The short version of nootropic fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-07-05 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.
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.
==== Antigenic stability and cross-reactive antibodies ==== All viruses in the family Paramyxoviridae are antigenically stable; therefore the family representatives that are close relatives and belong to the same genus, most likely, share common antigenic determinants. Thus, porcine parainfluenza 1, which has high sequence homology with SeV and also belongs to the same genus Respirovirus as SeV, probably, has cross-reactive antibodies with SeV. Perhaps the porcine parainfluenza 1 was responsible for pigs disease in Japan in 1953–1956. However, the antigenic cross-reactivity among these two representatives within the genus Respirovirus may explain why SeV antibodies were found in sick pigs, and why it was thought that SeV was the etiological causative agent of pigs disease. Human parainfluenza virus type 1 also shares common antigenic determinants with SeV and triggers the generation of cross-reactive neutralizing antibodies. This fact can explain wide spread detection of SeV antibodies in humans in the 1950s–1960s. Recently published study also showed this wide spread detection. The study that was published in 2011 demonstrated that SeV neutralizing antibodies (which were formed due to human parainfluenza virus type 1 past infection) can be detected in 92.5% of human subjects worldwide with a median EC50 titer of 60.6 and values ranging from 5.9 to 11,324. Low anti-SeV antibodies background does not block the ability of SeV-base vaccine to promote antigen-specific T cell immunity.
== Medical uses == Blood is normally sterile. The presence of bacteria in the blood is termed bacteremia, and the presence of fungi is called fungemia. Minor damage to the skin or mucous membranes, which can occur in situations like toothbrushing or defecation, can introduce bacteria into the bloodstream, but this bacteremia is normally transient and is rarely detected in cultures because the immune system and reticuloendothelial system quickly sequester and destroy the organisms. Bacteria can enter the blood from infections such as cellulitis, UTIs and pneumonia; and infections within the vascular system, such as bacterial endocarditis or infections associated with intravenous lines, may result in a constant bacteremia. Fungemia occurs most commonly in people with poorly functioning immune systems. If bacteria or fungi are not cleared from the bloodstream, they can spread to other organs and tissues, or evoke an immune response that leads to a systemic inflammatory condition called sepsis, which can be life-threatening. When sepsis is suspected, it is necessary to draw blood cultures to identify the causative agent and provide targeted antimicrobial therapy. People who are hospitalized and have a fever, a low body temperature, a high white blood cell count or a low count of granulocytes (a category of white blood cells) commonly have cultures drawn to detect a possible bloodstream infection.
=== Disadvantages === Typically the cost of a single synthesis or sample assessment are expensive to set up and start up cost for automation can be expensive (but see above "Low-cost laboratory robotics"). Many techniques have not been developed for automation yet. Additionally there is difficulty automating instances where visual analysis, recognition, or comparison is required such as color changes. This also leads to the analysis being limited by available sensory inputs. One potential disadvantage is an increases job shortages as automation may replace staff members who do tasks easily replicated by a robot. Some systems require the use of programming languages such as C++ or Visual Basic to run more complicated tasks.
Sources: en.wikipedia.org
==== Clean vehicle and clean energy home improvement tax credits eliminated ==== The tax credit for buying a new qualified electric vehicle or fuel cell electric vehicle is no longer available for purchases made after September 30, 2025. The tax credit for buying a used qualified electric vehicle or fuel cell vehicle from a licensed dealer is no longer available for purchases made after September 30, 2025. The tax credit for installing property to either recharge electric vehicles or to store or dispense clean-burning fuel will no longer be available after June 30, 2026. The tax credit for making qualified energy-efficient improvements to one's home will no longer be available for improvements put into service after December 31, 2025. The tax credit for installing solar electric panels, solar water heaters, wind turbines, geothermal heat pumps, fuel cells, or battery storage technology in one's home will no longer be available for improvements made after December 31, 2025.
=== Heating === In January 2023, Forbes reported that a "heating" tool allows TikTok to manually promote certain videos, comprising 1–2% of daily views. The practice began as a way to grow and diversify content and influencers that were not automatically picked up by the recommendation algorithm. It was also used to promote brands, artists, and NGOs, such as the FIFA World Cup and Taylor Swift. However, some employees have abused it to promote their own accounts or those of their spouses, while others have felt that their guidelines leave too much room for discretion. TikTok said only a few individuals can approve heating in the US and the promoted videos take up less than 0.002% of user feeds. To address concerns of Chinese influence, the company is negotiating with the Committee on Foreign Investment in the United States (CFIUS) such that future heating could only be performed by vetted security personnel in the US and the process would be audited by third-parties such as Oracle.
== Interactions == There are several notable drug interactions with progesterone. Certain selective serotonin reuptake inhibitors (SSRIs) such as fluoxetine, paroxetine, and sertraline may increase the GABAA receptor-related central depressant effects of progesterone by enhancing its conversion into 5α-dihydroprogesterone and allopregnanolone via activation of 3α-HSD. Progesterone potentiates the sedative effects of benzodiazepines and alcohol. Notably, there is a case report of progesterone abuse alone with very high doses. 5α-Reductase inhibitors such as finasteride and dutasteride inhibit the conversion of progesterone into the inhibitory neurosteroid allopregnanolone, and for this reason, may have the potential to reduce the sedative and related effects of progesterone. Progesterone is a weak but significant agonist of the pregnane X receptor (PXR), and has been found to induce several hepatic cytochrome P450 enzymes, such as CYP3A4, especially when concentrations are high, such as with pregnancy range levels. As such, progesterone may have the potential to accelerate the metabolism of various medications.
Sources: en.wikipedia.org
==== MeSH E05.478.605 – immunoprecipitation ==== MeSH E05.478.605.160 – chromatin immunoprecipitation MeSH E05.478.605.492 – precipitin tests MeSH E05.478.605.492.300 – flocculation tests MeSH E05.478.605.492.350 – immunodiffusion MeSH E05.478.605.492.350.350 – immunoelectrophoresis MeSH E05.478.605.492.350.350.150 – counterimmunoelectrophoresis MeSH E05.478.605.492.350.350.350 – immunoelectrophoresis, two-dimensional MeSH E05.478.605.825 – radioimmunoprecipitation assay
where De is the effective dose, B bioavailability and Da the administered dose. Therefore, if a drug has a bioavailability of 0.8 (or 80%) and it is administered in a dose of 100 mg, the equation will demonstrate the following:
=== Scalp hair loss === Clascoterone is under development for the treatment of androgen-dependent scalp hair loss. Two phase 3 clinical trials were completed and disclosed in December 2025. The drug significantly improved hair growth in both trials. More specifically, target area hair count (TAHC) had a relative improvement of 5.39-fold (539%) in one study and of 1.68-fold (168%) in the other study, both compared to placebo. In other words, hair growth improved in both the placebo and clascoterone groups, but growth improved by about 1.7- to 5.4-fold more with clascoterone than with placebo. The actual absolute changes in hair counts in the different groups have not yet been released.
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.