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 2025-11-09. Numbers and descriptions here follow the published literature rather than marketing material.
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.
Published studies are dominated by animal models of stroke, ischemia, and cognitive impairment, with a smaller number of human trials conducted in Russia. Many of the human reports are small, single-center, and published in Russian-language journals, which limits independent scrutiny. Outcome measures vary between studies and often rely on clinician-rated scales rather than objective biomarkers. Systematic reviews have noted the methodological weaknesses and called for larger, preregistered trials before firm conclusions can be drawn.
Claims about enhanced focus, memory, or mood in healthy people rest mostly on anecdotal reports and community discussion rather than on controlled data. It remains unclear whether any cognitive benefit observed in patients recovering from brain injury would extend to uninjured users. Dose-response relationships, long-term safety, and interactions with other drugs are not well characterized in the peer-reviewed literature. Questions about optimal route of administration and treatment duration likewise remain open.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Contains one methionine sulfur atom |
| Molecular mass | Approximately 814 Da | Consistent with a seven-residue peptide |
| Appearance | White to off-white powder | Typical lyophilized form |
| Solubility | Freely soluble in water | Also soluble in dimethyl sulfoxide |
| Typical storage | -20 °C, desiccated | Limits methionine oxidation |
Clinical evidence consists largely of small trials with modest sample sizes, often without independent replication. Reported endpoints include cognitive scores, recovery after stroke, and visual function, but study designs vary widely and few trials meet contemporary reporting standards. Systematic reviewers have noted a high risk of bias in several of these reports. No large multicenter trial conducted outside Russia has been published. The compound is therefore best described as investigational in most jurisdictions, with its clinical role still unresolved.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its chain combines the first seven residues of corticotropin with a C-terminal proline-glycine-proline extension, a modification intended to slow enzymatic breakdown. The free peptide has a molecular mass near 813.9 daltons. It belongs to the class of ACTH-derived fragments studied for central nervous system activity rather than for adrenal steroid stimulation. This structural relationship to a natural hormone fragment is the usual starting point for describing the compound in the literature.
Development took place during the 1980s at institutes of the Russian Academy of Sciences, where peptide fragments of ACTH were screened for cognitive and neuroprotective effects. The compound received regulatory approval in Russia as a nasal preparation, marketed for conditions such as ischemic stroke, transient ischemic attacks, and optic nerve disorders. Registration in other countries has not followed. Most published clinical reports originate from a small number of Russian research groups, and independent replication outside that setting remains limited. The regulatory status therefore differs sharply between Russia and the rest of the world.
纯度评估以反相高效液相色谱为主，通过主峰面积百分比给出粗略结果，再配合电喷雾质谱核对分子量。氨基酸分析可验证组成比例，手性色谱或毛细管电泳用于检查残基构型。常见杂质包括缺失序列的短肽、氧化产物与二聚体。由于多数市售品不附带完整检验报告，独立第三方检测常被用来核实标称值。
从分子层面看，Semax 是线性七肽，没有二硫键、糖基或脂链修饰，N 端为游离氨基，C 端为游离羧基。分子含组氨酸与谷氨酸侧链，因此在水和甲醇等极性溶剂中溶解良好，在非极性溶剂中溶解有限。计算分子量约为 814 Da，与其质子化离子的质荷比吻合，可用于质谱确认。
Terminology around the compound varies by source. It appears in catalogues and papers as Semax, as the heptapeptide ACTH(4-7)-Pro-Gly-Pro, and under various alphanumeric laboratory codes used by individual suppliers. These names refer to the same sequence but may imply different salt forms, purity grades, or counter-ions. Peptide databases usually list the free base mass, while product descriptions sometimes report acetate or trifluoroacetate salts with a different formula weight. Because naming conventions for research peptides are not standardised across vendors, checking the declared sequence and measured mass is more reliable than relying on a trade name alone.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its design combines the ACTH(4-7) core fragment with a C-terminal Pro-Gly-Pro extension, a modification intended to improve stability and prolong activity. The molecule is hydrophilic, carries no lipid chains or glycosylation, and has a theoretical mass just over 810 daltons in its free form. All seven residues are proteinogenic amino acids, so no non-natural building blocks appear in the backbone. A free N-terminal methionine and C-terminal proline define the unmodified parent peptide.
