The short version of Semax fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-01-06 and is reviewed periodically as new material appears.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It is described in the literature as an analogue of the ACTH(4–10) fragment, a short N-terminal portion of adrenocorticotropic hormone that retains some neurotropic activity without the full hormonal effects of the parent peptide. The molecule carries a methionine residue at the N-terminus and two proline residues near the C-terminus, features that shape both its interactions with receptor systems and its chemical stability. The free peptide corresponds to the formula C37H51N9O10S and a molecular mass near 813.9 Da.
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.
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.
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.
| 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 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.
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.
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。
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。
== Corneal nerves == Corneal nerves serve as a form of defense by detecting the presence of foreign bodies on the corneal surface. This leads to reflexive reactions such as increased lacrimal secretion, blinking, and release of neuropeptides, which can induce cytokine activation.
In 2016, the breakdown of a 20-year truce between the PCC and the Red Command (CV) led to a massive uptick in violence across Brazil, with the PCC embarking on an aggressive expansion campaign by absorbing less organized gangs and financing local groups to operate as proxies against the CV across the country, such as the B13 gang in Acre and the CV's rivals in Rio de Janeiro. Between 2016 and 2020, a series of gruesome prison riots made headlines worldwide as the PCC fought for control of the North Region against the Família do Norte, allies with the Comando Vermelho. On January 1, dozens of PCC prisoners were massacred at the Anísio Jobim Penitentiary Complex in Manaus after a prison riot, with the PCC retaliating in prison riots in Boa Vista and in Natal in the same week. Dismemberments, beheadings and prisoners being burned alive were commonplace during all three prison riots. Between 2015 and 2018, the Familia do Norte and the Comando Vermelho (CV) formed an alliance to prevent the advance of the Primeiro Comando da Capital (PCC) in Amazonas. In 2018, the alliance dissolved, generating a confrontation between the CV and Familia do Norte, weakening the faction. 33 prisoners were killed in the Agricultural Penitentiary of Monte Cristo riot, located in the rural area of Boa Vista, Roraima, also in the North. According to Folha de S.Paulo, the massacre in Roraima was a response of the PCC to the rebellion commanded by the FDN in the Amazon. Even more people were killed later on in the month. More than 106 were the fatalities during those prison riots.
For the rational design of new complexes the concept of the isolobal analogy has been found useful. Roald Hoffmann was awarded the Nobel Prize in chemistry for the development of the concept. This describes metal carbonyl fragments of M(CO)n as parts of octahedral building blocks in analogy to the tetrahedral CH3–, CH2– or CH– fragments in organic chemistry. In example dimanganese decacarbonyl is formed in terms of the isolobal analogy of two d7 Mn(CO)5 fragments, that are isolobal to the methyl radical CH•3. In analogy to how methyl radicals combine to form ethane, these can combine to dimanganese decacarbonyl. The presence of isolobal analog fragments does not mean that the desired structures can be synthesized. In his Nobel Prize lecture Hoffmann emphasized that the isolobal analogy is a useful but simple model, and in some cases does not lead to success. The economic benefits of metal-catalysed carbonylations, such as Reppe chemistry and hydroformylation, led to growth of the area. Metal carbonyl compounds were discovered in the active sites of three naturally occurring enzymes.
Sources: en.wikipedia.org
Subsequent research suggests that multiple waves of immune cells develop through hematopoiesis from hemogenic endothelial cells (ECs), independent of HSCs, with HSCs arising in a later hematopoietic wave. Tissue-resident immune cells may be either fetal-derived or the progeny of adult HSCs. In vertebrates, the earliest source of mast cells is the extraembryonic yolk sac, where blood and immune cells first develop. However, there are differences in the embryonic development of vertebrates such as mice compared to primates (including humans). In primates, yolk sac formation involves a transient primary yolk sac, and the formation of extraembryonic mesoderm, prior to generation of a secondary yolk sac where the first blood cells of the embryo develop. During embryonic development, mast cell progenitors (MCps) form in a series of developmentally discrete waves. The first wave of mast cells in the embryo is derived from erythro-myeloid progenitors (EMPs) in the yolk sac, before hematopoietic stem cells (HSC) emerge. In mouse models, the earliest mast cell progenitors originate in the embryo around embryonic day 7 (E7.5-E8.5). Transient erythro-myeloid progenitors (EMPs) develop in the yolk sac between E8.5-E10.5 and in fetal liver (FL) between E11.5-E13.5. Embryonic multipotent progenitors (eMPPs) and hematopoietic stem cells (HSCs) emerge around E10.5. Mast cell differentiation in the fetal liver (FL) starts from E11, along with a peak in the number of mast cell progenitors.
