neurotrophic factor raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-03-26 and is reviewed periodically as new material appears.
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.
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 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。
Patrick Pierre Sabatier, La pomme de terre, c'est aussi un produit diététique, Robert Laffont, 1993, 275 p. (ISBN 2-221-07631-1). Racines, tubercules, plantains et bananes dans la nutrition humaine, FAP, coll. « Nutrition », no 24, Rome, 1991 (ISBN 92-5-202862-5). Joël Robuchon et Patrick Sabatier, Le Meilleur et le Plus Simple de la pomme de terre, Robert Laffont, 1994, 250 p. (ISBN 2-253-08159-0).
=== Treatment of alcoholism === Apomorphine was one of the earliest used pharmacotherapies for alcoholism. The Keeley Cure (1870s to 1900) contained apomorphine, among other ingredients, but the first medical reports of its use for more than pure emesis come from James Tompkins and Charles Douglas. Tompkins reported, after injection of 6.5 mg ("one tenth of a grain"):In four minutes free emesis followed, rigidity gave way to relaxation, excitement to somnolence, and without further medication the patient, who before had been wild and delirious, went off into a quiet sleep.Douglas saw two purposes for apomorphine:[it can be used to treat] a paroxysm of dipsomania [an episode of intense alcoholic craving]... in minute doses it is much more rapidly efficient in stilling the dipsomaniac craving than strychnine or atropine… Four or even 3m [minim – roughly 60 microlitres] of the solution usually checks for some hours the incessant demands of the patient… when he awakes from the apomorphine sleep he may still be demanding alcohol, though he is never then so insistent as before. Accordingly it may be necessary to repeat the dose, and even to continue to give it twice or three times a day. Such repeated doses, however, do not require to be so large: 4 or even 3m is usually sufficient.This use of small, continuous doses (1/30th of a grain, or 2.16 mg by Douglas) of apomorphine to reduce alcoholic craving comes some time before Pavlov's discovery and publication of the idea of the "conditioned reflex" in 1903.
Homeobox protein cut-like 1 is a protein that in humans is encoded by the CUX1 gene (previously CUTL1). This protein is a homeodomain protein. The term "cut" in the name "cut-like 1" derives from the "cut wing" phenotype observed in a mutant of Drosophila melanogaster. In mammals, a CCAAT-displacement activity was originally described in DNA binding assays. The human gene was identified following purification of the CCAAT-displacement protein (CDP) and has been successively been called CDP, Cut-like 1 (CUTL1), CDP/Cut and finally, CUX1. (Consequently, a literature search for CUX1 fails to bring up many of the earlier studies). Cut homeobox genes are present in all metazoans. In mammals, CUX1 is expressed ubiquitously in all tissues. A second gene, called CUX2, is expressed primarily in neuronal cells.
Sources: en.wikipedia.org
The most stable and dense form of selenium is gray and has a chiral hexagonal crystal lattice (space group 152 or 154 depending on the chirality) consisting of helical polymeric chains, where the Se–Se distance is 237.3 pm and Se–Se–Se angle is 103.1°. The minimum distance between chains is 343.6 pm. Gray selenium is formed by mild heating of other allotropes, by slow cooling of molten selenium, or by condensing selenium vapor just below the melting point. Whereas other selenium forms are insulators, gray selenium is a semiconductor showing appreciable photoconductivity. Unlike the other allotropes, it is insoluble in CSs. It resists oxidation by air and is not attacked by nonoxidizing acids. With strong reducing agents, it forms polyselenides. Selenium does not exhibit the changes in viscosity that sulfur undergoes when gradually heated.
== Editing and Proofreading == The specificity of the amino acid activation is as critical for the translational accuracy as the correct matching of the codon with the anticodon. The reason is that the ribosome only sees the anticodon of the tRNA during translation. Thus, the ribosome will not be able to discriminate between tRNAs with the same anticodon but linked to different amino acids. By attaching the correct amino acid to its associated tRNA molecule, activation ensures both specificity and fidelity of translation. Editing mechanisms occur when there is a misactivation of amino acids, where an amino acid is attached to the wrong tRNA molecule. The aminoacyl-tRNA synthetase can hydrolyze the amino acid before it attaches to the wrong tRNA molecule (pre-transfer editing) or deacylate the mischarged tRNA after attachment (post-transfer editing). The error frequency of the amino acid activation reaction is approximately 1 in 10,000 despite the small structural differences between some of the amino acids.
=== Australian refugee advertisement === In 2002, Nando's ran an advertising campaign in Australia based around a political controversy regarding the mandatory detention of refugees. The detainees had been waging a hunger strike campaign, even resorting to sewing their lips closed. Nando's adverts proclaimed that the strikers "decided to unsew their lips after hearing the news that with every Nando's quarter chicken combo, Nando's are giving away an extra quarter chicken free." Melbourne's Sphere Advertising said that the ad was designed to spark controversy, saying that they knew that "there's a section of our audience that's going to be uncomfortable... but we want to evoke a response."
Sources: en.wikipedia.org
=== Direct Chemical Synthesis === Although the focus has primarily been on enzymatic approaches for overcoming length limitations with oligonucleotide synthesis, a proposed alternative is direct chemical synthesis. Standard oligo-synthesis is done on porous materials, such as controlled pore glass (CPG). However, this environment introduces challenges as sequence length increases. Longer strands take up more space within the pores and limit reagent access, which results in lower coupling efficiency and a greater number of truncated sequences in a solution. One innovative approach includes chemically synthesizing the oligonucleotides on a smooth surface, as opposed to porous material, to improve coupling efficiency while additionally utilizing the purification strategy, catching-by-polymerization (CBP), to selectively isolate full-length oligos in a solution. Performing chemical synthesis on a smooth surface, such as glass wool or glass beads, reduces steric strain and congestion, thus providing alternative solid support benefitting long-oligos.
The flying primate hypothesis proposed that when adaptations to flight are removed, megabats are allied to primates and colugos by anatomical features not shared with microbats, and thus flight evolved twice in mammals. Genomic studies, however, have contradicted this hypothesis, strongly supporting the common ancestry of all bats and the single origin of mammal flight.
== Function == The alpha 3 type VI chain has been shown to bind extracellular matrix proteins, an interaction that explains the importance of this collagen in organizing matrix components. Microfibril formation has been traced to interactions between its N-terminal subdomain N5 and its C-terminal C5 domain in adjacent type VI collagen monomers.
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.