heptapeptide 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 2026-04-29 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.
Pharmacological accounts link semax to melanocortin signalling and to modulation of neurotrophic factor expression, particularly brain-derived neurotrophic factor and nerve growth factor. Much of this evidence comes from rodent studies using intranasal delivery, a route chosen because it allows peptides to reach the central nervous system with limited systemic exposure. Whether the same mechanisms operate in humans at comparable magnitude remains an open question. The precise receptor or receptors responsible for the reported behavioural and neuroprotective effects have not been conclusively identified.
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.
| 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 |
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.
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. It was developed as a fragment analog of adrenocorticotropic hormone, modeled specifically on the ACTH(4-10) region. The first four residues reproduce that fragment, while a Pro-Gly-Pro tripeptide is appended at the C-terminus. Work on the compound originated in Russia, where it entered clinical use as an intranasal preparation. Its sequence places it among short regulatory peptides studied for effects on the central nervous system rather than on the adrenal axis.
The C-terminal Pro-Gly-Pro extension is not incidental. Proline-rich tails are known to resist several common peptidases, and the published literature attributes the longer half-life of Semax, relative to unmodified ACTH fragments, to this feature. The modification also removes the melanocyte-stimulating and corticosteroidogenic activity that characterizes longer ACTH-derived sequences. Because the molecule is small and hydrophilic, it is typically formulated as an aqueous solution for intranasal or parenteral delivery. Acetylation or amidation at the termini appears in closely related research peptides and shifts the mass by a fixed increment.
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。
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。
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.
Published research on this peptide originates mainly from Russian laboratories, and the wider international literature is comparatively thin. Studies have used rodent models of stroke, hypoxia, and memory tasks, with a smaller number of human trials reported. Reported outcomes include changes in attention and memory measures, along with effects on neurotrophic factor expression in some experiments. Small sample sizes, inconsistent dosing protocols, and limited independent replication are widely noted limitations, so the strength of the clinical evidence remains an open question.
Ernest O. Lawrence invents the cyclotron. 1934 Josef Mattauch and Richard Herzog develop the double-focusing mass spectrograph. 1936 Arthur J. Dempster develops the spark ionization source. 1937 Aston constructs a mass spectrograph with resolving power of 2000. 1939 Lawrence receives the Nobel Prize in Physics for the cyclotron. 1942 Lawrence develops the Calutron for uranium isotope separation. 1943 Westinghouse markets its mass spectrometer and proclaims it to be "A New Electronic Method for fast, accurate gas analysis". 1946 William Stephens presents the concept of a time-of-flight mass spectrometer. 1953 Wolfgang Paul and Helmut Steinwedel introduce the quadrupole mass filter. 1954 A. J. C. Nicholson (Australia) proposes a hydrogen transfer reaction that will come to be known as the McLafferty rearrangement. 1959 Researchers at Dow Chemical interface a gas chromatograph to a mass spectrometer. 1964 British Mass Spectrometry Society established as first dedicated mass spectrometry society. It holds its first meeting in 1965 in London. 1966 F. H. Field and M. S. B. Munson develop chemical ionization. 1968 Malcolm Dole develops electrospray ionization. 1969 H. D. Beckey develops field desorption. 1974 Comisarow and Marshall develop Fourier Transform Ion Cyclotron Resonance mass spectrometry. 1976 Ronald MacFarlane and co-workers develop plasma desorption mass spectrometry. 1984 John Bennett Fenn and co-workers use electrospray to ionize biomolecules.
C-type natriuretic peptide (CNP) primarily interacts with NPR-B, which triggers an increase in the concentration of cGMP in the cell. This process can lead to several physiological effects, such as tissue remodeling, reduction of pulmonary hypertension and fibrosis, and stimulation of long bone growth. CNP is highly concentrated in vascular endothelial cells and plays a crucial role in regulating vascular tone through its vasodilatory action. Furthermore, CNP has been shown to have anti proliferative effects on vascular smooth muscle and an inhibitory effect on the migration of human coronary artery smooth muscle cells.
