neurotrophic signaling is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Last reviewed on 2026-03-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
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。
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Analogue of the ACTH(4-10) fragment |
| Amino acid sequence | Met-Glu-His-Phe-Pro-Gly-Pro | Single-letter form MEHFPGP |
| Molecular formula | C37H51N9O10S | Free peptide, nominal mass near 814 Da |
| First registration | 1994, Russia | Nasal formulation for neurological indications |
| Typical purity grade | 95% or higher by HPLC | Research material; higher grades used as reference standards |
Clinical reports describe use in ischaemic stroke, transient ischaemic attack, optic nerve conditions, and cognitive complaints, but most of these studies are small and were conducted in a single region. Systematic reviews have generally described the evidence base as limited in size and variable in methodological quality. Randomised controlled data suitable for international regulatory assessment are scarce. As a result, major treatment guidelines outside Russia do not include the peptide, and interest in it remains largely research-driven rather than routine clinical.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It is described in the literature as an analogue of the ACTH(4–10) fragment, a short N-terminal portion of adrenocorticotropic hormone that retains some neurotropic activity without the full hormonal effects of the parent peptide. The molecule carries a methionine residue at the N-terminus and two proline residues near the C-terminus, features that shape both its interactions with receptor systems and its chemical stability. The free peptide corresponds to the formula C37H51N9O10S and a molecular mass near 813.9 Da.
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.
Proposed mechanisms center on neurotrophic signaling rather than on classical melanocortin receptor activation. Rodent experiments have reported shifts in the expression of brain-derived neurotrophic factor and nerve growth factor after administration, together with changes in the associated receptor systems. Several authors argue that the peptide acts largely through its degradation products and their interaction with peptidergic pathways, but this remains a hypothesis rather than a settled finding. No single molecular target has been identified in a way that the field broadly accepts.
Published research covers ischemic stroke, traumatic brain injury, cognitive impairment, optic nerve conditions and attention-related measures. Much of the human evidence comes from small trials conducted in one country, which limits how far the results generalize. Animal models supply the larger share of the data, and effects seen in rodents do not transfer automatically to people. Reviews have noted that methodological reporting is often incomplete, making it difficult to pool results or compare treatment schedules across studies.
== History == Tom Kudirka, originally from Omaha, Nebraska, and an alumnus of Bellevue West High School, had studied business information systems and electronics before moving to Tulsa to work for Lucent Technologies as a field engineer. Thereafter, he had established multimedia companies, including one dealing with speech recognition. Because Kudirka "thought he was bored", he founded 2015 in Tulsa in May 1997. The name was said to have been chosen for an undisclosed "very significant" reason, although Kudirka later said he did not know what it meant. Kudirka recruited developers he had discovered online and had them relocate to Tulsa. The designer Zied Rieke was the first hire. Through Kudirka's connections with Ritual Entertainment and its CEO, 2015 came to develop Wages of Sin, an expansion pack for Ritual Entertainment's 1998 game Sin. It was released in February 1999. On April 3, 2000, 2015 announced the opening of its Trainwreck Studios division for budget-price games with a wider target audience. The first game therein, Laser Arena, was designed to be playable by Kudirka's three-year-old son and released in September 2000. 2015 was simultaneously working on its third game, Heavy Gear Extreme. The company grew to 15 people, requiring it to expand its office space at 8282 South Memorial Drive. The second Trainwreck Studios game, CIA Operative: Solo Missions, was released in May 2001. 2015 was reported as developing Half-Life: Hostile Takeover as an expansion for Half-Life in November 1999.
=== Reasoning and problem-solving === Early researchers developed algorithms that imitated step-by-step reasoning that humans use when solving puzzles or making logical deductions. By the late 1980s and 1990s, methods were developed for dealing with uncertain or incomplete information, employing concepts from probability and economics. Many of these algorithms were insufficient for solving large reasoning problems because they experienced a "combinatorial explosion", meaning they become exponentially slower as the problems grow. Even humans rarely use the step-by-step deduction that early AI research could model. Humans solve most of their problems using fast, intuitive judgments. Reasoning models, a type of large language model (LLM) trained to generate intermediate chains of thought, emerged in 2024 and allowed improved performance on complex problems in mathematics and coding. These models can produce incorrect outputs or "hallucinations," unlike symbolic reasoning systems.
