The short version of nootropic fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2025-09-28. Anything still debated is marked as such rather than presented as settled.
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.
Solid semax is typically supplied as a lyophilised powder that is hygroscopic and sensitive to moisture, light, and repeated temperature cycling. Long-term storage of the dry peptide is generally recommended at approximately -20 degrees Celsius, while shorter working periods may use refrigeration at 2 to 8 degrees Celsius. Vials should remain tightly closed and desiccated when brought to room temperature, because condensation can damage the material before it is weighed. Dividing a batch into aliquots is preferable to thawing one container repeatedly.
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.
| 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 peptide created in the Soviet Union during the early 1980s by researchers working in Moscow. It was built from the short adrenocorticotropic hormone fragment known as ACTH(4-10), and the chain was then extended with three additional amino acids. The resulting molecule was named semax and entered clinical use in Russia in 1994. It is generally described as a nootropic and neuroprotective agent rather than as a hormone analogue.
The parent fragment ACTH(4-10) carries the sequence Met-Glu-His-Phe-Arg-Trp-Gly. Semax replaces the arginine and tryptophan positions with a proline-glycine-proline tail, giving Met-Glu-His-Phe-Pro-Gly-Pro. That change removes residues associated with adrenal stimulation, so the peptide does not drive cortisol release the way full ACTH does. This distinction shapes how the compound is grouped in the literature, where it sits with neuropeptides and peptide neuromodulators rather than with corticosteroids.
Regulatory status varies sharply by country. Semax is registered for medical use in Russia, where it appears in formularies as a nasal solution, and it also holds registration in a small number of neighbouring states. It has no approval from the United States Food and Drug Administration or the European Medicines Agency, and it is not a scheduled controlled substance in most jurisdictions. Elsewhere it circulates mainly as laboratory material, so purity documentation comes from suppliers rather than from a national pharmacopoeia.
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.
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.
In males, puberty begins with the enlargement of the testicles and scrotum. The penis also increases in size, and a male develops pubic hair. A male's testicles also begin making sperm. The release of semen, which contains sperm and other fluids, is called ejaculation. During puberty, a male's erect penis becomes capable of ejaculating semen and impregnating a female. A male's first ejaculation is an important milestone in his development. On average, a male's first ejaculation occurs at age 13. Ejaculation sometimes occurs during sleep; this phenomenon is known as a nocturnal emission.
== Applications and detection methods == FFF is applicable in the sub-micron range (from 1 nm to several microns) in the "normal" mode or up to 50 microns in the so-called steric mode. The transition from normal to steric mode takes place when diffusion becomes negligible at sizes above a micron. FFF is unique in its wide dynamic range of sizes covering both soluble macromolecules and particles or colloids which can be separated in one analysis. Typical applications are high molar mass polymers and polymer composites, nanoparticles, both industrial and environmental, viruses and virus like particles, lipid nanoparticles, extracellular vesicles and other types of biological samples. FFF can be coupled to all types of detectors known, from high-performance liquid chromatography (HPLC) to size-exclusion chromatography (SEC). Due to FFF's similarity to liquid chromatography (LC), a liquid mobile phase passing through the channel, the most common detectors are those that are also used for liquid chromatography. The most frequently used is an ultraviolet-visible spectroscopy (UV-VIS) detector, because of its non-destructive nature. Coupling with multi angle light scattering which allows the calculation of the size of eluting fractions and comparison to values obtained via FFF theory. Another popular detector is inductively coupled plasma mass spectrometry to characterize metallic nanoparticles with high specificity and sensitivity.
A coordination complex is a chemical compound consisting of a central atom or ion, which is usually metallic and is called the coordination centre, and a surrounding array of bound molecules or ions, that are in turn known as ligands or complexing agents. Many metal-containing compounds, especially those that include transition metals (elements like titanium that belong to the periodic table's d-block), are coordination complexes. Coordination complexes can have a wide variety of coordination numbers and molecular geometries, with some complexes exhibiting Jahn–Teller distortions. Additionally, most coordination complexes are colored, due to visible light absorption due to d-d transitions or charge-transfer. The two main models explaining the properties (such as electronic structure, magnetism, and color) of complexes are crystal field theory and ligand field theory.
Sources: en.wikipedia.org
=== 12 February === Ukrainian data indicated that Russian soldiers were suffering their highest losses since the first week of the war, at 824 soldiers killed per day in February. The UK Ministry of Defence said that the data was "likely accurate". In June and July around 172 Russian soldiers were killed per day. Ukraine was suffering a high attritional rate as well. The Wagner Group captured the village of Krasna Hora north of Bakhmut. The United States embassy in Moscow advised all American citizens to immediately leave Russia due to the ongoing war in Ukraine, citing the "risk of wrongful detentions".
