semax 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.
Updated 2025-11-16. Numbers and descriptions here follow the published literature rather than marketing material.
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. The first four residues correspond to the ACTH(4-10) fragment, while the terminal Pro-Gly-Pro extension was added to improve metabolic stability. Its molecular formula is C37H51N9O10S and its monoisotopic mass is approximately 813.9 Da. The compound is classified as a peptide research chemical and as a registered pharmaceutical product in Russia, but it does not hold marketing approval in the European Union or the United States. Naming conventions vary across supplier catalogs.
Development of the compound took place in the Soviet Union during the 1980s, largely through peptide research groups affiliated with the Shemyakin-Ovchinnikov Institute and Moscow State University. Investigators screened fragments of adrenocorticotropic hormone for activity on the central nervous system while attempting to separate cognitive effects from hormonal ones. The shortened sequence was selected because it retained behavioral activity in animal models without stimulating corticosteroid release. Early publications described the molecule as an ACTH(4-10) analog.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Seven-residue peptide |
| Molecular mass | 813.9 Da | Monoisotopic value |
| Appearance | White to off-white powder | Lyophilized form |
| Solubility | Freely soluble in water | Also soluble in saline and polar solvents |
| Storage (dry) | -20 °C or lower | Desiccated, protected from light |
研究兴趣主要集中在神经营养因子相关的路径上，包括脑源性神经营养因子与神经生长因子的表达变化。部分实验报告称在特定条件下观察到这些因子的水平上升，但具体信号通路和剂量依赖关系仍未完全厘清。多数公开数据来自细胞模型和动物实验，人体对照研究数量有限。因此，该化合物的作用机制在文献中属于活跃讨论，而非已经确立的定论。
Semax 是一种人工合成的七肽，氨基酸序列为 Met-Glu-His-Phe-Pro-Gly-Pro，单字母缩写记作 MEHFPGP。它被归类为促肾上腺皮质激素片段 ACTH(4-10) 的结构类似物，但并不天然存在于生物体内。母体片段 ACTH(4-10) 的序列为 Met-Glu-His-Phe-Arg-Trp-Gly，Semax 替换了中间两个残基，并在羧基端延长了 Pro-Gly-Pro 三肽。这种延长被普遍认为能提升分子对肽酶的耐受性。
该化合物于二十世纪八十年代在俄罗斯被开发，相关工作由俄罗斯科学院分子遗传学研究所的研究团队主导。开发目标并非复制 ACTH 的完整激素活性，而是寻找保留其神经作用方向、同时去除促肾上腺皮质激素释放效应的短肽片段。研究记录显示，这一方向促成了多个相关短肽的合成与筛选，而 Semax 是其中被研究最广泛的一个。当地文献常以 Семакс 这一名称指代它。
稳定性主要由水解与氧化两条路径支配。肽键在中性或弱酸性条件下相对稳定，遇到强碱或长时间高温则明显断裂；甲硫氨酸侧链容易被氧化成亚砜，使主峰前移并拉低实际含量。金属离子、光照和反复冻融会进一步促进降解或聚集。冻干粉在低温避光条件下可存放较长时间，配制后的水溶液通常需要冷藏并尽快用完。
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。
Chemoreceptor A sensory receptor that responds to chemical stimuli, such as taste molecules or blood oxygen levels. Located in tissues including the tongue, nasal cavity, and blood vessels. Cholinergic Refers to cells or systems that use acetylcholine as a neurotransmitter. Cholinergic neurons are involved in memory, attention, and muscle activation. Choroid plexus A network of cells located in the ventricles of the brain that produces cerebrospinal fluid and contributes to the maintenance of the blood–CSF barrier. Chromatolysis A cellular response to neuronal injury, characterized by swelling of the cell body and dispersal of Nissl substance, indicating a disruption in protein synthesis. Cingulate cortex A part of the limbic system located on the medial side of the cerebral hemispheres. It is involved in emotion formation, pain perception, decision-making, and cognitive control. Cognition The set of mental processes involved in acquiring knowledge and understanding through thought, experience, and the senses. Includes attention, memory, language, and problem-solving. Cognitive neuroscience A field that studies the biological processes underlying cognition, focusing on how brain structure and function give rise to mental activities. Commissure A bundle of nerve fibers that connects corresponding areas between the two hemispheres of the brain. The largest is the corpus callosum. Conditioned stimulus In classical conditioning, a previously neutral stimulus that, after being paired with an unconditioned stimulus, elicits a learned response.
