semax is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Last reviewed on 2026-08-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
Routine characterization relies on reversed-phase high-performance liquid chromatography to establish purity and on mass spectrometry to confirm molecular identity. Electrospray ionization and matrix-assisted laser desorption ionization are both used for mass verification. Amino acid analysis and peptide mapping can detect sequence errors. Common impurities include truncated sequences, methionine sulfoxide formed by oxidation, and deamidated products. Chromatograms are usually recorded near 214 nm, where the peptide backbone absorbs, and purity is reported as the percentage area of the principal peak.
Verification of a supplied batch generally combines a certificate of analysis with independent testing, because certificates are self-reported documents. A typical package includes a chromatographic trace, a mass spectrum, and a stated water or counter-ion content. Batch-to-batch consistency matters more than a single purity figure when results are compared across experiments. No single mandatory standard governs research-grade peptide release, so laboratories are expected to define their own acceptance criteria. Residual trifluoroacetate from purification is a frequently overlooked counter-ion.
Lyophilized material is chemically stable for extended periods when kept dry, cold, and protected from light. The powder is hygroscopic, so vials should be warmed to room temperature before opening to reduce condensation on the contents. Once dissolved, the peptide is far less stable because peptide bonds are susceptible to hydrolysis and the methionine residue can oxidize. Solutions are typically aliquoted and held at 2-8 °C for short intervals or frozen for longer ones, and repeated freeze-thaw cycles should be avoided.
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.
| Property | Value | Notes |
|---|---|---|
| Typical purity | 95% or higher | By reversed-phase HPLC area |
| Identity method | Electrospray mass spectrometry | Confirms molecular mass |
| Purity method | Reversed-phase HPLC | Detection near 214 nm |
| Primary degradation | Methionine oxidation | Sulfoxide product, +16 Da |
| Solution storage | 2-8 °C, short term | Aliquot to avoid freeze-thaw |
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.
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.
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.
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.
从分子层面看，Semax 是线性七肽，没有二硫键、糖基或脂链修饰，N 端为游离氨基，C 端为游离羧基。分子含组氨酸与谷氨酸侧链，因此在水和甲醇等极性溶剂中溶解良好，在非极性溶剂中溶解有限。计算分子量约为 814 Da，与其质子化离子的质荷比吻合，可用于质谱确认。
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。
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。
Delta 6 desaturase is an enzyme involved in converting essential fatty acids to arachidonic acid and prostaglandins, both of which are important to the functioning of cells. Infertility in women: One 2007 study found, "Each 2% increase in the intake of energy from trans unsaturated fats, as opposed to that from carbohydrates, was associated with a 73% greater risk of ovulatory infertility...". Major depressive disorder: Spanish researchers analysed the diets of 12,059 people over six years and found that those who ate the most trans fats had a 48 per cent higher risk of depression than those who did not eat trans fats. One mechanism may be trans-fats' substitution for docosahexaenoic acid (DHA) levels in the orbitofrontal cortex (OFC). Very high intake of trans-fatty acids (43% of total fat) in mice from 2 to 16 months of age was associated with lowered DHA levels in the brain (p=0.001). When the brains of 15 major depressive subjects who had committed suicide were examined post-mortem and compared against 27 age-matched controls, the suicidal brains were found to have 16% less (male average) to 32% less (female average) DHA in the OFC. The OFC controls reward, reward expectation, and empathy (all of which are reduced in depressive mood disorders) and regulates the limbic system. Behavioral irritability and aggression: a 2012 observational analysis of subjects of an earlier study found a strong relation between dietary trans fat acids and self-reported behavioral aggression and irritability, suggesting but not establishing causality.
=== 11 August === At least 40 people were killed in an RSF attack on Abu Shouk camp. The SAF claimed to have killed more than 200 RSF fighters and destroyed or captured 46 combat vehicles following an RSF attack on El Fasher. Nine people were abducted by the RSF during the event.
