intranasal route 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 2025-12-04 and is reviewed periodically as new material appears.
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.
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.
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.
Common degradation pathways include oxidation of the methionine side chain, hydrolysis of the peptide backbone, and aggregation under unfavourable pH or concentration. Stability studies typically monitor the main peak by chromatography and report total related substances as a percentage. Because no official monograph exists, acceptance criteria vary between laboratories, and reported purity values are not directly comparable across suppliers. Analysts therefore document the method, column, and detection wavelength alongside each result, and open questions remain about how much biological activity the oxidised forms retain.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide (ACTH fragment analog) | Not a steroid; does not belong to the melanocortin agonist drugs by marketing category |
| Molecular formula | C37H51N9O10S (commonly cited) | Reported values vary slightly with salt and counter-ion content |
| Appearance | White to off-white lyophilized powder | A single batch may appear as a loose cake or fluffy solid |
| Solubility | Freely soluble in water and aqueous buffer | Stock solutions are usually prepared in sterile water or saline |
| Typical storage | −20 °C or below, desiccated and protected from light | Seal opened vials promptly to limit moisture uptake |
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。
各国监管态度分化明显。俄罗斯按处方药管理，部分东欧国家留有使用记录；欧盟与美国未批准其作为药物上市，市面流通品通常标注为研究用化学品。身份差异意味着标示含量、纯度与无菌性缺少统一核查。体育领域还牵涉反兴奋剂名录，跨境携带则受目的地药品法规约束。
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.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It corresponds to the ACTH(4-7) fragment extended at the C-terminus by a Pro-Gly-Pro tripeptide, an addition intended to slow enzymatic breakdown. The molecular formula is C37H51N9O10S and the molecular mass is approximately 814 daltons. In the literature it is often described as an ACTH(4-10) analog, although that label reflects a naming convention as much as a precise structural relationship. The compound was developed in Russia and remains most closely associated with that research tradition.
Laboratory descriptions of the material are consistent across suppliers. It appears as a white to off-white lyophilized powder that dissolves readily in water and in polar organic solvents such as dimethyl sulfoxide. Aqueous solutions are clear and colorless at low concentrations. Because the peptide contains methionine, oxidation at the sulfur atom is a recognized degradation pathway, and handling notes usually call for protected, desiccated storage. Reported purity for research-grade lots is generally above 95 percent as measured by reversed-phase high-performance liquid chromatography.
The compound is registered in Russia as a pharmaceutical product, most commonly formulated as a nasal solution, and has been used in that setting since the 1990s. Outside that jurisdiction it is generally handled as a research chemical rather than an approved medicine. Regulatory status therefore differs sharply between countries, and material sold internationally may not correspond to the Russian pharmaceutical formulation. Documentation with commercial samples is typically limited to a certificate of analysis covering purity and identity, not clinical status or local legal classification.
== History == Vitamin A toxicity is known to be an ancient phenomenon; fossilized skeletal remains of early humans suggest bone abnormalities may have been caused by hypervitaminosis A, as observed in a fossilised leg bone of an individual of Homo erectus, which bears abnormalities similar to those observed in people suffering from an overdose of Vitamin A in the present day. Vitamin A toxicity has long been known to the Inuit, as they will not eat the liver of polar bears or bearded seals due to them containing dangerous amounts of Vitamin A. It has been known to Europeans since at least 1597 when Gerrit de Veer wrote in his diary that, while taking refuge in the winter in Nova Zemlya, he and his men became severely ill after eating polar bear liver. It is claimed that, in 1913, Antarctic explorers Douglas Mawson and Xavier Mertz were both poisoned (and Mertz died) from eating the livers of their sled dogs during the Far Eastern Party. Another study suggests, however, that exhaustion and diet change are more likely to have caused the tragedy.
aminoacyl-tRNA (aa-tRNA) Also aminoacylated tRNA and charged tRNA. A transfer RNA to which a cognate amino acid is chemically bonded; i.e. the product of a transesterification reaction catalyzed by an aminoacyl-tRNA synthetase. Aminoacyl-tRNAs bind to the aminoacyl site of the ribosome during translation.
=== Triacidic bases === When one molecule of base via complete ionization produces three hydroxide ions, the base is said to be triacidic or triprotic. Examples of triacidic bases are: Aluminium hydroxide, ferric hydroxide, gold(III) hydroxide.
Other psychedelics not belonging to any of the above three structural families have been discovered, for instance certain arylpiperazine derivatives like quipazine, the antiretroviral drug efavirenz, and simplified or partial lysergamides (which are also conformationally constrained tryptamines and/or phenethylamines) like NDTDI (9-nor-LSD; 8,10-seco-LSD) and UCD0120 (dides-B,C-LSD).
