If you have been reading about ACTH fragment 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 2026-03-24. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Purity assay | RP-HPLC, UV 214 nm | Typical research grade 95 percent or higher |
| Mass confirmation | ESI-MS or MALDI-TOF | Compared with theoretical value |
| Main degradation route | Methionine oxidation | Sulfoxide formation in solution |
| Powder storage | -20 °C, desiccated | Amber vial, minimal headspace |
| Working solution | Sterile water or saline | Prepare fresh; avoid repeated thawing |
Material sold for laboratory use varies widely in stated purity and documentation. A certificate of analysis should list the analytical method, the column and detector used, and the observed purity value. Independent verification by an outside laboratory is the practical way to confirm identity when documentation is absent or internally inconsistent. Regulatory status differs by country, and a product legal in one jurisdiction may be unapproved or controlled in another.
Identity and purity of semax are established with reversed-phase high-performance liquid chromatography coupled to ultraviolet detection, usually at 214 nanometres. Mass spectrometry, most often electrospray ionisation in positive mode, confirms the molecular mass and reveals truncated sequences. Amino acid analysis and peptide mapping after enzymatic digestion provide additional structural confirmation. Laboratories typically report purity as the percentage area of the main peak, a figure that does not capture isomeric or oxidised variants unless the method resolves them.
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.
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.
Semax binds to melanocortin receptors and is thought to influence neuronal survival and plasticity rather than to act through the adrenal axis. Laboratory work has shown increased expression of brain-derived neurotrophic factor and nerve growth factor in treated tissue. Changes in c-Fos, a marker of neuronal activation, have also been reported. Because the peptide is rapidly degraded by peptidases, its effects are generally attributed to downstream signaling cascades rather than to sustained receptor occupancy.
=== RTG (radioisotope thermoelectric generator) power generation === As 241Am has a roughly similar half-life to 238Pu (432.6 years Am-241, 87.7 years Pu-238, decay energies nearly the same), it has been proposed as an active isotope of radioisotope thermoelectric generators, for use in spacecraft. Even though americium-241 produces less heat and electricity than plutonium-238 (the power yield is 114.7 milliwatts per gram [3.25 watts per ounce] for 241Am vs. 570 mW/g [16 W/oz] for 238Pu) and its radiation poses a greater threat to humans owing to gamma emission, it has advantages for long duration missions with its significantly longer half-life. The European Space Agency is working on RTGs based on americium-241 for its space probes as a result of the global shortage of plutonium-238 and easy access to americium-241 in Europe from nuclear waste reprocessing. Its shielding requirements in an RTG are the second lowest of all possible isotopes: only 238Pu requires less. An advantage over 238Pu is that it is produced as nuclear waste already. Prototype designs of 241Am RTGs expect 2–2.2 We/kg for a 5–50 We design, putting 241Am RTGs at parity with 238Pu RTGs within that power range, as the vast majority of the mass of an RTG is not the radioisotope, but the thermoelectrics, radiators, and isotope containment mass.
== Adverse effects == To lessen the risk of developing ketoacidosis (a serious condition in which the body produces high levels of blood acids called ketones) after surgery, the FDA has approved changes to the prescribing information for SGLT2 inhibitor diabetes medicines to recommend they be stopped temporarily before scheduled surgery. Canagliflozin, dapagliflozin, and empagliflozin should each be stopped at least three days before, and ertugliflozin should be stopped at least four days before scheduled surgery. Symptoms of ketoacidosis include nausea, vomiting, abdominal pain, tiredness, and trouble breathing. A potential interaction between dapagliflozin and lithium concomitant causing a reduction in serum lithium levels was bulletined in 2022.
By oral route, phenethylamine's half-life is 5–10 minutes; endogenously produced PEA in catecholamine neurons has a half-life of roughly 30 seconds. In humans, PEA is metabolized by phenylethanolamine N-methyltransferase (PNMT), monoamine oxidase A (MAO-A), monoamine oxidase B (MAO-B), the semicarbazide-sensitive amine oxidases (SSAOs) AOC2 and AOC3, flavin-containing monooxygenase 3 (FMO3), and aralkylamine N-acetyltransferase (AANAT). N-Methylphenethylamine, an isomer of amphetamine, is produced in humans via the metabolism of phenethylamine by PNMT. β-Phenylacetic acid is the primary urinary metabolite of phenethylamine and is produced via monoamine oxidase metabolism and subsequent aldehyde dehydrogenase metabolism. Phenylacetaldehyde is the intermediate product which is produced by monoamine oxidase and then further metabolized into β-phenylacetic acid by aldehyde dehydrogenase. When the initial phenylethylamine concentration in the brain is low, brain levels can be increased 1000-fold when taking a monoamine oxidase inhibitor (MAOI), particularly a MAO-B inhibitor, and by 3–4 times when the initial concentration is high.