His crimes, which targeted around 3,500 children across 30 countries, are described by Mr Justice O'Hara as ones of "sadism and depravity" which "scarred" the childhoods of his victims. Appearing at the Old Bailey, Dylan Earl pleads guilty to carrying out an arson attack on a Ukrainian-owned business in east London on behalf of Russia. A Scottish couple are given permission to proceed with a legal case that will attempt to overturn the scrapping of universal winter fuel payments for pensioners. 27 October – Labour MP Mike Amesbury is suspended from the party and has the whip withdrawn, after CCTV footage emerges appearing to show him punching a man to the ground. 28 October Far-right activist Tommy Robinson is sentenced to 18 months in prison for contempt of court for repeating false allegations against a Syrian refugee, in breach of an injunction. Manchester United sack manager Erik ten Hag less than 24 hours after a 2–1 defeat to West Ham United, leaving the club in 14th place after nine games. Assistant Ruud van Nistelrooy takes charge on an interim basis until a permanent replacement is found. 30 October October 2024 United Kingdom budget: Rachel Reeves unveils her first budget as chancellor, which includes £40bn in tax rises, intended to offset what she alleges is a £22bn "black hole" in the nation's finances, while enabling the largest hike in NHS funding since 2010. The first case of Clade Ib mpox, a more spreadable variant linked to the outbreak in Africa, is detected in the UK.
Diagnostic criteria of MFS were agreed upon internationally in 1996. However, Marfan syndrome is often difficult to diagnose in children, as they typically do not show symptoms until reaching pubescence. A diagnosis is based on family history and a combination of major and minor indicators of the disorder, rare in the general population, that occur in one individual – for example: four skeletal signs with one or more signs in another body system such as ocular and cardiovascular in one individual. The following conditions may result from MFS, but may also occur in people without any known underlying disorder.
== Practice == In the practice of chemistry, pure chemistry is the study of the fundamental principles of chemistry, while applied chemistry applies that knowledge to develop technology and solve real-world problems.
Sources: en.wikipedia.org
Congenital tracheomalacia often improves without specific intervention; when required, interventions may include beta agonists and muscarinic agonists, which enhance the tone of the smooth muscle surrounding the trachea; positive pressure ventilation, or surgery, which may include the placement of a stent, or the removal of the affected part of the trachea. In dogs, particularly miniature dogs and toy dogs, tracheomalacia, as well as bronchomalacia, can lead to tracheal collapse, which often presents with a honking goose-like cough.
== History == Gepirone was developed by Bristol-Myers Squibb in 1986, but was out-licensed to Fabre-Kramer in 1993. The FDA rejected approval for gepirone in 2002 and 2004. It was submitted for the preregistration (NDA) phase again in May 2007 after adding additional information from clinical trials as the FDA required in 2009. However, in 2012 it once again failed to convince the FDA of its qualities for treating anxiety and depression. In December 2015, the FDA once again gave gepirone a negative review for depression due to concerns of efficacy. However, in March 2016, the FDA reversed its decision and gave gepirone ER a positive review. Gepirone ER was finally approved for the treatment of major depressive disorder in the United States in September 2023. A 2026 scientific paper discussed the FDA's decision process and cricitised the approval and subsequent labeling of the drug.
