If you have been reading about synthetic heptapeptide 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.
Last reviewed on 2026-06-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. The first four residues correspond to the ACTH(4-10) fragment, while the terminal Pro-Gly-Pro extension was added to improve metabolic stability. Its molecular formula is C37H51N9O10S and its monoisotopic mass is approximately 813.9 Da. The compound is classified as a peptide research chemical and as a registered pharmaceutical product in Russia, but it does not hold marketing approval in the European Union or the United States. Naming conventions vary across supplier catalogs.
Development of the compound took place in the Soviet Union during the 1980s, largely through peptide research groups affiliated with the Shemyakin-Ovchinnikov Institute and Moscow State University. Investigators screened fragments of adrenocorticotropic hormone for activity on the central nervous system while attempting to separate cognitive effects from hormonal ones. The shortened sequence was selected because it retained behavioral activity in animal models without stimulating corticosteroid release. Early publications described the molecule as an ACTH(4-10) analog.
Published studies examine a fairly narrow set of endpoints. Rodent experiments commonly measure maze learning, infarct volume after induced ischemia, and tissue levels of neurotrophic factors. Clinical reports from Russian centres describe attention, memory and recovery scores in patients after stroke or transient ischemic attack. Most of those human studies are small and few have been repeated by independent groups. Outcome measures differ between studies, which limits direct comparison.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Seven-residue peptide |
| Molecular mass | 813.9 Da | Monoisotopic value |
| Appearance | White to off-white powder | Lyophilized form |
| Solubility | Freely soluble in water | Also soluble in saline and polar solvents |
| Storage (dry) | -20 °C or lower | Desiccated, protected from light |
Regulatory status differs sharply between jurisdictions. In Russia the peptide is registered as a prescription nasal preparation, while agencies such as the United States Food and Drug Administration have not approved it for any indication. Products sold elsewhere are typically labeled for laboratory research only, and such labels shift responsibility for safe handling to the purchaser. Because the same name covers pharmaceutical-grade nasal drops and bulk research powder, identity and purity documentation becomes the main practical concern when comparing sources.
Semax is a synthetic seven-amino-acid peptide whose sequence extends the ACTH(4-10) fragment with a C-terminal proline-glycine-proline tripeptide. The commonly cited sequence is Met-Glu-His-Phe-Pro-Gly-Pro, giving a molecular formula near C37H51N9O10S and a molecular weight close to 813.9 g/mol. It belongs to the broader class of synthetic ACTH fragments studied for central nervous system effects rather than for adrenal steroid stimulation. In practice the material appears as a lyophilized white powder for laboratory work or as a dilute saline solution in clinical settings.
Development is attributed to researchers at the Institute of Molecular Genetics in Moscow during the early 1980s, building on earlier Soviet work with ACTH fragments. Russian regulatory approval followed for intranasal use, and the compound has remained commercially available there for decades. Most published human data originate from Russian and, later, some Eastern European clinical reports, which are not always accessible in English translation. Outside that region the material is generally handled as a research chemical rather than a licensed medicine.
Dissolution is normally performed in water, phosphate-buffered saline, or normal saline, since the peptide is freely soluble in aqueous media and is rarely handled with strong organic solvents. Solution pH should be kept near neutral, because extreme acidity or alkalinity accelerates backbone hydrolysis and encourages oxidation of the methionine side chain. Once dissolved, the material is less stable than the dry powder and is commonly divided into single-use portions and frozen. Buffers containing primary amines, such as Tris, are often avoided because of possible side reactions.
Purity assessment relies mainly on reversed-phase high-performance liquid chromatography, which separates the target heptapeptide from truncated sequences, deletion analogues, and oxidised forms. Mass spectrometry, usually coupled to liquid chromatography, confirms identity through the expected molecular ion and reveals modifications such as methionine sulfoxide formation. Amino acid analysis can verify composition, and tandem mass spectrometry supports sequence confirmation. Ultraviolet detection near 254 to 280 nanometres is convenient because the phenylalanine and histidine residues absorb in that region. Nuclear magnetic resonance is rarely used for routine release testing.
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。
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.
It is thought that high glucagon levels and lack of insulin production are the main triggers for the metabolic issues associated with Type I diabetes, in particular maintaining normal blood glucose levels, formation of ketone bodies, and formation of urea. One finding of note is that the glucagon response to hypoglycemia is completely absent in patients with Type I diabetes. Consistently high glucagon concentrations in the blood can lead to diabetic ketoacidosis, which is when ketones from lipid breakdown build up in the blood, which can lead to dangerously low blood glucose levels, low potassium levels, and in extreme cases cerebral edema. It has been proposed that the reason for the high levels of glucagon found in the plasma of patients with Type I diabetes is the absence of beta cells producing insulin and the reciprocal effect this has on delta cells and the secretion of somatostatin.
Antidotes are agents that can neutralise the effects of a poison or toxin. Antidotes counteract the effects of toxins in many ways, such as by blocking the absorption of the toxin, binding and neutralising the poison, opposing the toxin's end-organ function, or blocking the toxin's conversion to more hazardous metabolites. In addition to lowering the amount of free or active poison present, antidote delivery may also lessen the toxin's effects on organs through competitive inhibition, receptor blockage, or direct antagonistic interaction. The therapeutic index or ratio (TD50/ED50), which is the ratio of the toxic dosage (TD) or fatal dose (LD) to the effective dose (ED), determines the level of safety associated with a substance.