Tumor biopsy samples used for diagnostics always contain as little as 5% of the target variant as compared to wildtype sequence. Also, for noninvasive applications from peripheral blood or urine, the DNA test must be specific enough to detect mutations at variant allele frequencies of less than 0.1%. Currently, by optimizing the traditional PCR, there's a new invention, amplification-refractory mutation system (ARMS) is a method for detecting DNA sequence variants in cancer. The principle behind ARMS is that the enzymatic extension activity of DNA polymerases is highly sensitive to mismatches near the 3' end of primer. Many different companies have developed diagnostics tests based on ARMS PCR primers. For instance, Qiagen therascreen, Roche cobas and Biomerieux THxID have developed FDA approved PCR tests for detecting lung, colon cancer and metastatic melanoma mutations in the KRAS, EGFR and BRAF genes. Their IVD kits were basically validated on genomic DNA extracted from FFPE tissue. There are also microarrays that utilize hybridization mechanism to diagnose cancer. More than a million of different probes can be synthesized on an array with Affymetrix's Genechip technology with a detection limit of one to ten copies of mRNA per well. Optimized microarrays are typically considered to produce repeatable relative quantitation of different targets.
== Toxic impurity == In 1976, a 23-year-old graduate student in chemistry named Barry Kidston was searching for a way to make a legal recreational drug. Having read the paper by Ziering and Lee, he deduced that he could make a drug with pethidine's effects without its legal restrictions, because desmethylprodine is a different molecule and had never been addressed by law. Kidston successfully synthesized and used desmethylprodine for several months, after which he suddenly came down with the symptoms of Parkinson's disease and was hospitalized. Physicians were perplexed, because Parkinson's disease would be a great rarity in someone so young, but L-DOPA, the standard drug for Parkinson's, relieved his symptoms. L-DOPA is a precursor for dopamine, the neurotransmitter whose lack produces Parkinson's symptoms. It was later found that his development of Parkinson's was due to a common impurity in the synthesis of MPPP called 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a neurotoxin that specifically targets dopamine-producing neurons. The intermediate tertiary alcohol is liable to dehydration in acidic conditions if the reaction temperature rises above 30 °C. Kidston did not realize this and esterified the intermediate with propionic anhydride at an elevated temperature. Consequently, he produced MPTP as a major impurity. 1-Methyl-4-phenylpyridinium (MPP+), a metabolite of MPTP, causes rapid onset of irreversible symptoms similar to Parkinson's disease. MPTP is metabolized to the neurotoxin MPP+ by the enzyme MAO-B, which is expressed in glial cells.
Sources: en.wikipedia.org
On the same day the ICJ's ruling was made public, South African prime minister B. J. Vorster rejected it as "politically motivated", with no foundation in fact. However, the decision inspired the bishops of the Evangelical Lutheran Ovambo-Kavango Church to draw up an open letter to Vorster denouncing apartheid and South Africa's continued rule. This letter was read in every black Lutheran congregation in the territory, and in a number of Catholic and Anglican parishes elsewhere. The consequence of the letter's contents was increased militancy on the part of the black population, especially among the Ovambo people, who made up the bulk of SWAPO's supporters. Throughout the year there were mass demonstrations against the South African government held in many Ovamboland schools. In December 1971, Jannie de Wet, Commissioner for the Indigenous Peoples of South West Africa, sparked off a general strike by 15,000 Ovambo workers in Walvis Bay when he made a public statement defending the territory's controversial contract labour regulations. The strike quickly spread to municipal workers in Windhoek, and from there to the diamond, copper and tin mines, especially those at Tsumeb, Grootfontein, and Oranjemund. Later in the month, 25,000 Ovambo farm labourers joined what had become a nationwide strike affecting half the total workforce. The South African police responded by arresting some of the striking workers and forcibly deporting the others to Ovamboland.
negative control Also negative regulation. The inhibition or deactivation of some biological process caused by the presence of a specific molecular entity (e.g. a repressor), in the absence of which the process is not inhibited and thus can proceed normally. In gene regulation, for example, a repressor may bind to an operator upstream from a coding sequence and prevent access by transcription factors and/or RNA polymerase, thereby blocking the gene's transcription. This is contrasted with positive control, in which the presence of an inducer is necessary to switch on transcription.
Romania is the largest country in Southeastern Europe and the twelfth-largest in Europe, having an area of 238,397 square kilometres (92,046 sq mi). It lies between latitudes 43° and 49° N and longitudes 20° and 30° E. The terrain is distributed roughly equally between mountains, hills, and plains. The Carpathian Mountains dominate the centre of Romania, with 14 mountain ranges reaching above 2,000 m or 6,600 ft—the highest is Moldoveanu Peak at 2,544 m or 8,346 ft. They are surrounded by the Moldavian and Transylvanian plateaus, the Pannonian Plain and the Wallachian plains. Romania is home to six terrestrial ecoregions: Balkan mixed forests, Central European mixed forests, East European forest steppe, Pannonian mixed forests, Carpathian montane conifer forests, and Pontic steppe. Natural and semi-natural ecosystems cover about 47% of the country's land area. There are almost 10,000 km2 (3,900 sq mi) (about 5% of the total area) of protected areas in Romania covering 13 national parks and three biosphere reserves. The Danube river forms a large part of the border with Serbia and Bulgaria, and flows into the Black Sea, forming the Danube Delta, which is the second-largest and best-preserved delta in Europe, and a biosphere reserve and a biodiversity World Heritage Site. At 5,800 km2 (2,200 sq mi), the Danube Delta is the largest continuous marshland in Europe, and supports 1,688 different plant species alone. Romania has one of the largest areas of undisturbed forest in Europe, covering almost 27% of its territory.
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.
Dry powder is usually kept at about -20 degrees Celsius for long-term storage and at 2 to 8 degrees Celsius for short working periods. Containers should stay sealed and protected from light and moisture to limit degradation.