The compound was developed during the 1980s at the Institute of Molecular Genetics in Moscow as part of research on fragments of adrenocorticotropic hormone. Early work examined short ACTH-derived sequences that retained neurotrophic effects while lacking the endocrine activity of the full hormone. Semax entered clinical use in Russia during the 1990s, where it received registration for several neurological indications. Outside that region it remained primarily a laboratory research material rather than an approved therapeutic. English-language literature on it grew more slowly and frequently cited the original Russian studies.
=== In development === Several new drugs and treatments are under development for snakebite. For instance, the metal chelator dimercaprol has recently been shown to potently antagonize the activity of Zn2+-dependent snake venom metalloproteinases in vitro. New monoclonal antibodies, polymer gels and a small molecule inhibitor called Varespladib are in development. A core outcome set (minimal list of consensus outcomes that should be used in future intervention research) for snakebite in South Asia is being developed. In an article published in Nature in October 2025, a group led by researchers from the Technical University of Denmark has presented the possibility of a broad-spectrum antivenom that can work against the bites of many different snakes. They have developed an experimental polyvalent recombinant anti-venom that the authors claim to be capable of neutralising seven toxin families or subfamilies. A study conducted by Jacob Glanville used two antibodies taken from the memory B cells of blood from a "hyperimmune" donor, who had been deliberately bitten by many species of snake, to develop an antivenom "cocktail". Elapidae were the focus of the study, of which nineteen are classified as being the deadliest on Earth by the World Health Organization. Tested on mice, the antivenom cocktail prevented death from thirteen of the nineteen species, with partial protection observed from the other six.
== Clinical significance == The extracellular ADP-ribosyl-transferase ART2 is expressed only on T cells. T cell activation of P2X7 receptors can activate the T cells or cause T cell differentiation, can affect T cell migration or (at high extracellular levels of NAD+) can induce cell death by ART2.
Portugal's legislative body is the Assembly of the Republic, a unicameral parliament. It consists of a single chamber with a minimum of 180 seats and a maximum of 230, elected by popular vote every four years or when dissolved. The members of parliament represent the whole country and not the constituencies for which they are elected. The Assembly of the Republic is dominated by three political parties, the Social Democratic Party (PSD), Chega (CH), and the Socialist Party (PS). As the head of government, the prime minister directs government policy, leads the Council of Ministers which includes ministers and junior ministers that execute government policy, and is appointed by the president in light of electoral results after consulting with the parties with parliament seats. Portugal's current prime minister is Luís Montenegro, who took office after the AD – PSD/CDS Coalition won enough seats to form a minority government following the 2024 Portuguese legislative election. Portugal has a civil law system based on Roman law and on Canon Law and influenced by German civil law. The Constitution is the supreme law of Portugal. In the Portuguese legal system, private civil law and criminal law are codified in the Código Civil and the Código Penal respectively. Portugal's court system is organised into judicial, administrative, and fiscal branches with three levels of jurisdiction and separate courts of last appeal, while the Constitutional Court is responsible for constitutional review and oversight of elections, referendums and political parties.
The lily family, Liliaceae, consists of about 15 genera and 610 species of flowering plants within the order Liliales. They are monocotyledonous, perennial, herbaceous geophytes, often growing from bulbs although some have rhizomes. The leaves are linear in shape, with their veins usually arranged parallel to the edges, single and arranged alternating on the stem, or in a rosette at the base. The flowers are large with six colored or patterned petaloid tepals (undifferentiated petals and sepals) arranged in two whorls of three, six stamens and a superior ovary. The fruit can be a berry or capsule, with seeds dispersed by animals or wind, respectively. First described in 1789, the lily family became a paraphyletic "catch-all" (wastebasket) group of lilioid monocots that did not fit into other families and included many genera now included in other families (and in some cases in other orders). Consequently, treatments of "Liliaceae" often include these other taxa. The family likely evolved between 82 and 52 million years ago during the Late Cretaceous to Early Paleogene periods. Plants in this family have evolved with a fair amount of morphological diversity despite their genetic similarity. Liliaceae are widely distributed, mainly in temperate regions of the Northern Hemisphere and the flowers are insect pollinated. Most of their genera, Lilium in particular, face considerable herbivory pressure from deer in some areas, both wild and domestic.