== Personal life == Since his playing career ended, Bagwell has spent much of his time with his family while sporadically taking coaching and special assignment positions for the Astros. He is married to Rachel Bagwell, his third wife, with whom he has five children in a blended family. Rachel had three children prior to meeting Jeff. Before his marriage to Rachel, Jeff had two daughters, Blake and Bryce. Bagwell married his first wife, model Shaune Bagwell (née Stauffer), in 1992. He later married Ericka Bagwell, with whom he had his two daughters. Rachel Bagwell was the widow of Greater Houston-area hand surgeon Dr. Michael Brown, the owner and founder of Brown Hand Center. In spite of his professional success, Bagwell has stated that he "doesn't enjoy too much of the spotlight" that follows. While giving a tribute to him during the retirement ceremony of his uniform number, longtime friend and former teammate Brad Ausmus noted several little-known facts. "He liked soccer as much as ... baseball" while growing up in Connecticut. He hit three fewer home runs than his boyhood idol, Carl Yastrzemski, who hit 452. "His baseball card says he's six feet tall. He's closer to 5' 10"." Both Bagwell and Ausmus hit 32 triples in their careers. After his playing career, Bagwell was seen with significantly longer hair. Remarked Ausmus, "I want to confirm he does not have hair extensions." In January 2015, Bagwell reportedly sold his home in the Memorial neighborhood of Houston.
2023, Overseas Fellow of the Australian Academy of Technological Sciences and Engineering (FTSE) 2019, Othmer Gold Medal, Science History Institute and others 2018, honorary Doctorate, Utrecht University 2017, Catalyst Award, Science Club for Girls 2015, Heinz Award, Heinz Family Foundation, in the Technology, the Economy and Employment category "for her seminal work in tissue engineering and disease detection, including the cultivation of functional liver cells outside of the human body, and for her passion in promoting the advancement of women in the STEM fields." 2014, Lemelson-MIT Prize, Massachusetts Institute of Technology "for her dedication to the next generation of scientists, and groundbreaking inventions to improve human health and patient care on a global scale." 2011, BEAM (Brown Engineering Alumni Medal) Award, Brown University School of Engineering 2008, Howard Hughes Medical Institute investigator 1999, Packard Fellowship, David and Lucile Packard Foundation
=== Pharmacokinetics === The bioavailability of tianeptine is approximately 99%. Its plasma protein binding is about 95%. The metabolism of tianeptine is hepatic, via β-oxidation. CYP enzymes are not involved, which limits the potential for drug-drug interactions. Maximal concentration is reached in about an hour and the elimination half-life is 2.5 to 3 hours. The elimination half-life has been found to be increased to 4 to 9 hours in the elderly. Tianeptine is usually packaged as a sodium salt but can also be found as tianeptine sulfate, a slower-releasing formulation patented by Janssen in 2012. In 2022 Tonix Pharmaceuticals received permission from the US FDA to conduct phase II clinical trials on tianeptine hemioxalate extended-release tablets designed for once-daily use. The project was discontinued in late 2023 because of disappointing results in clinical trials. Tianeptine has two active metabolites, MC5 (a pentanoic acid derivative of the parent compound) and MC3 (a propionic acid derivative). MC5 has a longer elimination half-life of approximately 7.6 hours, and takes about a week to reach steady-state concentration under daily-dosing. MC5 is a mu-opioid agonist but not delta-opioid agonist, with EC50 at the mu-opioid receptor of 0.545 μM (vs 0.194 μM for tianeptine). MC3 is a very weak mu-opioid agonist, with an EC50 of 16 μM. Tianeptine is excreted 65% in the urine and 15% in feces.
Sources: en.wikipedia.org
Both sides agreed to build a "constructive strategic and stable relationship between China and the United States based on respect, fairness, and equality." Both sides agreed to support each other in successfully hosting the APEC Leaders' Informal Meeting and the G20 Leaders' Summit. The two heads of state expressed their intention to attend the meetings hosted by the other. The two heads of state agreed that Iran should uphold its commitment not to develop nuclear weapons and that no country or organization should impose tolls on international waterways. The two heads of state recalled that China and the United States were allies in World War II and fought side by side to win the war. The two heads of state acknowledged the positive role of the China–US trade consultation mechanism and the results of the consultations between the two trade teams, including the establishment and advancement of mechanisms such as the Council of Trade, the reaching of a $30 billion reciprocal tariff reduction arrangement, and the extension of the Kuala Lumpur trade consultation results, and instructed that these be implemented. Cooperation between Chinese and American drug enforcement agencies has yielded visible results. Recently, the two sides have worked closely together to crack multiple cases involving new psychoactive substances and precursor chemicals, arresting dozens of suspects in both countries. Both sides agreed to establish a China-US artificial intelligence dialogue to exchange views on the risks and benefits of AI. The next dialogue will be held in November this year.
