If you have been reading about lyophilized powder 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 2026-06-22. Numbers and descriptions here follow the published literature rather than marketing material.
The proposed mechanism centres on neurotrophic signalling rather than direct receptor activation. Semax is reported to increase expression of brain-derived neurotrophic factor and nerve growth factor in several brain regions, and to shift the balance between excitatory and inhibitory neurotransmitter systems. Interaction with melanocortin receptors has been suggested because of the parent ACTH fragment. Many of these findings come from rodent studies, and the extent to which they translate to human physiology remains an open question.
Scientific literature on semax is unevenly distributed. A substantial share of published work originates from a small number of laboratories in Russia, while independent replication elsewhere is limited. Human data consist mostly of small trials with short follow-up, and several reported outcomes rely on subjective rating scales. Questions about how much intact peptide reaches the central nervous system after nasal administration, and how long it persists there, are still unresolved. The compound is best described as an active research subject rather than a settled pharmacological agent.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It was derived from the ACTH(4-10) fragment, a short segment of adrenocorticotropic hormone that lacks the hormonal activity associated with the full-length peptide. Researchers at the Institute of Molecular Genetics in Moscow developed the compound during the 1980s. It has been registered as a pharmaceutical product in Russia and several neighbouring countries, where it is supplied as a nasal solution, and it is also sold internationally as a research chemical.
Identity and purity are established with standard peptide methods. Reversed-phase HPLC with ultraviolet detection near 214 nm resolves the parent peak from deletion and truncation byproducts, and reports typically quote a main-peak percentage. Mass spectrometry by electrospray or MALDI-TOF confirms the expected molecular mass, while amino acid analysis or peptide mapping can verify composition when the sequence itself is in question. A certificate of analysis that pairs a chromatogram with a mass spectrum is more informative than a purity figure alone. Counter-ion content and residual solvents are separate specifications and are frequently omitted.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Calculated for the free peptide |
| Molar mass | 813.9 g/mol | Anhydrous free base |
| Peptide class | Synthetic heptapeptide | ACTH(4-10) analogue |
| Parent fragment | ACTH(4-10) | Adrenocorticotropic hormone segment |
| Developmental origin | Institute of Molecular Genetics, Moscow | Work began in the 1980s |
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.
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.
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.
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。
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。
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.
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.
Alkaloid-containing plants have been used by humans since ancient times for therapeutic and recreational purposes. For example, medicinal plants have been known in Mesopotamia from about 2000 BC. The Odyssey of Homer referred to a gift given to Helen by the Egyptian queen, a drug bringing oblivion. It is believed that the gift was an opium-containing drug. A Chinese book on houseplants written in 1st–3rd centuries BC mentioned a medical use of ephedra and opium poppies. Also, coca leaves have been used by Indigenous South Americans since ancient times. Extracts from plants containing toxic alkaloids, such as aconitine and tubocurarine, were used since antiquity for poisoning arrows. Studies of alkaloids began in the 19th century. In 1804, the German chemist Friedrich Sertürner isolated from opium a "soporific principle" (Latin: principium somniferum), which he called "morphium", referring to Morpheus, the Greek god of dreams; in German and some other Central-European languages, this is still the name of the drug. The term "morphine", used in English and French, was given by the French physicist Joseph Louis Gay-Lussac. A significant contribution to the chemistry of alkaloids in the early years of its development was made by the French researchers Pierre Joseph Pelletier and Joseph Bienaimé Caventou, who discovered quinine (1820) and strychnine (1818). Several other alkaloids were discovered around that time, including xanthine (1817), atropine (1819), caffeine (1820), coniine (1827), nicotine (1828), colchicine (1833), sparteine (1851), and cocaine (1860).
=== Variation === The two lobes differ slightly in size, with the left lobe usually higher than the right. Thymic tissue may be found scattered on or around the gland, and occasionally within the thyroid. The thymus in children stretches variably upwards, at times to as high as the thyroid gland.
