If you have been reading about semax 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 2026-04-23. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
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.
Pharmacokinetic accounts emphasize rapid breakdown. After intravenous dosing the intact peptide disappears from blood within minutes, and nasal delivery produces low but measurable concentrations. Metabolites rather than the parent molecule may account for part of the observed activity, although the relative contribution is unresolved. Dosing in the literature varies widely and no optimal schedule has been agreed. These gaps are regularly cited as a reason the findings have not produced broad clinical adoption beyond the original research setting.
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.
| 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。
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.
Solid semax is typically supplied as a lyophilised powder that is hygroscopic and sensitive to moisture, light, and repeated temperature cycling. Long-term storage of the dry peptide is generally recommended at approximately -20 degrees Celsius, while shorter working periods may use refrigeration at 2 to 8 degrees Celsius. Vials should remain tightly closed and desiccated when brought to room temperature, because condensation can damage the material before it is weighed. Dividing a batch into aliquots is preferable to thawing one container repeatedly.
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.
Executive mental function was measured with standard tests, including the ability to say the sequence 1-A, 2-B, 3-C..., to name a number of animals in one minute, and with the Stroop test. The study found that those individuals with lower skeletal muscle mass at the start of the study declined in their executive mental function considerably more sharply than those with higher muscle mass. Memory, as well as psychomotor speed, on the other hand, did not correlate with skeletal muscle mass. Thus, larger muscle mass, with a concomitantly larger secretome, appeared to have the endocrine function of protecting the executive mental function of individuals over the age of 65.
According to the study, however, when estimating the length of their partner's penis, most women would say a size significantly smaller than what their partner was recorded to be. This suggests that perception of size is not entirely accurate. The visual impression of the size is not necessarily in correlation with the feeling in the vulva and vagina. A very long penis can cause dyspareunia, if the man does not understand how to use it carefully.
With opposition from employers and individuals to such a large peacetime liability, the target of 15,000 volunteers proved over-ambitious and the force peaked at 4,262 in October 1963, then dropping to around 2,400 by 1968. Nevertheless, the first batch of these so-called 'Ever Readies' was sent to Libya in 1963, followed by 200 to the Far East later that year. In 1965, 175 were called out, the majority deploying to Aden, where one of their officers, Lieutenant Mike Smith, won an MC.
Selenocysteine (symbol Sec or U, in older publications also as Se-Cys) is the 21st proteinogenic amino acid. Selenoproteins contain selenocysteine residues. Selenocysteine is an analogue of the more common cysteine with selenium in place of the sulfur. Selenocysteine is present in several enzymes (for example glutathione peroxidases, tetraiodothyronine 5′ deiodinases, thioredoxin reductases, formate dehydrogenases, glycine reductases, selenophosphate synthetase 2, methionine-R-sulfoxide reductase B1 (SEPX1), and some hydrogenases). It occurs in all three domains of life, including important enzymes (listed above) present in humans. Selenocysteine was discovered in 1974 by biochemist Thressa Stadtman at the National Institutes of Health.
Sources: en.wikipedia.org
== External links == The Nuclear Science web portal Nucleonica The Karlsruhe Nuclide Chart National Nuclear Data Center Portal to large repository of free data and analysis programs from NNDC National Isotope Development Center Coordination and management of the production, availability, and distribution of isotopes, and reference information for the isotope community Isotope Development & Production for Research and Applications (IDPRA) U.S. Department of Energy program for isotope production and production research and development International Atomic Energy Agency Homepage of International Atomic Energy Agency (IAEA), an Agency of the United Nations (UN) Atomic Weights and Isotopic Compositions for All Elements Static table, from NIST (National Institute of Standards and Technology) Atomgewichte, Zerfallsenergien und Halbwertszeiten aller Isotope Exploring the Table of the Isotopes at the LBNL Current isotope research and information isotope.info Emergency Preparedness and Response: Radioactive Isotopes by the CDC (Centers for Disease Control and Prevention) Chart of Nuclides Archived 2018-10-10 at the Wayback Machine Interactive Chart of Nuclides (National Nuclear Data Center) Interactive Chart of the nuclides, isotopes and Periodic Table Archived 2008-09-30 at the Wayback Machine The LIVEChart of Nuclides – IAEA with isotope data. Annotated bibliography for isotopes from the Alsos Digital Library for Nuclear Issues The Valley of Stability (video) – a virtual "flight" through 3D representation of the nuclide chart, by CEA (France)
=== Use of meloxicam in cats === The issue of using meloxicam in cats involves conflicting guidelines, differing legislation, and a narrow therapeutic safety margin that can easily turn the drug from cure to poison. More specifically:
BMA Scotland calls off a planned strike by junior doctors in Scotland while it consults its members on a revised 12.4% pay offer for 2023–24. 8 July – The Union Chain Bridge, which spans the River Tweed, linking England and Scotland, is named as an International Historic Civil Engineering Landmark. 10 July – Bus operator First Glasgow announces it is withdrawing all of its night-time services from Glasgow, doing so from 31 July. 11 July – Following his trial and conviction at Glasgow High Court, Logan Doig is sentenced to a twelve and a half year extended sentence for the rape and sexual assault of four women, and the sexual assault of a fifth. He must serve at least nine and a half years in custody and is placed on the Sex Offenders Register indefinitely. Doig's victims subsequently meet with Dorothy Bain, the Lord Advocate, to argue for a change in the way victims of sex crimes are treated in court. 12 July – Glasgow's Burrell Collection is named the 2023 Art Fund Museum of the Year. 13 July Patients are evacuated from two wards at Paisley's Royal Alexandra Hospital after Legionella bacteria is found in the water supply. Emails regarding the arrest of Peter Murrell are released and show that the Scottish Government was informed of the arrest shortly after it occurred. 14 July – Lord Advocate Dorothy Bain KC orders a review of how diversion from prosecution (referring an offender to social services rather than prosecuting them) is used in sex crime cases.