Claire fixes up his wound and a bond develops between the two; she allows McCormick to stay, and he and Nat later build a simulated bomber-plane cockpit in Nat's treehouse so that McCormick can teach Nat how to fly. McCormick passes out and is hospitalized, where he discovers his body is failing as his age begins to catch up to him. McCormick tracks down Finley's daughter Susan, who informs him her father died in a lab fire before she was born. The FBI discovers there was a warehouse lab fire in the early 40s, and all the scientists including Finley died trying to save the frozen McCormick from the chaos. In the aftermath of the fire, people mistook the cryonics chamber for a water heater, not knowing that McCormick was inside, resulting in him being accidentally frozen for 53 years. She gives McCormick her father's journals, detailing the cryogenic process, and Finley's notes disclose that the rapid aging is irreversible. Susan also reveals that Helen is still alive, but they escape before the FBI, who is now after McCormick, catch up to them. Claire drives McCormick to an air show where he commandeers a B-25 bomber to fly to Helen's seaside-lighthouse home, with Nat stowing away on board. Claire gives Harry's journals to the FBI, for their plans to replicate and modernize the experiment. McCormick suffers another aging attack, forcing Nat (who is now slightly familiar with the plane's controls after his simulated-training session with McCormick) to land the plane in the field near Helen's house.
Sources: en.wikipedia.org
== Summary table for each class of nuclides == This is a summary table for the 987 nuclides with half-lives longer than one hour, given in List of nuclides. Note that that number, while exact to present knowledge, will likely change slightly in the future, as some "stable" nuclides are observed to be radioactive with very long half-lives, and some half-lives or known radioactive ones are revised.
== Awards and honours == 2020 Preis der Stadt Wien für Naturwissenschaften 2017 European Research Council (ERC) Advanced Grant 2015 Honorary member of the Swiss Society for Allergology and Immunology 2010 Virchow Medal, Medical Faculty, University of Würzburg 2012 European Research Council (ERC) Advanced Grant 2009 Full member of the Austrian Academy of Sciences 2005 Corresponding member of the Austrian Academy of Sciences 2001 Wittgenstein Award 2000 Member of the Academia Europaea 1990 Member of the European Molecular Biology Organization (EMBO) 1981 Postdoctoral fellowship (Swiss National Science Foundation)
•NO + O3 → •NO2 + O2 + hν The activated NO2[◊] luminesces broadband visible to infrared light as it reverts to a lower energy state. A photomultiplier and associated electronics count the photons that are proportional to the amount of nitric oxide (NO) present. To determine the amount of nitrogen dioxide, NO2, in a sample (containing no NO), it must first be converted to NO by passing the sample through a converter before the above ozone activation reaction is applied. The ozone reaction produces a photon count proportional to NO that is proportional to NO2 before it was converted to NO. In the case of a mixed sample that contains both NO and NO2, the above reaction yields the amount of NO and NO2 combined in the air sample, assuming that the sample is passed through the converter. If the mixed sample is not passed through the converter, the ozone reaction produces activated NO2[◊] only in proportion to the NO in the sample. The NO2 in the sample is not activated by the ozone reaction. Though unactivated NO2 is present with the activated NO2[◊], photons are emitted only by the activated species that is proportional to original NO. The final step is to subtract NO from (NO + NO2) to yield NO2
Valerie Joy Beynon. For services to the community in Cobham, Surrey. Elizabeth Kay Billington. Chair, Kushti Bok and Vice-Chair, Dorset Council Gypsy Traveller Forum. For services to the Gypsy and Traveller Community in Dorset. William Archibald Bingham. Chair, Newcastle and Mourne Cancer Research Committee. For services to Cancer Research Fundraising in County Down. Chandra Shekhar Biyani. Consultant Urological Surgeon, Leeds Teaching Hospitals NHS Trust. For services to Medical Education. Reverend Christine Fiona Blackman. For services to the community in Reading, Berkshire. Derek John Bland. For services to the community in Northamptonshire. Roberta Vivian Lindsay Blyth. For services to the community in Roade, Northamptonshire. Winifred Patricia Bownes. Volunteer Coordinator, Cookstown Monday Club. For services to the community in Cookstown, County Tyrone. Mary Boyes. Cleaner, North Shore Academy, Stockton-on-Tees. For services to Education. John Robert Boyne-Aitken. For services to Heritage Crafts. Evelyn Lettita Bracey. For services to the community in Wantage, Oxfordshire. Paul Mark Brackley. Community First Responder, Oundle Community First Responders. For services to the community in Oundle and North Northamptonshire. Christopher Samuel Bradbury. For services to the community in Reedham, Norfolk. Moira Jeanette Brock. Founder and Principal, La Danse Fantastique. For services to Young People in Basildon, Essex. Anna Theresa Margaret Brown. For services to the NHS and to the community in the London Borough of Richmond-upon-Thames. Dennis Sydney Brown.
Sources: en.wikipedia.org
It is a short synthetic peptide built from seven amino acids: methionine, glutamic acid, histidine, phenylalanine and three prolines. The sequence derives from the 4-10 fragment of adrenocorticotropic hormone with an added proline-glycine-proline tail. No plant or animal extract is involved; the material is produced by solid-phase peptide synthesis.
It was developed in the Soviet Union during the early 1980s by groups at the Institute of Molecular Genetics in Moscow. Russian approval for intranasal use followed, and it has been marketed there since. Western laboratories encountered it mainly through translated literature and, later, through online research-chemical trade.
It holds a Russian registration as a prescription nasal product but has no approval from the European Medicines Agency or the United States Food and Drug Administration. Buyers outside Russia usually receive material sold strictly for laboratory research. That distinction matters because research-grade and pharmaceutical-grade products carry different documentation and testing expectations.
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.