Kimon Georgiev became prime minister on 19 May 1934, after the coup d'état. He served as Minister of Foreign Affairs and Religious Affairs (19-23 May 1934) and Minister of Justice (23 May 1934 – 22 January 1935) and temporarily served as Minister of War on 19 May 1934. Kimon Georgiev led the new Cabinet, which was primarily made up of Zveno and Military League representatives. Although they denounced the coup, the other bourgeois parties and the non-fascist bourgeois parties accepted it. The BCP called it a fascist coup, but they were unable to put up a united front to fight it due to mistakes in secretarian doctrine. The coup's perpetrators said in their manifesto that a "national supra-party power" would be established. They abolished the Parliament, dissolved the IMRO, and restructured the governmental apparatus on a fascist basis.
The HaloTag is a hydrolase, which has a genetically modified active site, which specifically binds the reactive chloroalkane linker and has an increased rate of ligand binding. The reaction that forms the bond between the protein tag and chloroalkane linker is fast and essentially irreversible under physiological conditions due to the terminal chlorine of the linker portion. In the aforementioned reaction, nucleophilic attack of the chloroalkane reactive linker causes displacement of the halogen with an amino acid residue, which results in the formation of a covalent alkyl-enzyme intermediate. This intermediate would then be hydrolyzed by an amino acid residue within the wild-type hydrolase. This would lead to regeneration of the enzyme following the reaction. However, in the modified haloalkane dehalogenase (HaloTag), the reaction intermediate cannot proceed through a subsequent reaction because it cannot be hydrolyzed due to the mutation in the enzyme. This causes the intermediate to persist as a stable covalent adduct with which there is no associated back reaction.
Sources: en.wikipedia.org
=== Water treatment === Scale deposition in boilers can reduce heat transfer efficiency and increase energy consumption. Antiscalants are added to boiler feedwater to prevent scale formation on heat transfer surfaces, piping, and other boiler components. Water treatment plants can use antiscalants to maintain filtration.
== Disease and Pharmaceutical Relevance == While one study which utilized mice models indicated that acrosin is not a necessary component of zona pellucida penetration, other studies in humans have shown an association between low acrosomal proteinase activity and infertility. Other research groups have demonstrated a significant correlation between acrosin activity and sperm motility. In rabbit models, an intravaginal contraceptive device that secreted tetradecyl sodium sulfate, a known inhibitor of acrosin and hyaluronidases, had a complete contraceptive effect. Although its exact mechanism of action is not entirely clear, acrosin could thus serve as a novel target for contraceptive agents. Acrosin may represent as a uniquely druggable target due to its location and high cellular specificity. Thus, developing inhibitors of acrosin could provide the basis for safe, reversible male contraceptives, or female contraceptives through the use of intravaginal contraceptive devices. Moreover, as serine proteases are important in the potentiation of HIV, research has found that an acrosin inhibitor, 4'-acetamidophenyl 4-guanidinobenzoate, possess the ability to inhibit HIV infection in virus-inoculated lymphocytes. This suggests the further role of acrosin inhibitors as potentially viable agents in the prevention of HIV transmission.
Thallium and lead atoms are about the same size as indium and tin atoms respectively, but from bismuth to radon the 6p atoms are larger than the analogous 5p atoms. This happens because when atomic nuclei become highly charged, special relativity becomes needed to gauge the effect of the nucleus on the electron cloud. These relativistic effects result in heavy elements increasingly having differing properties compared to their lighter homologues in the periodic table. Spin–orbit interaction splits the p subshell: one p orbital is relativistically stabilized and shrunken (it fills in thallium and lead), but the other two (filling in bismuth through radon) are relativistically destabilized and expanded. Relativistic effects also explain why gold is golden and mercury is a liquid at room temperature. They are expected to become very strong in the late seventh period, potentially leading to a collapse of periodicity. Electron configurations are only clearly known until element 108 (hassium), and experimental chemistry beyond 108 has only been done for elements 112 (copernicium) through 115 (moscovium), so the chemical characterization of the heaviest elements remains a topic of current research. The trend that atomic radii decrease from left to right is also present in ionic radii, though it is more difficult to examine because the most common ions of consecutive elements normally differ in charge.