Since the start of the Mexican drug war in 2006, drug trafficking organizations have increasingly targeted politicians, especially local leaders in contested areas. Part of the strategy used by criminal groups behind the killings of local figures is the weakening of the local governments. For example, María Santos Gorrostieta Salazar, former mayor of Tiquicheo, Michoacán, who had survived three earlier assassination attempts and the murder of her husband, was abducted and beaten to death in November 2012. Extreme violence puts politicians at the mercy of cartels, allowing them to increase their control of government structures and expand their influence. The 2018 general elections were the deadliest on record, with more than 130 candidates and politicians killed nationwide. Political violence has been most acute in states such as Guerrero, Michoacán, Veracruz, Guanajuato, and Oaxaca, where local governance is highly fragmented. In addition, because mayors usually appoint local police chiefs, they are seen by cartels as key assets in their criminal activities to control the police forces in their areas of influence. Cartels also seek to control the local governments to win government contracts and concessions; these projects help them ingrain themselves in the community and gain the loyalty and respect of the communities in which they operate.
=== Paranthropus dietary reconstruction === Plants can be characterised by the ratio of carbon isotopes they sequester, due to alterations in the evolution of photosynthetic biochemical pathways. So-called C3 plants fix CO2 into a 3-carbon molecule and have a greater proportion of 12C, whereas C4 plants fix it into a 4-carbon molecule, and have a carbon isotope signature with higher 13C. This signature translates across trophic levels and can be used to determine the diets of people and animals. Isotopic analysis has been used to illuminate the diets of the different species of the Paranthropus genus. It was determined that P. boisei had a reduced ratio of C3:C4, meaning they likely consumed a greater proportion of grasses and sedges than trees, shrubs and temperature grasses. P. aethiopicus showed a similar trend, whereas P. robustus was a generalist, with a broader dietary niche. Furthermore, carbon isotope analysis shows that around 2.37 million years ago, hominins displayed a widespread shift to favour C4 plants.
=== Pharmacokinetics === RO5203648 showed favorable pharmacokinetics orally and intravenously in mice, rats, and monkeys. However, it was found to be very rapidly metabolized in human hepatocytes in vitro.
Sources: en.wikipedia.org
Agriculture was once the most important industry in Denmark. Nowadays, it is of minor economic importance. In 2016, 62,000 people, or 2.5% of all employed people worked in agriculture and horticulture. Another 2,000 people worked in fishing. As value added per person is relatively low, the share of national value added is somewhat lower. Total gross value added in agriculture, forestry and fishing amounted to 1.6% of total output in Denmark (in 2017). Despite this, Denmark is still home to various types of agricultural production. Within animal husbandry, it includes dairy and beef cattle, pigs, poultry and fur animals – all sectors that produce mainly for export. Regarding vegetable production, Denmark is a leading producer of grass-, clover- and horticultural seeds. The agriculture and food sector as a whole represented 25% of total Danish commodity exports in 2015. 63% of the land area of Denmark is used for agricultural production – the highest share in the world according to a report from University of Copenhagen in 2017. The Danish agricultural industry is historically characterized by freehold and family ownership, but due to structural development farms have become fewer and larger. In 2020 the number of farms was approximately 33,000, of which approximately 10,000 were owned by full-time farmers.
==== Washing machines ==== There are instances in which silver nanoparticles and colloidal silver are used in consumer goods. Samsung for example claimed that the use of silver nanoparticles in washing machines would help to sterilize clothes and water during the washing and rinsing functions, and allow clothes to be cleaned without the need for hot water. The nanoparticles in these appliances are synthesized using electrolysis. Through electrolysis, silver is extracted from metal plates and then turned into silver nanoparticles by a reduction agent. This method avoids the drying, cleaning, and re-dispersion processes, which are generally required with alternative colloidal synthesis methods. Importantly, the electrolysis strategy also decreases the production cost of Ag nanoparticles, making these washing machines more affordable to manufacture. Samsung has described the system:
Korolev was buoyed by the first successful launches of the R-7 rocket in August and September, which paved the way for the launch of Sputnik 1. Word came that the US was planning to announce a major breakthrough at an International Geophysical Year conference at the National Academy of Sciences in Washington D.C., with a paper titled "Satellite Over the Planet", on October 6, 1957. Korolev anticipated that von Braun might launch a Jupiter-C with a satellite payload on or around October 4 or 5, in conjunction with the paper. He hastened the launch, moving it to October 4. The launch vehicle for PS-1 was a modified R-7 – vehicle 8K71PS number M1-PS – without much of the test equipment and radio gear that was present in the previous launches. It arrived at the Soviet missile base Tyura-Tam in September and was prepared for its mission at launch site number one. The first launch took place on Friday, October 4, 1957, at exactly 10:28:34 pm Moscow time, with the R-7 and the now named Sputnik 1 satellite lifting off the launch pad and placing the artificial "moon" into an orbit a few minutes later. This "fellow traveler", as the name is translated in English, was a small, beeping ball, less than two feet in diameter and weighing less than 200 pounds. But the celebrations were muted at the launch control center until the down-range far east tracking station at Kamchatka received the first distinctive beep ... beep ... beep sounds from Sputnik 1's radio transmitters, indicating that it was on its way to completing its first orbit.