Sources: en.wikipedia.org
The intent was to identify donors potentially infected with hepatitis C because no specific test for that disease was available at the time. Prior to July 1992, widespread blood donation testing in the US for hepatitis C was not carried out by major blood banks. With the introduction of second-generation ELISA antibody tests for hepatitis C, the Red Cross changed the ALT policy. As of July 2003, donors previously disqualified for elevated ALT levels and no other reason may be reinstated as donors when they contact the donor-counseling department of their regional Red Cross organization. In 2000, the American Association for Clinical Chemistry determined that the appropriate terminology for AST and ALT are aspartate aminotransferase and alanine aminotransferase. The term transaminase is outdated and no longer used in liver disease.
Cyberwarfare is the use of cyberattacks against an enemy state, causing comparable harm to traditional warfare. Some intended outcomes could be espionage, sabotage, propaganda, manipulation, or economic warfare. Many countries, including the United States, United Kingdom, Russia, China, Israel, Iran, India, and North Korea, have active cyber capabilities for offensive and defensive operations. As states explore the use of cyber operations and combine capabilities, the likelihood of physical confrontation and violence playing out as a result of, or part of, a cyber operation is increased. However, meeting the scale and protracted nature of war is unlikely, thus ambiguity remains. There has been significant debate among experts regarding the definition of cyberwarfare, and even if such a thing exists. One view is that the term is a misnomer, since no cyberattack to date could be described as a war. An alternative view is that it is a suitable label for cyberattacks that cause physical damage to people and objects in the real world. The first instance of kinetic military action used in response to a cyberattack resulting in the loss of human life was observed on 5 May 2019, when the Israel Defense Forces targeted and destroyed a building associated with an ongoing cyberattack.
=== Bu === John Buchanan (1917–2007). American biochemist at MIT, best known for his research on the biosynthesis of purines. Member Natl. Acad. Sci. USA. Eduard Buchner (1860–1917). German chemist and physiologist at LMU Munich, who overthrew the doctrine of vitalism by showing that cell-free yeast extract could catalyse fermentation, a discovery described by Arthur Kornberg as the beginning of biochemistry. 1907 Nobel Prize in Chemistry. Dean Burk (1904–1988). American biochemist at the Fixed Nitrogen Research Laboratory, co-discoverer of biotin. He is credited (with Hans Lineweaver) with introducing the double-reciprocal plot in kinetics. He became a vociferous opponent of water fluoridation. Robert H. Burris (1914–2010). American biochemist at the University of Wisconsin–Madison, expert on nitrogen fixation. Member Natl. Acad. Sci. USA. Stephen Busby (DPhil 1975) FRS, biochemist at the University of Birmingham. Carlos Bustamante (b. 1951). Peruvian-American biophysicist at UC Berkeley. Known for single-molecule studies, including the use of optical tweezers for measuring the forces that maintain biological structures. Member Natl. Acad. Sci. USA.
== Ethics == Ethical issues with bioarchaeology revolve around the treatment and respect for the dead. Large-scale skeletal collections were first amassed in the US in the 19th century, largely the remains of Native Americans. No permission was granted by surviving family for study and display. Federal laws such as 1990's NAGPRA (Native American Graves Protection and Repatriation Act) allowed Native Americans to regain control over their ancestors' remains and associated artifacts. Many archaeologists did not realize that many people perceive archaeologists as non-productive and/or grave robbers. Concerns about mistreatment of remains are not unfounded: in a 1971 Minnesota excavation, White and Native American remains were treated differently; Whites were reburied, while Native Americans were moved to a natural history museum. African American bioarchaeology grew after NAGPRA and its effect of ending the study of Native American remains. Bioarchaeology in Europe was not as disrupted by repatriation issues. However, because much of European archaeology has been focused on classical roots, artifacts and art have been emphasized and Roman and post-Roman skeletal remains were nearly completely neglected until the 1980s. In prehistoric European archaeology, biological remains began to be analyzed earlier than in classical archaeology.
=== Asia === In Western Asia, during the region's November–April rainy season, there is increased precipitation in the El Niño phase and reduced precipitation in the La Niña phase on average. During El Niño years: As warm water spreads from the west Pacific and the Indian Ocean to the east Pacific, it takes the rain with it, causing extensive drought in the western Pacific and rainfall in the normally dry eastern Pacific. Singapore experienced the driest February in 2010 since records began in 1869, with only 6.3 mm of rain falling in the month. The years 1968 and 2005 had the next driest Februaries, when 8.4 mm of rain fell. During La Niña years, the formation of tropical cyclones, along with the subtropical ridge position, shifts westward across the western Pacific Ocean, which increases the landfall threat in China. In March 2008, La Niña caused a drop in sea surface temperatures over Southeast Asia by 2 °C (3.6 °F). It also caused heavy rains over the Philippines, Indonesia, and Malaysia.