from the Miocene strata of the Santalla Formation (Spain), representing the first large vertebrate from the El Bierzo Basin reported to date. A study on deciduous teeth and juvenile skulls of members of the genus Chilotherium, providing evidence of utility of dental characters for species discrimination, is published by Kampouridis et al. (2026). Pandolfi, Codrea & Solomon (2026) describe fossil material of a member of the genus Acerorhinus from the Miocene strata from the Crețești 1 site (Romania), with greatest similarity to A. simplex, and refine the species content of the genus Acerorhinus. Titov et al. (2026) describe fossil material of Elasmotherium chaprovicum from the Pleistocene strata from the Taurida Cave (Crimea), including the first upper milk teeth of a member of the genus Elasmotherium reported to date. Ponomarev et al. (2026) report the discovery of fossil material of Stephanorhinus kirchbergensis in the Pleistocene strata from the Komi Republic (Russia), representing the northernmost record of the species in Europe reported to date. Uzunidis & Pandolfi (2026) report evidence of different dynamics of evolution of body mass of the narrow-nosed rhinoceros from Northern Europe and from the Mediterranean, as well as evidence of consistent mixed-feeding strategy in the studied species, with seasonal specialization toward either browsing or grazing in populations near the end of the temporal range of the species.
The peritoneum is the serous membrane forming the lining of the abdominal cavity or coelom in amniotes and some invertebrates, such as annelids. It covers most of the intra-abdominal (or coelomic) organs, and is composed of a layer of mesothelium supported by a thin layer of connective tissue. This peritoneal lining of the cavity supports many of the abdominal organs and serves as a conduit for their blood vessels, lymphatic vessels, and nerves. The abdominal cavity (the space bounded by the vertebrae, abdominal muscles, diaphragm, and pelvic floor) is different from the intraperitoneal space (located within the abdominal cavity but wrapped in peritoneum). The structures within the intraperitoneal space are called "intraperitoneal" (e.g., the stomach and intestines), the structures in the abdominal cavity that are located behind the intraperitoneal space are called "retroperitoneal" (e.g., the kidneys), and those structures below the intraperitoneal space are called "subperitoneal" or "infraperitoneal" (e.g., the bladder).
Muscular dystrophies may be X-linked recessive, autosomal recessive, or autosomal dominant. Diagnosis often involves blood tests and genetic testing. There is no cure for any disorder from the muscular dystrophy group. Several drugs designed to address the root cause are currently available including gene therapy (Elevidys), and antisense drugs (Ataluren, Eteplirsen etc.). Other medications used include glucocorticoids (Deflazacort, Vamorolone); calcium channel blockers (Diltiazem); to slow skeletal and cardiac muscle degeneration, anticonvulsants to control seizures and some muscle activity, and Histone deacetylase inhibitors (Givinostat) to delay damage to dying muscle cells. Physical therapy, braces, and corrective surgery may help with some symptoms while assisted ventilation may be required in those with weakness of breathing muscles. Outcomes depend on the specific type of disorder. Many affected people will eventually become unable to walk and Duchenne muscular dystrophy in particular is associated with shortened life expectancy. Muscular dystrophy was first described in the 1830s by Charles Bell. The word "dystrophy" comes from the Greek dys, meaning "no, un-" and troph- meaning "nourish".
Sources: en.wikipedia.org
Low-carbohydrate diets restrict carbohydrate consumption relative to the average diet. Foods high in carbohydrates (e.g., sugar, bread, pasta) are limited, and replaced with foods containing a higher percentage of fat and protein (e.g., meat, poultry, fish, shellfish, eggs, cheese, nuts, and seeds), as well as low carbohydrate foods (e.g. spinach, kale, chard, collards, and other fibrous vegetables). There is a lack of standardization of how much carbohydrate low-carbohydrate diets must have, and this has complicated research. One definition, from the American Academy of Family Physicians, specifies low-carbohydrate diets as having less than 20% of calories from carbohydrates. There is no good evidence that low-carbohydrate dieting in general confers any particular health benefits apart from weight loss, where low-carbohydrate diets achieve outcomes similar to other diets, as weight loss is mainly determined by calorie restriction and adherence. One particular form of low-carbohydrate diet called the ketogenic diet was first established as a medical diet for treating epilepsy. It became a popular diet for weight loss through celebrity endorsement, but there is no evidence of any distinctive benefit for this purpose and the diet carries a risk of adverse effects, with the British Dietetic Association naming it one of the "top five worst celeb diets to avoid" in 2018.