== Method principle == Before the introduction of the first automated cell counters, hematologists were referred to manual cell count under the microscope. The Celloscope method for automated counting of blood cells was described in an article by Öhlin in 1958. In the described method, cells in a saline (conductive) solution are allowed to pass through a capillary with a length and diameter corresponding to the size of blood cells. At the same time, an electric current passes the capillary, and each cell then gives rise to an electric pulse through the increase in resistance that it causes in the electric circuit. The number of pulses is recorded and corresponds to the number of cells in a certain volume. Diluting the blood sample to a sufficient extent for the distance between the cells when passing through the capillary to be greater than the dimension of the cells and capillary ensures that each cell is counted individually. As cells are counted in an absolute volume of the suspension, the number of cells in mm3 of whole blood can be calculated using the dilution factor. The described automated Celloscope cell count method enabled an improved accuracy compared with manual examination by microscopy, while decreasing manual work for the operator. The method allows 50 000 cells to be counted in about 45 seconds, with high accuracy. The Celloscope counter was also equipped with a discriminator, or electrical threshold, which allows only pulses above a certain size to be counted, enabling different blood cells to be counted.
Erinacines are natural substances isolated from the mycelium of Hericium erinaceus (lion's mane mushroom). They belong to the group of cyathin diterpenoids (erinacines A–K, P, Q, S, U) and are subjects of pharmacological research, which largely focuses on the benefits of erinacine on the brain. All erinacines are able to readily cross the blood–brain barrier in vivo, which largely influences the bioavailability of the compounds in the brain.
In transgender women, breast development is a desired effect of antiandrogen and/or estrogen treatment. Bicalutamide induces breast development in individuals assigned male at birth by two mechanisms: 1) blocking androgen signaling in breast tissue; and 2) increasing estrogen levels. Estrogen is responsible for the induction of breast development under normal circumstances, while androgens powerfully suppress estrogen-induced breast growth. It has been found that very low levels of estrogen can induce breast development in the presence of low or no androgen signaling. In accordance, not only does bicalutamide induce gynecomastia at a high rate when given as a monotherapy to men with prostate cancer (38–85%; 66% in one very large trial), similarly to high-dose estrogen therapy with diethylstilbestrol (41–77%), NSAAs have been found to result in a higher incidence of gynecomastia in combination with a GnRH analogue (13–25%) relative to GnRH analogue therapy or castration alone (1–16%) (in spite of the presence of only castrate levels of estrogen in both cases). The rate of gynecomastia with CAB is also higher than with CPA monotherapy (7%). A study of men treated with NSAA (flutamide or bicalutamide) monotherapy for prostate cancer found that NSAAs induced full ductal development and moderate lobuloalveolar development of the breasts from a histological standpoint.
Sources: en.wikipedia.org
It is a synthetic peptide of seven amino acids. Its backbone corresponds to a fragment of adrenocorticotropic hormone extended at the carboxyl end. The material is distributed as a lyophilized solid for laboratory use.
The extension was introduced to slow enzymatic breakdown of the peptide in biological systems. Natural ACTH fragments are degraded rapidly by peptidases. Adding the tripeptide was intended to extend the window during which the molecule remains intact.
Most published work consists of animal experiments conducted in a small number of laboratories. Human data are limited in number and size. Whether the observed effects translate into reliable clinical benefit is still unresolved.
Reversed-phase HPLC gives the main purity figure, most often with UV detection near 214 nanometres. Mass spectrometry then confirms the molecular mass. Together the two methods distinguish a correct sequence from a closely related impurity.