Sources: en.wikipedia.org
Bactericidal permeability-increasing protein (BPI) is a 456-residue (~50kDa) protein that is part of the innate immune system, coded for in the human by the BPI gene. It belongs to the family of lipid-binding serum glycoproteins. BPI was initially identified in neutrophils, but is found in other tissues including the epithelial lining of mucous membranes. It is an endogenous antibiotic protein with potent killing activity against Gram-negative bacteria. It binds to compounds called lipopolysaccharides produced by Gram-negative bacteria. Lipolysaccharides are potent activators of the immune system; however, BPI at certain concentrations can prevent this activation. BPI was discovered by Jerrold Weiss and Peter Elsbach at New York University Medical School.
Methods have been developed to purify DNA from organisms, such as phenol-chloroform extraction, and to manipulate it in the laboratory, such as restriction digests and the polymerase chain reaction. Modern biology and biochemistry make intensive use of these techniques in recombinant DNA technology. Recombinant DNA is a man-made DNA sequence that has been assembled from other DNA sequences. They can be transformed into organisms in the form of plasmids or in the appropriate format, by using a viral vector. The genetically modified organisms produced can be used to produce products such as recombinant proteins, used in medical research, or be grown in agriculture.
Carbon (6C) has 14 known isotopes, from 8C to 20C as well as 22C, of which only 12C and 13C are stable. The longest-lived radioisotope is 14C, with a half-life of 5700 years. This is also the only carbon radioisotope found in nature, as trace quantities are formed cosmogenically by the reaction 14N + n → 14C + 1H. The most stable artificial radioisotope is 11C, which has a half-life of 20.34 minutes. All other radioisotopes have half-lives under 20 seconds, most less than 200 milliseconds. Lighter isotopes exhibit beta-plus decay into isotopes of boron and heavier ones beta-minus decay into isotopes of nitrogen, though at the limits particle emission occurs as well. The two lightest isotopes decay into helium via short-lived isotopes of lithium, beryllium and boron.
=== Other uses === Health benefits for CBD beyond its approved medical uses are unproven; there are potential risks like liver damage and drug interactions if used during pregnancy or breastfeeding. CBD may help with pain, sleep, and addiction, potentially serving as a non-intoxicating alternative to opioids, but clinical evidence is limited and legal regulations are complex. There is very limited evidence on CBD use in mental disorders, and current studies do not show clear benefits for treating any mental illness or disorder. CBD is strongly advised against during pregnancy or breastfeeding due to unknown effects on fetal and infant development.
Topography is the study of forms and features of land surfaces. The topography of an area may refer to landforms and features themselves, or a description or depiction in maps. Topography is a field of geoscience and planetary science, and is concerned with local detail in general, including not only relief, but also natural, artificial, and cultural features such as roads, land boundaries, and buildings. In the United States, topography often means specifically relief, even though the USGS topographic maps record not just elevation contours, but also roads, populated places, structures, land boundaries, and so on. Topography in a narrow sense involves the recording of relief or terrain, the three-dimensional quality of the surface, and the identification of specific landforms; this is also known as geomorphometry. In modern usage, this involves the generation of elevation data in digital form (DEM). It is often considered to include the graphic representation of the landform on a map by a variety of cartographic relief depiction techniques, including contour lines, hypsometric tints, and relief shading.
Sources: en.wikipedia.org
It is registered as a pharmaceutical product in Russia, where it is typically supplied as a nasal solution. In most other countries it is not an approved drug and is traded as a research chemical instead. Approval status depends entirely on the jurisdiction involved.
Most published work uses intranasal administration, matching the route of the registered Russian formulation. Some animal experiments use intravenous or intraperitoneal injection. The route matters because the intact peptide is cleared rapidly from blood, so exposure differs between methods.
A purity value describes the share of the powder accounted for by the target peptide, usually by high-performance liquid chromatography. It does not confirm that the sequence is correct, which requires mass spectrometry or amino acid analysis. Purity and identity are separate checks.
It is associated with the melanocortin receptor family, particularly subtypes found in the central nervous system. This interaction is separate from the adrenal pathway activated by full-length ACTH.