Xanthoria parietina serves as both a food source and shelter for certain gastropods. The snail Balea perversa uses the lichen for shelter and nourishment. Similarly, other gastropods, such as Helicigona lapicida, feed on Xanthoria parietina. This grazing may contribute to lichen dispersal: photobiont cells from X. parietina partially survive passage through the snail's digestive tract, retaining some photosynthetic activity even after digestion. Such survival raises the possibility that snail herbivory could facilitate lichen relichenization—either by recombining surviving symbionts from the same thallus or by mixing photobionts and mycobionts from different individuals in fecal deposits. However, digestion significantly reduces photobiont viability, with photobiont fluorescence (a measure of photosynthetic activity) declining by 41–44% after passage through the snail gut. While some cells remain intact, they often suffer morphological damage (including shrunken chloroplasts and enlarged cell wall-to-membrane distances), leaving it unclear whether surviving photobionts can effectively establish new lichens without viable fungal spores or hyphae.
=== Companies === To translate his discoveries into therapeutics, Verdine has founded or co-founded numerous public biotech companies including Variagenics, Enanta, Eleven Bio, Tokai, Wave Life Sciences, and Aileron. He also founded the private company Gloucester Pharmaceuticals, which was acquired by Celgene in 2009. His companies share the mission of developing molecules intended to target “hard-to-drug” endogenous targets that have remained out of reach of modern cell-penetration technologies.
== References == Charpin, Dominique (2010). Writing, Law, and Kingship in Old Babylonian Mesopotamia. University of Chicago Press. ISBN 978-0-226-10159-0. Charpin, Dominique (2023). "Old Babylonian Law and Justice according to Letters and Legal Documents". In Démare-Lafont, Sophie; Fleming, Daniel E. (eds.). Judicial Decisions in the Ancient Near East. SBL Press. pp. 103–222. doi:10.2307/jj.8784672. ISBN 978-1-62837-486-5. Harris, Rivkah (1969). "Notes on the Babylonian Cloister and Hearth: A Review Article". Orientalia. 38 (1): 133–145. ISSN 0030-5367. JSTOR 43079057. Harris, Rivkah (1976). "On Kinship and Inheritance in Old Babylonian Sippar". Iraq. 38 (2): 129–132. doi:10.2307/4200036. ISSN 0021-0889. Jacquet, Antoine (2013). "Family Archives in Mesopotamia during the Old Babylonian Period". In Faraguna, Michele (ed.). Archives and archival documents in ancient societies: Legal Documents in Ancient Societies IV: Trieste 30 September-1 October 2011. Edizioni Università di Trieste. pp. 63–85. ISBN 978-88-8303-460-2. De Graef, Katrien (2016). "Cherchez la femme! The Economic Role of Women in Old Babylonian Sippar". In Lion, Brigitte; Michel, Cécile (eds.). The Role of Women in Work and Society in the Ancient Near East. De Gruyter. pp. 270–295. doi:10.1515/9781614519089-016. ISBN 978-1-61451-908-9.
Sources: en.wikipedia.org
Registered medical products are most often 0.1% nasal drops. Research suppliers ship lyophilized powder, usually in milligram quantities, which is dissolved before use. The active peptide is the same in both cases; presentation and excipients differ.
No. The peptide is synthetic, although it is modelled on a fragment of a naturally occurring hormone. ACTH(4-10) is generated when ACTH is cleaved, but the Pro-Gly-Pro extension is not a known endogenous sequence. It is therefore a designed analogue rather than a natural metabolite.
The label reflects reported effects on attention, memory and recovery after neurological injury in regional clinical reports. Those reports are mostly small and have not been widely replicated outside the region. The classification is descriptive and does not imply a single defined mechanism.
电喷雾或基质辅助激光解吸电离质谱是常用手段，测得的质子化离子质荷比可换算为分子量。结果与理论值落在合理误差内，才支持结构一致的判断。