Circumcision is near-universal among Jews. The mitzvah of circumcision on the eighth day of life is considered among the most important commandments in Judaism. Barring extraordinary circumstances, failure to undergo the rite is seen by followers of Judaism as leading to a state of Kareth: the extinction of the soul and denial of a share in the world to come. Reasons for biblical circumcision include to show off "patrilineal descent, sexual fertility, male initiation, cleansing of birth impurity, and dedication to God".
==== Hopper cars ==== In 1969, the Northern Pacific Railroad ordered some modified covered hopper cars from American Car and Foundry for transporting perishable food in bulk. The 55-foot (16.76 m)-long cars were blanketed with a layer of insulation, equipped with roof hatches for loading, and had centerflow openings along the bottom for fast discharge. A mechanical refrigeration unit was installed at each end of the car, with sheet-metal ducting forcing cool air into the cargo compartments. The units, rated at 100 short tons (91 t; 89 long tons) capacity (more than twice that of the largest conventional refrigerator car of the day), were economical to load and unload, as no secondary packaging was required. Apples, carrots, onions, and potatoes were transported in this manner with moderate success. Oranges, on the other hand, tended to burst under their own weight, even after wooden baffles were installed to distribute the load better. The Santa Fe Railway leased 100 of the hoppers from ACF, and in April 1972, purchased 100 new units, known as "Conditionaire" cars. The cars' irregular, orange-colored outer surface (though darker than the standard AT&SF yellow-orange used on reefers) tended to collect dirt easily and proved difficult to clean. Santa Fe eventually relegated the cars to more typical, non-refrigerated applications.
=== Biological properties === Despite the promising results in different cell studies and proof of concept studies, there is still incomplete understanding of the full biocompatibility of graphene-based materials. Different cell lines react differently when exposed to graphene, and it has been shown that the lateral size of the graphene flakes, the form and surface chemistry can elicit different biological responses on the same cell line. There are indications that graphene has promise as a useful material for interacting with neural cells; studies on cultured neural cells show limited success. Graphene also has some utility in osteogenesis. Researchers at the Graphene Research Centre at the National University of Singapore (NUS) discovered in 2011 the ability of graphene to accelerate the osteogenic differentiation of human mesenchymal stem cells without the use of biochemical inducers. Graphene can be used in biosensors; in 2015, researchers demonstrated that a graphene-based sensor can be used to detect a cancer risk biomarker. In particular, by using epitaxial graphene on silicon carbide, they were repeatedly able to detect 8-hydroxydeoxyguanosine (8-OHdG), a DNA damage biomarker.
Sources: en.wikipedia.org
Karen M. Frank is an American clinical pathologist and microbiologist researching the pathogenesis of Staphylococcus aureus pneumonia and resistant gram-negative bacteria. She is a senior clinician, principal investigator, and chief of laboratory medicine at the National Institutes of Health Clinical Center.
. It also has historical significance; the Q/m ratio of the electron was successfully calculated by J. J. Thomson in 1897—and more successfully by Dunnington, which involves the angular momentum and deflection due to a perpendicular magnetic field. Thomson's measurement convinced him that cathode rays were particles, which were later identified as electrons, and he is generally credited with their discovery. The CODATA recommended value is −e/me = −1.75882000838(55)×1011 C⋅kg−1. CODATA refers to this as the electron charge-to-mass quotient, but ratio is still commonly used. There are two other common ways of measuring the charge-to-mass ratio of an electron, apart from Thomson and Dunnington's methods.
==== Muscarinic acetylcholine receptor agonist ==== Xanomeline is an agonist that primarily targets the muscarinic acetylcholine receptor family of five muscarinic receptor subtypes, which are designated M1-M5. While it binds with near identical affinity to all five of the muscarinic receptor subtypes as measured by displacement of a muscarinic radioligand, the preponderance of evidence suggests that xanomeline acts preferentially in the central nervous system as a functionally selective partial agonist at the M1 and M4 muscarinic receptors. It has more modest partial agonist pharmacology at the M2, M3 and M5 receptors. In addition to its muscarinic acetylcholine M1 and M4 receptor agonism, xanomeline has been found to act as an antagonist or partial agonist of the M5 receptor.