=== Wound healing and fibrosis === In skin wound healing, CCN1 is highly expressed in the granulation tissue by myofibroblasts, which proliferate and rapidly synthesize ECM to maintain tissue integrity and to promote regeneration of parenchymal cells. However, excessive matrix deposition can lead to fibrosis, scarring, and loss of tissue function. In skin wounds, CCN1 accumulates in the granulation tissue as myofibroblasts proliferate, and eventually reaches a sufficiently high level to drive the myofibroblasts themselves into senescence, whereupon these cells cease to proliferate and express matrix-degrading enzymes. Thus, CCN1 limits synthesis and deposition of ECM by myofibroblasts, reducing the risk of fibrosis during wound healing. In addition to skin wound healing, CCN1 expression is elevated in remodeling cardiomyocytes after myocardial infarction, in vascular injury, and in the long bones during fracture repair. Blockade of CCN1 by antibodies inhibits bone fracture healing in mice. In the kidney, CCN1 is expressed in podocytes in normal adult and embryonic glomeruli, but expression is decreased in IgA nephropathy, diabetic nephropathy, and membranous nephropathy, particularly in diseased kidneys with severe mesangial expansion. CYR61 induction of cellular senescence in the kidney is a potential therapy to limit fibrosis.
Before 2011, India had prevented innovation and organised competition in its consumer retail industry. Several studies claim that the lack of infrastructure and competitive retail industry is a key cause of India's persistently high inflation. Furthermore, because of unorganised retail, in a nation where malnutrition remains a serious problem, food wastage is rife. Well over 30% of food staples and perishable goods produced in India spoil because of poor infrastructure and small retail outlets prevent hygienic storage and movement of the goods from the farmer to the consumer. One report estimates the 2011 Indian retail market as generating sales of about $470 billion a year, of which a minuscule $27 billion comes from organised retail such as supermarkets, chain stores with centralised operations and shops in malls. The opening of retail industry to free market competition, some claim will enable rapid growth in retail sector of Indian economy. Others believe the growth of Indian retail industry will take time, with organised retail possibly needing a decade to grow to a 25% share. A 25% market share, given the expected growth of Indian retail industry through 2021, is estimated to be over $250 billion a year: a revenue equal to the 2009 revenue share from Japan for the world's 250 largest retailers., The Economist forecasts that Indian retail will nearly double in economic value, expanding by about $850 billion by 2020. The projected increase alone is equivalent to the current retail market size of France.
== Applications of freeze cast materials == Freeze casting is unique in its ability to produce aligned pore structures. Such structures are often found in nature, and consequently freeze casting has emerged as a valuable tool to fabricate biomimetic structures. The transport of fluids through aligned pores has led to the use of freeze casting as a method towards biomedical applications including bone scaffold materials. The alignment of pores in freeze cast structures also imparts extraordinarily high thermal resistance in the direction perpendicular to the aligned pores. The freeze casting of aligned porous fibres by spinning processes presents a promising method towards the fabrication of high performance insulating clothing articles. In addition, materials with aligned pores produced via freeze casting from sintered nickel powder have gained significant attention in phase-change systems, such as loop heat pipes (LHPs), due to their excellent thermal properties. In these systems, wicks play a critical role in maintaining liquid-vapor equilibrium, enabling efficient circulation of the working fluid. Traditional wicks are often manufactured separately and integrated later, creating an interface that limits liquid transfer efficiency. To address this limitation, a porous wick with a gradient structure was developed in a single operation using freeze casting. This innovative approach eliminates interfacial resistance, ensuring seamless liquid transport while maintaining the high thermal conductivity and efficient capillary action required for optimal LHP performance.
