If you have been reading about single-use aliquot 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.
Updated 2026-05-03. Numbers and descriptions here follow the published literature rather than marketing material.
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.
Lyophilised powder is normally kept at -20 °C in a desiccated container, with some suppliers recommending -80 °C for long-term archival storage. Repeated freeze-thaw cycles are the most common cause of avoidable loss, so aliquoting before freezing reduces variability between working sessions. Dissolved peptide is far less stable than the dry solid and is usually prepared fresh or held briefly at 4 °C. Aqueous solutions support both hydrolysis of the backbone and oxidation of the N-terminal methionine, and these two routes dominate degradation under ordinary laboratory conditions.
Identity and purity are confirmed with reversed-phase high-performance liquid chromatography, typically monitored at 214 nanometres where the peptide bond absorbs. Mass spectrometry, either electrospray or MALDI-TOF, verifies molecular mass against the theoretical value and detects truncation or adduct formation. Amino acid analysis and peptide mapping provide additional confirmation when required. The most frequently reported impurities are deletion sequences from incomplete coupling, methionine sulfoxide from oxidation, and dimeric species formed through non-covalent aggregation. Impurity profiles depend strongly on the synthesis and purification route chosen by the producer.
Published research has focused mainly on neurological and cognitive endpoints in animal models, with proposed mechanisms involving brain-derived neurotrophic factor and related signalling pathways. A substantial share of the human data originates from a limited number of research groups, and independent replication in other countries remains sparse. Regulatory status reflects that distribution: the peptide is registered as a medicine in Russia and appears in some neighbouring markets, while elsewhere it is handled as a research chemical without approved therapeutic labelling. Questions about dose-response relationships, long-term effects, and comparability across studies are still open.
| 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. Its design combines the ACTH(4-7) core fragment with a C-terminal Pro-Gly-Pro extension, a modification intended to improve stability and prolong activity. The molecule is hydrophilic, carries no lipid chains or glycosylation, and has a theoretical mass just over 810 daltons in its free form. All seven residues are proteinogenic amino acids, so no non-natural building blocks appear in the backbone. A free N-terminal methionine and C-terminal proline define the unmodified parent peptide.
The compound was developed during the 1980s at the Institute of Molecular Genetics in Moscow as part of research on fragments of adrenocorticotropic hormone. Early work examined short ACTH-derived sequences that retained neurotrophic effects while lacking the endocrine activity of the full hormone. Semax entered clinical use in Russia during the 1990s, where it received registration for several neurological indications. Outside that region it remained primarily a laboratory research material rather than an approved therapeutic. English-language literature on it grew more slowly and frequently cited the original Russian studies.
Terminology around the compound varies by source. It appears in catalogues and papers as Semax, as the heptapeptide ACTH(4-7)-Pro-Gly-Pro, and under various alphanumeric laboratory codes used by individual suppliers. These names refer to the same sequence but may imply different salt forms, purity grades, or counter-ions. Peptide databases usually list the free base mass, while product descriptions sometimes report acetate or trifluoroacetate salts with a different formula weight. Because naming conventions for research peptides are not standardised across vendors, checking the declared sequence and measured mass is more reliable than relying on a trade name alone.
Semax is normally supplied as a lyophilized powder, and that form is the most stable. Suppliers commonly recommend storage at -20 °C in a desiccated container protected from light, with short-term handling at room temperature limited to weighing and transfer. Powder that has absorbed moisture degrades faster, so vials should be warmed to ambient temperature before opening to prevent condensation on the contents. Hygroscopic behavior is typical of short hydrophilic peptides, and humidity control matters more than temperature alone for long-term retention.
Once dissolved, the peptide is considerably less stable than the solid. Aqueous solutions are usually prepared at neutral to slightly acidic pH, filtered, and divided into single-use aliquots before freezing. Repeated freeze-thaw cycles are a common cause of avoidable loss and are best prevented by never refreezing a thawed aliquot. Adsorption to plastic and glass surfaces can lower the measured concentration of dilute solutions, particularly below roughly 0.1 mg/mL. Buffer choice, salt content, and container material all influence how much peptide remains detectable after storage.
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.
Imine-based cages aressusceptible to hydrolysis, which could be exploited for controlled release applications. boronic ester groups, which are known to bind diols could be used to recognize sugar analytes. Post-synthetic modification of cage structures is also possible.