In the presence of type 2 diabetes, the physician might instead prescribe metformin and thiazolidinediones (rosiglitazone or pioglitazone) as antidiabetic drugs rather than sulfonylurea derivatives. Thiazolidinediones may cause slight weight gain but decrease "pathologic" abdominal fat (visceral fat), and therefore may be prescribed for diabetics with central obesity. Thiazolidinedione has been associated with heart failure and increased cardiovascular risk; so it has been withdrawn from the market in Europe by EMA as of 2010. New clinical guidelines support the use of glucagon-like-peptide-1 receptor agonists, such as semaglutide, for adults with abdominal obesity who have not been able to achieve adequate weight reduction with lifestyle modifications. These medications have largely replaced the use of other anti-diabetic drugs for weight loss. GLP-1 agonists have shown clinically meaningful reductions in body weight and abdominal obesity, and demonstrated improvements in cardiovascular health in randomized trials. For patients unresponsive to lifestyle and medication management of abdominal obesity, metabolic and bariatric surgical options exist. These include sleeve gastrectomy and Roux-en-Y gastric bypass surgery. These surgical options are effective in patients with severe abdominal obesity without significant comorbidities. Surgery leads to substantial reductions in abdominal obesity, waist circumference, and is associated with improvements in type 2 diabetes mellitus, hypertension, and other complications associated with abdominal obesity.
Sources: en.wikipedia.org
HMRC reverses the plan for its self-assessment helpline, announced the previous day, following criticism from the public and MPs. The Senedd approves Vaughan Gething as the next First Minister of Wales. The London Clinic, where the Princess of Wales underwent abdominal surgery, announces that "any breach" of patient confidentiality will be investigated after reports a member of staff tried to access her private records. 21 March The Bank of England leaves interest rates unchanged at 5.25%, for the fifth time in a row. A report published by the Parliamentary and Health Service Ombudsman recommends women born in the 1950s who were affected by the 2010 changes to the state pension age should receive compensation of between £1,000 and £2,900. 22 March Following media speculation about her health, it is revealed that the Princess of Wales has been diagnosed with cancer and is undergoing treatment. Wetherspoons reports an eightfold increase in pre-tax profits during the first six months of the 2023–24 financial year. 23 March – A report compiled by the Resolution Foundation indicates a rise in the number of people leaving work due to long-term health conditions, with the number of people inactive due to long-term health conditions rising from 2.1 million in 2019 to 2.8 million in October 2023, the longest sustained rise since 1994–1998 when records began. The UK is also the only country in the G7 not to return to pre-pandemic employment levels.
In Marfan syndrome, the health of the eye can be affected in many ways, but the principal change is partial lens dislocation, where the lens is shifted out of its normal position. This occurs because of weakness in the ciliary zonules, the connective tissue strands that suspend the lens within the eye. The mutations responsible for Marfan syndrome weaken the zonules and cause them to stretch. The inferior zonules are most frequently stretched, resulting in the lens shifting upwards and outwards, but it can shift in other directions, as well. Nearsightedness (myopia), and blurred vision are common due to connective tissue defects in the eye. Farsightedness can also result particularly if the lens is highly subluxated. Subluxation (partial dislocation) of the lens can be detected clinically in about 60% of people with Marfan syndrome by the use of a slit-lamp biomicroscope. If the lens subluxation is subtle, then imaging with high-resolution ultrasound biomicroscopy might be used. Other signs and symptoms affecting the eye include increased length along an axis of the globe, myopia, corneal flatness, strabismus, exotropia, and esotropia. Those with MFS are also at a high risk for early glaucoma and early cataracts, as well as retinal detachment, the latter one of the reasons that people with Marfan may be advised to avoid contact sports and activities that risk falls.