A memorial collection of scientific papers contributed by former pupils and colleagues of Robertson, edited by Sir Charles James Martin and Hedley R. Marston, was published in January 1932 as a special issue of The Australian Journal of Experimental Biology and Medical Science. A memorial window, commissioned by his wife — designed and produced by Edith Lungley, a member of the British Society of Master Glass Painters — was presented to the University of Adelaide, and was unveiled in the Mitchell Building at a ceremony on 18 March 1932 by Sir George Murray, the university's Chancellor. The Medical Sciences Club of South Australia sponsored the annual Brailsford Robertson Memorial Lecture in Robertson's memory. Notable lecturers have been: Sir Howard Florey (1944), Edward Slater (1957)[9], Frank G. Young (1960)[10], Derek Denny-Brown (1964)[11], M.F.A. Woodruff (1965)[12], Stephen Boyden (1968)[13], Geoffrey Burnstock (1971), Frank Macfarlane Burnet (1976)[14], and John B. West (1978). In 2001, the Brailsford Robertson Award was jointly created by the Commonwealth Scientific and Industrial Research Organisation (CSIRO) and the University of Adelaide specifically to encourage collaborative research in areas of health identified as strategic priorities by the CSIRO Food and Nutritional Sciences division and the University of Adelaide. In 2001, the former CSIRO Division of Animal Nutrition Building on the University of Adelaide's campus was re-named the Brailsford Robertson Building.
Gram Parsons died from a drug and alcohol overdose on September 19, 1973. He was 26 years old. In the late 1960s, Parsons began to vacation at Joshua Tree National Monument in southeastern California, where he used psychedelics and said he experienced UFO sightings. After splitting from Burrell, Parsons often spent his weekends there with Margaret Fisher and Phil Kaufman. Scheduled to resume touring in October 1973, Parsons decided to go on another recuperative excursion on September 17. Accompanying him were Fisher, his assistant Michael Martin, and Martin's girlfriend Dale McElroy. On both nights of their stay, Parsons retreated to the desert, consuming large amounts of alcohol and barbiturates, while the rest of the group visited bars in nearby Yucca Valley. On September 18, Martin drove back to Los Angeles to resupply the group with marijuana. That night, Parsons challenged Fisher and McElroy to drink with him; Fisher did not drink and McElroy was recovering from illness. Parsons said that he would drink for the three of them and drank six double tequilas. The three then went to the Joshua Tree Inn, where Parsons purchased morphine from an unknown woman; after being injected by her in Room No. 1, he overdosed. Fisher gave Parsons an ice cube suppository, and then a cold shower and moved him to Room No. 8. She put him to bed and went out to buy coffee in the hope of reviving him, leaving McElroy to stand guard. As his breathing became irregular and then ceased, McElroy attempted resuscitation. After all attempts failed, they called an ambulance.
Sources: en.wikipedia.org
== Prevention == As for the prevention of childhood malnutrition, there needs to be public health changes such as improving agriculture and improving access to healthcare to effectively reduce the rates of malnutrition in children. By educating individuals of childbearing age on proper nutrition and health during and after pregnancy, they can provide their children with the appropriate nutrients from a young age. By ensuring they are equipped with the proper education and resources, caretakers and infants are in better health, ultimately preventing childhood malnutrition. Because edema can hide decreased muscle mass, it can be hard to diagnose kwashiorkor in young children; however, if cases are overlooked, children become more susceptible to infections and can ultimately lead to morbidity and mortality. To prevent this from happening, parents can be educated on proper nutrition and the importance of breastfeeding infants to ensure they receive all the nutrients they need. A diet rich in carbohydrates, fats that provide at least 10% of the total caloric needs, and proteins that provide 15% of the caloric needs can prevent kwashiorkor. Proteins can be found in the following foods
==== Side reactions ==== When methionine is followed by serine or threonine, side reactions can occur that destroy the methionine without peptide bond cleavage. Normally, once the iminolactone is formed (refer to figure), water and acid can react with the imine to cleave the peptide bond, forming a homoserine lactone and new C-terminal peptide. However, if the adjacent amino acid to methionine has a hydroxyl or sulfhydryl group, this group can react with the imine to form a homoserine without peptide bond cleavage. These two cases are shown in the figure.
Sanders voted against the resolutions authorizing the use of force against Iraq in 1991 and 2002, and he opposed the 2003 invasion of Iraq. He voted for the 2001 Authorization for Use of Military Force Against Terrorists that has been cited as the legal justification for controversial military actions since the September 11 attacks. He especially opposed the Bush administration's decision to start a war unilaterally.
== Properties == Polymer-Protein nanoparticles not only contain the traditional properties of nanoparticles, but also have their own unique properties based on the properties of specific proteins. Because they are proteinaceous, they have high biocompatibility, biodegradability and biofunctionality. Protein-polymer bioconjugates which is the building block of Polymer-Protein hybrids exhibit a unique array of properties such as: light-switching effects, acoustic signal capture, thermal energy transfer, and magnetic signal response.
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.
The main proposal is modulation of neurotrophic factors such as brain-derived neurotrophic factor, supported largely by animal experiments. Receptor-level targets have not been firmly established. Most reviews describe the mechanism as only partially characterized.