Sources: en.wikipedia.org
FMN + NAD(P)H + H+ The 3 substrates of this enzyme are FMNH2, NAD+, and NADP+, whereas its 4 products are FMN, NADH, NADPH, and H+. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-NH group of donors with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is FMNH2:NAD(P)+ oxidoreductase. Other names in common use include NAD(P)H-FMN reductase, NAD(P)H-dependent FMN reductase, NAD(P)H:FMN oxidoreductase, NAD(P)H:flavin oxidoreductase, NAD(P)H2 dehydrogenase (FMN), NAD(P)H2:FMN oxidoreductase, SsuE, riboflavin mononucleotide reductase, flavine mononucleotide reductase, riboflavin mononucleotide (reduced nicotinamide adenine dinucleotide, (phosphate)) reductase, flavin mononucleotide reductase, and riboflavine mononucleotide reductase.
=== Xander Lindt === Xander Lindt (Gustav Lindh) is a cocky young heir of the Lindt chocolate empire, and a member of Henry's entourage. He repeatedly demeans Yasmin after she rejects his sexual advances at a Swiss climate conference.
==== Cholesterol synthesis ==== The cytosolic acetyl-CoA can also condense with acetoacetyl-CoA to form 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) which is the rate-limiting step controlling the synthesis of cholesterol. Cholesterol can be used as is, as a structural component of cellular membranes, or it can be used to synthesize steroid hormones, bile salts, and vitamin D.
== Side effects == Protriptyline shares side effects common to all TCAs. The most frequent of these are dry mouth, constipation, urinary retention, increased heart rate, sedation, irritability, decreased coordination, anxiety, blood disorders, confusion, decreased libido, dizziness, flushing, headache, impotence, insomnia, low blood pressure, nightmares, rapid or irregular heartbeat, rash, seizures, sensitivity to sunlight, stomach and intestinal problems. Other more complicated side effects include; chest pain or heavy feeling, pain spreading to the arm or shoulder, nausea, sweating, general ill feeling; sudden numbness or weakness, especially on one side of the body; sudden headache, confusion, problems with vision, speech, or balance; hallucinations, or seizure (convulsions); easy bruising or bleeding, unusual weakness; restless muscle movements in your eyes, tongue, jaw, or neck; urinating less than usual or not at all; extreme thirst with headache, nausea, vomiting, and weakness; or feeling light-headed or fainting. Dry mouth, if severe to the point of causing difficulty speaking or swallowing, may be managed by dosage reduction or temporary discontinuation of the drug. Patients may also chew sugarless gum or suck on sugarless candy in order to increase the flow of saliva. Some artificial saliva products may give temporary relief. Men with prostate enlargement who take protriptyline may be especially likely to have problems with urinary retention. Symptoms include having difficulty starting a urine flow and more difficulty than usual passing urine.
A primordial element is a chemical element with at least one primordial nuclide. There are 251 stable primordial nuclides and 35 radioactive primordial nuclides, but only 80 primordial stable elements—hydrogen through lead, atomic numbers 1 to 82, except for technetium (43) and promethium (61)—and three radioactive primordial elements—bismuth (83), thorium (90), and uranium (92). If plutonium (94) turns out to be primordial (specifically, the long-lived isotope 244Pu), then it would be a fourth radioactive primordial, though practically speaking it would still be more convenient to produce synthetically. Bismuth's half-life is so long that it is often classed with the 80 stable elements instead, since its radioactivity is not a cause for concern. The number of elements is smaller than the number of nuclides, because many of the primordial elements are represented by multiple isotopes. See chemical element for more information.
Sources: en.wikipedia.org
Dry powder is normally held at -20 °C or lower, away from light and moisture. Sealed vials can also be kept at 2-8 °C for shorter intervals. Warming to room temperature before opening prevents condensation.
In solution, hydrolysis of peptide bonds and oxidation of the methionine residue are the principal concerns. Oxidation converts methionine to its sulfoxide form, shifting the mass by sixteen daltons. Both processes are slowed by cold storage and by avoiding alkaline conditions.
A certificate documents what the supplier measured on a specific lot, not how a laboratory will use the material. Independent verification of identity and purity is common practice. Acceptance criteria should be defined before a batch is ordered.
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.