UDP + procollagen 5-(D-galactosyloxy)-L-lysine Thus, the two substrates of this enzyme are UDP-galactose and procollagen 5-hydroxy-L-lysine, whereas its two products are UDP and procollagen 5-(D-galactosyloxy)-L-lysine.
== Clinical effects == Kynurenine protects the eye by absorbing UV light, especially in the UVA region (315–400 nm). Kynurenine is present in the lens and retina as one of multiple tryptophan derivatives produced in the eye, including 3-hydroxykynurenine, that together provide UV protection and aid in enhancing visual acuity. The use of kynurenine as a UV filter is consistent with its photostability and low photosensitization, owing to its efficient relaxation from the UV-induced excited state. The concentration of this UV filter decreases with age, and this loss of free kynurenine and the concomitant formation of relatively more photosensitizing kynurenine derivatives and kynurenine-protein conjugates may contribute to the formation of cataracts. Evidence suggests that increased kynurenine production may precipitate depressive symptoms associated with interferon treatment for hepatitis C. Cognitive deficits in schizophrenia are associated with imbalances in the enzymes that break down kynurenine. Blood levels of kynurenine are reduced in people with bipolar disorder. Kynurenine production is increased in Alzheimer's disease and cardiovascular disease where its metabolites are associated with cognitive deficits and depressive symptoms. Kynurenine is also associated with tics. Myokines regulate its metabolism. Kynurenine has also been identified as one of two compounds that makes up the pigment that gives the goldenrod crab spider its yellow color.
It begins with an inciting event at the level of the vasculature, probably the endothelium. The inciting event is yet to be elucidated, but may be a viral agent, oxidative stress, or autoimmune. Endothelial cell damage and apoptosis ensue, leading to the vascular leakiness that manifests in early clinical stages as tissue oedema. At this stage, it is predominantly a Th1- and Th17-mediated disease. After this, the vasculature is further compromised by impaired angiogenesis and impaired vasculogenesis (fewer endothelial progenitor cells), likely related to the presence of antiendothelial cell antibodies (AECA). Despite this impaired angiogenesis, elevated levels of pro-angiogenic growth factors such as PDGF and VEGF are often seen in persons with the condition. The balance of vasodilation and vasoconstriction becomes askew, and the net result is vasoconstriction. The damaged endothelium then serves as a point of origin for blood-clot formation and further contributes to ischaemia-reperfusion injury and the generation of reactive oxygen species. These later stages are characterised by Th2 polarity. The damaged endothelium upregulates adhesion molecules and chemokines to attract leucocytes, which enables the development of innate and adaptive immune responses, including loss of tolerance to various oxidised antigens, which includes topoisomerase I. B cells mature into plasma cells, which furthers the autoimmune component of the condition. T cells differentiate into subsets, including Th2 cells, which play a vital role in tissue fibrosis.
Sources: en.wikipedia.org
Semax is based on the ACTH(4-10) fragment, a seven-amino-acid segment of adrenocorticotropic hormone. The synthetic peptide retains the core sequence while removing regions associated with endocrine activity. This modification is intended to isolate effects on the nervous system.
It is registered for clinical use in Russia and a few other countries, typically as a nasal drop formulation. It does not hold approval from the United States Food and Drug Administration or the European Medicines Agency. Outside those markets it is generally handled as a research chemical.
The compound was developed in Moscow and the earliest studies were conducted there, so the primary literature is largely in Russian-language journals. Translation and indexing have been incomplete, which limits access for outside researchers. Independent groups have since published some work, but the total volume remains modest.
Each freeze-thaw cycle can degrade a fraction of the peptide and promote aggregation. Dividing a stock solution into single-use volumes removes repeated cycling as a variable. It also limits the time a thawed solution spends at room temperature.