== Mechanisms of action == Levonorgestrel is a progestogen, i.e. a progesterone receptor agonist. The hormonal IUD's primary mechanism of action is to prevent fertilization. The levonorgestrel intrauterine system has several contraceptive effects, although thickening of the cervical mucus appears to be the primary effect. Other effects include making the inside of the uterus become fatal to sperm and thinning of the endometrial lining, but this is not the usual function. Ovulation is not inhibited in all cases. Numerous studies have demonstrated that IUDs primarily prevent fertilization, not implantation. In one experiment involving tubal flushing, fertilized eggs were found in half of women not using contraception, but no fertilized eggs were found in women using IUDs. IUDs also decrease the risk of ectopic pregnancy, which further implies that IUDs prevent fertilization.
Sources: en.wikipedia.org
Sea lilies and feather stars: ligaments connecting ossicles of arms, stalks and cirri. Starfish: body-wall dermis; walls of tube feet. Brittle stars: intervertebral ligaments; autotomy tendons of arm muscles. Sea urchins: ligaments or catch apparatus, connecting spines to tests of sea urchins; tooth ligaments; compass depressor "muscles", which are in fact mostly made of connective tissues. Sea cucumbers: body-wall dermis. Early echinoderms were sessile organisms that fed on suspended particles carried by water currents. Their body was covered with imbricate small skeletal plates. The arrangement of plates suggests that plates worked as sliding joints so as animals to be able to change their body shape: they could possibly take an extended feeding posture and a flat "hiding" posture. The body plates might be connected with catch connective tissue that allowed early echinoderms such postural changes.
==== DEA scheduling ==== In August 2016, the Drug Enforcement Administration (DEA) announced its intention to place the active materials in the kratom plant into Schedule I of the Controlled Substances Act as a warning about an imminent hazard to public safety, citing over 600 calls to poison control centers between 2010 and 2015, and 15 kratom-related deaths between 2014 and 2016. This drew strong protests among those using kratom to deal with chronic pain or wean themselves off opioids or alcohol. A group of 51 members of the U.S. House of Representatives and a group of nine Senators each sent letters to acting DEA administrator Chuck Rosenberg protesting the listing. Around 140,000 people signed an online White House Petition protesting it. The DEA noted the responses but said that it intended to go forward with the listing; a spokesman said: "We can't rely upon public opinion and anecdotal evidence. We have to rely upon science." In October 2016, the DEA withdrew its notice of intent while inviting public comments over a review period ending in December 2016. As of July 2016, Alabama, Arkansas, Indiana, Vermont, and Wisconsin had made kratom illegal, and the US Army had forbidden soldiers from using it. Between February 2014 and July 2016, U.S. law-enforcement authorities "encountered 55 tons of kratom," or roughly "50 million individual doses," according to the International Narcotics Control Board.
== Translocation and peptide loading == The peptide translocation from the cytosol into the lumen of the ER is accomplished by the transporter associated with antigen processing (TAP). TAP is a member of the ABC transporter family and is a heterodimeric multimembrane-spanning polypeptide consisting of TAP1 and TAP2. The two subunits form a peptide binding site and two ATP binding sites that face the cytosol. TAP binds peptides on the cytoplasmic side and translocates them under ATP consumption into the lumen of the ER. The MHC class I molecule is then, in turn, loaded with peptides in the lumen of the ER. The peptide-loading process involves several other molecules that form a large multimeric complex called the peptide-loading complex consisting of TAP, tapasin, calreticulin, calnexin, and Erp57 (PDIA3). Calnexin acts to stabilize the class I MHC α chains prior to β2m binding. Following complete assembly of the MHC molecule, calnexin dissociates. The MHC molecule lacking a bound peptide is inherently unstable and requires the binding of the chaperones calreticulin and Erp57. Additionally, tapasin binds to the MHC molecule and serves to link it to the TAP proteins and facilitates the selection of peptide in an iterative process called peptide editing, thus facilitating enhanced peptide loading and colocalization. Once the peptide is loaded onto the MHC class I molecule, the complex dissociates and it leaves the ER through the secretory pathway to reach the cell surface.
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.
It is described as a synthetic analogue of the ACTH(4–10) fragment, a short segment of adrenocorticotropic hormone. Its sequence differs from that fragment and includes two proline residues, which influence stability and behaviour in solution.