== History == Midazolam is among about 35 benzodiazepines currently used medically, and was synthesized in 1975 by Walser and Fryer at Hoffmann-LaRoche, Inc in the United States. Owing to its water solubility, it was found to be less likely to cause thrombophlebitis than similar drugs. The anticonvulsant properties of midazolam were studied in the late 1970s, but not until the 1990s did it emerge as an effective treatment for convulsive status epilepticus. As of 2010, it is the most commonly used benzodiazepine in anesthetic medicine. In acute medicine, midazolam has become more popular than other benzodiazepines, such as lorazepam and diazepam, because it is shorter lasting, is more potent, and causes less pain at the injection site. Midazolam is also becoming increasingly popular in veterinary medicine due to its water solubility. In 2018 it was revealed the CIA considered using midazolam as a "truth serum" on terrorist suspects in project "Medication".
== Diagnosis == In order to assess lactose intolerance, intestinal function is challenged by ingesting more dairy products than can be readily digested. Clinical symptoms typically appear within 30 minutes, but may take up to two hours, depending on other foods and activities. Substantial variability in response (symptoms of nausea, cramping, bloating, diarrhea, and flatulence) is to be expected, as the extent and severity of lactose intolerance varies among individuals. The next step is to determine whether it is due to primary lactase deficiency or an underlying disease that causes secondary lactase deficiency. Physicians should investigate the presence of undiagnosed celiac disease, Crohn's disease, or other enteropathies when secondary lactase deficiency is suspected and infectious gastroenteritis has been ruled out. Lactose intolerance is distinct from milk allergy, an immune response to cow's milk proteins. They may be distinguished in diagnosis by giving lactose-free milk, producing no symptoms in the case of lactose intolerance, but the same reaction as to normal milk in the presence of a milk allergy. A person can have both conditions. If positive confirmation is necessary, four tests are available.
Sources: en.wikipedia.org
As an oceanic organism, O. vulgaris experiences a temperature variance due to many factors, such as season, geographical location, and depth. For example, octopuses living around Naples may experience a temperature of 25 °C (77 °F) in the summer and 15 °C (59 °F) in the winter. These changes would occur quite gradually, however, and thus would not require any extreme regulation. The common octopus is a poikilothermic, eurythermic ectotherm, meaning that it conforms to the ambient temperature. This implies that no real temperature gradient is seen between the organism and its environment, and the two are quickly equalized. If the octopus swims to a warmer locale, it gains heat from the surrounding water, and if it swims to colder surroundings, it loses heat in a similar fashion. O. vulgaris can apply behavioral changes to manage wide varieties of environmental temperatures. Respiration rate in octopods is temperature-sensitive – respiration increases with temperature. Its oxygen consumption increases when in water temperatures between 16 and 28 °C (61 and 82 °F), reaches a maximum at 28 °C (82 °F), and then begins to drop at 32 °C (90 °F). The optimum temperature for metabolism and oxygen consumption is between 18 and 24 °C (64 and 75 °F). Variations in temperature can also induce a change in hemolymph protein levels along oxygen consumption. As temperature increases, protein concentrations increase in order to accommodate the temperature. Also the cooperativity of hemocyanin increases, but the affinity decreases.
Christians constitute the majority of the city's population, most of whom follow the Russian Orthodox Church. The Patriarch of Moscow serves as the head of the Church and lives in the Danilov Monastery. Moscow was called the "city of 40 times 40 churches"—before the Russian Revolution in 1917. Moscow is Russia's capital of Eastern Orthodox Christianity, which has been the country's traditional religion. Other religions practiced in Moscow include Buddhism, Hinduism, Islam, Judaism, Yazidism, and Rodnovery (Slavic Native Faith). The Moscow Mufti Council claimed that Muslims numbered around 1.5 million of the city's 10.5 million population in 2010. The city has four mosques.
=== Exercise and muscle soreness === A 2017 review showed that taking antioxidant dietary supplements before or after exercise is unlikely to produce a noticeable reduction in muscle soreness after a person exercises.
==== MeSH E05.337.550 – drug evaluation, preclinical ==== MeSH E05.337.550.200 – drug screening assays, antitumor MeSH E05.337.550.200.800 – tumor stem cell assay MeSH E05.337.550.200.900 – xenograft model antitumor assays MeSH E05.337.550.200.900.830 – subrenal capsule assay MeSH E05.337.550.400 – microbial sensitivity tests MeSH E05.337.550.400.800 – serum bactericidal test MeSH E05.337.550.600 – parasitic sensitivity tests
== Spectrum == The mass spectrum of the secondary ions emitted from the bombarded surface during SSIMS provides direct information of not only the chemical composition but also of the chemical structure of the bombarded area. This is because the mass spectrum includes cluster ions as well as elemental ions. These cluster ions reflect the surface chemistry in a detailed way. The figure shows the mass spectrum obtained from a SSIMS analysis of polytetrafluoroethylene (PTFE). The positive ion spectrum shows positive atomic ions (i.e. C+) and molecular ions (i.e. CF+, CF3+, C3F3+) of the target. The negative ion spectrum shows negative atomic ions (i.e. F−) and molecular ions (i.e. F2−, CF3−, C3F3−).
Sources: en.wikipedia.org
It is a synthetic peptide of seven amino acids. Its backbone corresponds to a fragment of adrenocorticotropic hormone extended at the carboxyl end. The material is distributed as a lyophilized solid for laboratory use.
The extension was introduced to slow enzymatic breakdown of the peptide in biological systems. Natural ACTH fragments are degraded rapidly by peptidases. Adding the tripeptide was intended to extend the window during which the molecule remains intact.
Most published work consists of animal experiments conducted in a small number of laboratories. Human data are limited in number and size. Whether the observed effects translate into reliable clinical benefit is still unresolved.
It consists mainly of animal experiments and small clinical reports, with much of the clinical material published in Russian-language journals. Large independent trials are scarce. Separating reliable effects from chance findings is consequently difficult.