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 2025-10-17 and is reviewed periodically as new material appears.
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.
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.
The proposed mechanism centres on neurotrophic signalling rather than direct receptor activation. Semax is reported to increase expression of brain-derived neurotrophic factor and nerve growth factor in several brain regions, and to shift the balance between excitatory and inhibitory neurotransmitter systems. Interaction with melanocortin receptors has been suggested because of the parent ACTH fragment. Many of these findings come from rodent studies, and the extent to which they translate to human physiology remains an open question.
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.
| 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 |
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。
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。
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.
===== Type 2N (Normandy) ===== Type 2N VWD results from a loss-of-function mutation that reduces the binding of von Willebrand factor (VWF) to factor VIII. Although VWF antigen (quantity) and activity levels (Ristocetin cofactor assay) remain normal, factor VIII levels are typically low (usually 5-15%) due to impaired VWF binding. This vulnerability to proteolysis in the circulation leads to clinical manifestations resembling those of Hemophilia A. The significantly reduced factor VIII levels in VWD Type 2N can sometimes lead to misdiagnosis as mild Hemophilia A. Like Hemophilia A, VWD Type 2N presents with joint and soft tissue bleeds. It is an autosomal recessive disorder, requiring either homozygosity or double heterozygosity for disease manifestation. Diagnostic tools include assessing the ratio of VWF binding to VWF antigen levels. A ratio <0.3 indicates homozygous or double heterozygous VWD Type 2N, while a ratio <0.5 suggests heterozygous VWD Type 2N. Conversely, a VWF antigen-to-binding ratio >3 confirms the diagnosis of VWD Type 2N. Ristocetin-Induced Platelet Agglutination (RIPA) and VWF multimer analysis are typically normal.
=== Cold fusion === 208Pb(48Ca,xn)256−xNo (x=1,2,3,4) This cold fusion reaction was first studied in 1979 at Flerov Laboratory of Nuclear Reactions (FLNR). Further work in 1988 at GSI measured EC and SF branchings in 254No. In 1989, the FLNR used the reaction to measure SF decay characteristics for the two isomers of 254No. The measurement of the 2n excitation function was reported in 2001 by Yuri Oganessian at the FLNR. Patin et al. at the LBNL reported in 2002 the synthesis of 255–251No in the 1-4n exit channels and measured further decay data for these isotopes. The reaction has recently been used at Jyväskylän Yliopisto Fysiikan Laitos (JYFL) using the RITU set-up to study K-isomerism in 254No. The scientists were able to measure two K-isomers with half-lives of 275 ms and 198 s, respectively. They were assigned to 8− and 16+ K-isomeric levels. The reaction was used in 2004–5 at the FLNR to study the spectroscopy of 255–253No. The team were able to confirm an isomeric level in 253No with a half-life of 43.5 s.
== Hybridization == Many species that share the same genus have been known to interbreed and create hybrids. Many species of crotalid rattlesnakes have been documented hybridizing in their natural habitats and in captivity. In southwestern New Mexico the Mojave rattlesnake is known to hybridize with the Prairie rattlesnake. These hybrids have been shown to have an overall lower body condition than either parent species. Experiments with hybrids between C. viridis and C. scutulatus have shown no advantage when it comes to hunting and the metrics are about the same across all species. The hybridization of rattlesnake species can also lead to a change in the overall venom toxicity and composition. This change can lead to a difficulty in treating bites. Rattlesnakes offer the best example for venom differences across the genus with many different species possessing different venom types. It is believed that hybridization is one of the leading causes for this variation in venom types and envenoming strategies.
In October 1928, Chiang Kai-shek appointed Liu Wenhui as Chairman of the Sichuan Provincial Government. Liu's inauguration occurred on 12 March 1929. He declared that he would focus on relieving the people's suffering and advancing their welfare.
Sources: en.wikipedia.org
Arthrodesis is used in horses as a salvage procedure to treat severe breakdown injuries, such as failure of the suspensory apparatus, subluxation, fracture, or collateral ligament rupture. It is also performed in horses with osteoarthritis, primarily of the distal hock joints, to fuse these low-motion joints so they no longer produce pain for the animal.
Following Charles Darwin's 1859 On the Origin of Species, Fuhlrott and Schaaffhausen argued that Neanderthal 1 represents a primitive lower human form, aligning more closely with non-human apes as well as Negroids, Eskimos, and Aboriginal Australians (which were variably classified as separate species or subspecies of human at the time). The binomial name Homo neanderthalensis was first proposed by William King in a paper read to the 33rd British Science Association in 1863, formally recognising it as distinct from modern humans. However, in 1864 he recommended that Neanderthals and modern humans be classified in different genera as he compared the Neanderthal braincase to that of a chimpanzee and argued that they were "incapable of moral and [theistic] conceptions". The uniqueness of Neanderthal Man met opposition namely from the pathologist Rudolf Virchow, who argued against defining new species based on only a single find. In 1872, Virchow erroneously interpreted Neanderthal characteristics as evidence of senility, disease, and malformation instead of archaicness, which stalled Neanderthal research until the end of the century. By the early 20th century, numerous other Neanderthal discoveries were made, establishing H. neanderthalensis as a legitimate species. At first, many palaeontologists considered Neanderthals to be an intermediary phase between modern humans and more apelike ancestors, as suggested by German anatomist Gustav Albert Schwalbe.
=== Genome === Chinese scientists published a draft genome of Ginkgo biloba in 2016. The tree has a large genome of 10.6 billion DNA nucleobase "letters" (the human genome has three billion) and about 41,840 predicted genes which enable a considerable number of antibacterial and chemical defense mechanisms. 76.58% of the assembled sequence turned out to be repetitive sequences. In 2020, a study in China of ginkgo trees up to 667 years old showed little effects of aging, finding that the trees continued to grow with age and displayed no genetic evidence of senescence, and continued to make phytochemicals indefinitely.
An MH mouse has been constructed, bearing the R163C mutation prevalent in humans. These mice display signs similar to human MH patients, including sensitivity to halothane (increased respiration, body temperature, and death). Blockade of RYR1 by dantrolene prevents adverse reaction to halothane in these mice, as with humans. Muscle from these mice also shows increased K+-induced depolarization and an increased caffeine sensitivity.
== History == On 18 January 1839, the British East India Company landed Royal Marines at Aden. Their aims were to establish a supply port and stop attacks by Arab pirates against British shipping to India. The British Government thereafter considered Aden to be an important settlement due to its location, as the Royal Navy could easily access the port for resupply and repairs. Later, British influence extended progressively into the hinterland, both west and east, leading to the establishment of the Aden Protectorate.
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.
Semax is based on the ACTH(4-10) fragment, a seven-amino-acid segment of adrenocorticotropic hormone. The synthetic peptide retains the core sequence while removing regions associated with endocrine activity. This modification is intended to isolate effects on the nervous system.