=== Rail freight === South Africa has a longer rail network than all other Sub-Saharan African countries combined, at a total length of 23,000 km. Its network also features most of the double track rail in the region. State-owned Transnet Freight Rail is one of the largest players in the region. Approximately 15% of SA's land freight moves by rail. As of 2026, South Africa has three "Bulk Mineral Rail Corridors", which are dedicated heavy haul lines for export minerals. These routes, which total 2,241km, are:
Brettanomyces (Teleomorph Dekkera) Candida (Teleomorphs for different species from several genera including Pichia, Metschnikowia, Issatchenkia, Torulaspora and Kluyveromyces) Kloeckera (Teleomorph Hanseniaspora), usually the most common "wild yeast" found in the vineyard. Some species are known as "killer yeast" that produce inhibitory levels of ethyl acetate and acetic acid that can kill off sensitive strains of Saccharomyces cerevisiae Saccharomycodes Schizosaccharomyces, the only wine yeast that reproduced by fission whereas most wine yeast reproduce by budding. Zygosaccharomyces, very alcohol-tolerant and can grow in wines up to 18% v/v. Additionally this yeast can survive in extremely high sugar levels (as much as 60% w/w or 60 Brix) and is very resistant to sulfur dioxide. Aureobasidium, particularly the "black yeast" species of Aureobasidium pullulans found in moist cellars that can contaminate aging wine in barrels.
Sources: en.wikipedia.org
== Early life and education == Lisa was born in Rochdale in 1978. She had eating problems that began while studying for her GCSEs. Around the age of 15 she became anorexic. She gained all As and A*s in her GCSEs and then achieved four A-Levels which allowed her to take a degree in Russian and Politics at Birmingham University.
=== Catalysis === Ion exchange resins are used in organic synthesis, e.g. for esterification and hydrolysis. Being high surface area and insoluble, they are suitable for vapor-phase and liquid-phase reactions. Examples can be found where basic (OH−-form) of ion exchange resins are used to neutralize of ammonium salts and convert quaternary ammonium halides to hydroxides. Packed-bed reactors with continuous feed enable high turnover numbers and scale-up for industrial synthesis but may prove costly due to catalyst replenishment costs. Furthermore, acidic (H+-form) ion exchange resins have been used as solid acid catalysts for scission of ether protecting groups. and for rearrangement reactions.
cuvette A type of small container used in spectroscopy experiments, usually made of plastic, glass, or quartz and designed to hold a sample (typically a liquid) for measurement inside a spectrometer. Cuvettes should be as clean and transparent as possible to minimize interference with the beams of light on which spectroscopic techniques rely.
Sources: en.wikipedia.org
=== Substrate specificities === Most domains have a very broad substrate specificity and usually only the A-domain determines which amino acid is incorporated in a module. Ten amino acids that control substrate specificity and can be considered the 'codons' of nonribosomal peptide synthesis have been identified, and rational protein design has yielded methodologies to computationally switch the specificities of A-domains. The condensation C-domain is also believed to have substrate specificity, especially if located behind an epimerase E-domain-containing module where it functions as a 'filter' for the epimerized isomer. Computational methods, such as SANDPUMA and NRPSpredictor2, have been developed to predict substrate specificity from DNA or protein sequence data.
The discovery of feathered dinosaurs led to debate regarding whether, and to what extent, Tyrannosaurus might have been feathered. Filamentous structures, which are commonly recognized as the precursors of feathers, have been reported in the small-bodied, basal tyrannosauroid Dilong paradoxus from the Early Cretaceous Yixian Formation of China in 2004. Because integumentary impressions of larger tyrannosauroids known at that time showed evidence of scales, the researchers who studied Dilong speculated that insulating feathers might have been lost by larger species due to their smaller surface-to-volume ratio. The subsequent discovery of the giant species Yutyrannus huali, also from the Yixian, showed that even some large tyrannosauroids had feathers covering much of their bodies, casting doubt on the hypothesis that they were a size-related feature. A 2017 study reviewed known skin impressions of tyrannosaurids, including those of a Tyrannosaurus specimen nicknamed "Wyrex" (HMNS 2006.1743.01, formerly known as BHI 6230) which preserves patches of mosaic scales on the tail, hip, and neck. The study concluded that feather covering of large tyrannosaurids such as Tyrannosaurus was, if present, limited to the upper side of the trunk. A conference abstract published in 2016 posited that theropods such as Tyrannosaurus had their upper teeth covered in lips, instead of bare teeth as seen in crocodilians. This was based on the presence of enamel, which according to the study needs to remain hydrated, an issue not faced by aquatic animals like crocodilians.
== External links == How wounds heal and tumors form With this simple Flash demonstration, Harvard professor Donald Ingber explains how wounds heal, why scars form, and how tumors develop. Presented by Children's Hospital Boston. Wound Healing and Repair Lorenz H.P. and Longaker M.T. Wounds: Biology, Pathology, and Management. Stanford University Medical Center. Romo T. and McLaughlin L.A. 2003. Wound Healing, Skin. Emedicine.com. Rosenberg L. and de la Torre J. 2003. Wound Healing, Growth Factors. Emedicine.com. After the Injury- Children's Hospital Of Philadelphia
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.
Reversed-phase HPLC gives the main purity figure, most often with UV detection near 214 nanometres. Mass spectrometry then confirms the molecular mass. Together the two methods distinguish a correct sequence from a closely related impurity.