrophic factor. The exact receptor targets and the degree to which these findings transfer to humans are still unresolved.
It consists mainly of animal experiments and small clinical reports, with much of the clinical material published in Russian-language journals. Large independent trials are scarce. Separating reliable effects from chance findings is consequently difficult.