== Arts and media == Cariyapitaka (Cp), a canonical Buddhist story collection The Canadian Press, a Canadian news agency Cartoon Planet, Cartoon Network television programming block Cartoon pornography Child pornography The Christian Post, an American newspaper Competitive programming Club Penguin, a now defunct online multiplayer game Combat power, used in Pokémon Go to indicate how strong a Pokémon is in battle
=== Role in cancer === ABCC1 plays a role in the multidrug resistance of cancerous tumor cells due to its ability to transport many chemotherapeutic drugs out of the cells. The ABCC1 transporter protein is especially prevalent in neuroblastoma and cancer cells found in the lung, breast and prostate. In non-small cell lung carcinoma and small cell lung carcinoma, higher expression of ABCC1 was indicative of a reduced response to chemotherapeutic drugs and a lower rate of survival. Similar results were found in early-stage breast cancer where the increased expression of the transporter gene correlated with shorter times until a relapse occurred and lower rates of survival. In prostate cancer, expression of ABCC1 was found to increase with the stage of the disease while allowing resistance to chemotherapeutic drugs.
Sources: en.wikipedia.org
Astatine is a chemical element; it has symbol At and atomic number 85. It is the rarest naturally occurring element in the Earth's crust, occurring only as the decay product of various heavier elements. All of astatine's isotopes are short-lived; the most stable is astatine-210, with a half-life of 8.1 hours. Consequently, a solid sample of the element has never been seen, because any macroscopic specimen would be immediately vaporized by the heat of its radioactivity. The bulk properties of astatine are not known with certainty. Many of them have been estimated from its position on the periodic table as a heavier analog of fluorine, chlorine, bromine, and iodine, the four stable halogens. However, astatine also falls roughly along the dividing line between metals and nonmetals, and some metallic behavior has also been observed and predicted for it. Astatine is likely to have a dark or lustrous appearance and may be a semiconductor or possibly a metal. Chemically, several anionic species of astatine are known and most of its compounds resemble those of iodine, but it also sometimes displays metallic characteristics and shows some similarities to silver. The first synthesis of astatine was in 1940 by Dale R. Corson, Kenneth Ross MacKenzie, and Emilio G. Segrè at the University of California, Berkeley. They named it from the Ancient Greek ástatos (ἄστατος) 'unstable'. Four isotopes of astatine were subsequently found to be naturally occurring, although much less than one gram is present at any given time in the Earth's crust.
=== Bottom-up approach === This approach involves creating new biological systems in vitro by bringing together 'non-living' biomolecular components, often with the aim of constructing an artificial cell. Reproduction, replication, and assembly are three crucial self-organizational principles that are taken into account in order to accomplish this. Cells, which are made up of a container and a metabolism, are considered "hardware" in the definition of reproduction, whereas replication occurs when a system duplicates a perfect copy of itself, as in the case of DNA, which is considered "software." When vesicles or containers (such as Oparin's coacervates) formed of tiny droplets of molecules that are organic like lipids or liposomes, membrane-like structures comprising phospholipids, aggregate, assembly occur. The study of protocells exists along with other in vitro synthetic biology initiatives that seek to produce minimal cells, metabolic pathways, or "never-born proteins" as well as to mimic physiological functions including cell division and growth. Recently a cell-free system capable of self-sustaining using CO2 was engineered by bottom-up integrating metabolism with gene expression.
over a longer period of evolutionary time. Each amino acid is more or less likely to mutate into various other amino acids. For instance, a hydrophilic residue such as arginine is more likely to be replaced by another hydrophilic residue such as glutamine, than it is to be mutated into a hydrophobic residue such as leucine. (Here, a residue refers to an amino acid stripped of a hydrogen and/or a hydroxyl group and inserted in the polymeric chain of a protein.) This is primarily due to redundancy in the genetic code, which translates similar codons into similar amino acids. Furthermore, mutating an amino acid to a residue with significantly different properties could affect the folding and/or activity of the protein. This type of disruptive substitution is likely to be removed from populations by the action of purifying selection because the substitution has a higher likelihood of rendering a protein nonfunctional. If we have two amino acid sequences in front of us, we should be able to say something about how likely they are to be derived from a common ancestor, or homologous. If we can line up the two sequences using a sequence alignment algorithm such that the mutations required to transform a hypothetical ancestor sequence into both of the current sequences would be evolutionarily plausible, then we'd like to assign a high score to the comparison of the sequences. To this end, we will construct a 20x20 matrix where the
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.
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.