The stigma placed on mental health makes many men believe showing signs of vulnerability could be considered weak. Men experience immense amounts of internalized stigma from societal expectations, causing symptoms such as isolation, depression, anxiety, and resistance to treatment.
The Food and Drug Administration (FDA) is a federal agency of the United States Department of Health and Human Services (HHS). The FDA is responsible for protecting and promoting public health through the control and supervision of food safety, tobacco products, caffeine products, dietary supplements, prescription and over-the-counter pharmaceutical drugs (medications), vaccines, biopharmaceuticals, blood transfusions, medical devices, electromagnetic radiation emitting devices (ERED), cosmetics, animal foods & feed, and veterinary products. The FDA's primary focus is enforcing the Federal Food, Drug, and Cosmetic Act (FD&C). However, the agency also enforces other laws, notably Section 361 of the Public Health Service Act as well as associated regulations. Much of this regulatory-enforcement work is not directly related to food or drugs but involves other regulated products like lasers, cellular phones, and condoms. In addition, the FDA uses its authority to mitigate diseases in a variety of contexts, from household pets to human sperm for use in assisted reproduction. The FDA is led by the commissioner of food and drugs, who is appointed by the president with the advice and consent of the Senate. The commissioner reports to the secretary of health and human services. Marty Makary is the current commissioner. The FDA's headquarters is located in the White Oak area of Silver Spring, Maryland, occupying the former Naval Ordnance Laboratory. The agency has 223 field offices and 13 laboratories located across the 50 states, the United States Virgin Islands, and Puerto Rico.
Sources: en.wikipedia.org
This prevents BioBricks from being used to create fusion proteins, as the 6bp scar sequence codes for a tyrosine and a stop codon, causing translation to be terminated after the first domain is expressed, while the 8bp scar sequence causes a frameshift, preventing continuous readthrough of the codons. To offer alternative scar sequences that for example give a 6bp scar, or scar sequences that do not contain stop codons, other assembly standards such as the BB-2 Assembly, BglBricks Assembly, Silver Assembly and the Freiburg Assembly were designed. While the easiest method to assemble BioBrick parts is described above, there also exist several other commonly used assembly methods that offer several advantages over the standard assembly. The 3 antibiotic (3A) assembly allows for the correct assembly to be selected via antibiotic selection, while the amplified insert assembly seeks to overcome the low transformation efficiency seen in 3A assembly. The BioBrick assembly standard has also served as inspiration for using other types of endonucleases for DNA assembly. For example, both the iBrick standard and the HomeRun vector assembly standards employ homing endonucleases instead of type II restriction enzymes.
Pregabalin was approved for medical use in the United States in 2004. In the US, pregabalin is a Schedule V controlled substance under the Controlled Substances Act of 1970, which means it has low abuse potential compared to substances in Schedules I–IV, though there is still a potential for misuse. It is available as a generic medication. In 2023, it was the 78th most commonly prescribed medication in the United States, with more than 8 million prescriptions.
=== Pregnancy === Opioids such as hydrocodone cross the placenta, and can therefore affect the fetus. Studies have shown a possible association between opioids and adverse outcomes such as birth defects, poor fetal growth, stillbirth, and preterm delivery. Prolonged use of opioids by a pregnant mother can also lead to neonatal withdrawal syndrome. NSAIDs such as ibuprofen should generally be avoided in pregnancy, as there are conflicting reports of birth defects after in utero exposure. However, it is accepted that NSAIDs prevent closure of the fetal ductus arteriosus, which happens during the later stages of pregnancy. Because of this, ibuprofen should be avoided after 30 weeks gestation.
== Myths == Some popular beliefs attached to weight loss have been shown to either have less effect on weight loss than commonly believed or are actively unhealthy. According to Harvard Health, the idea of metabolic rate being the "key to weight" is "part truth and part myth" as while metabolism does affect weight loss, external forces such as diet and exercise have an equal effect. They also commented that the idea of changing one's rate of metabolism is under debate. Diet plans in fitness magazines are also often believed to be effective but may actually be harmful by limiting the daily intake of important calories and nutrients which can be detrimental depending on the person and are even capable of driving individuals away from weight loss.
Soils contaminated by heavy metals can be remediated by one or more of the following technologies: isolation; immobilization; toxicity reduction; physical separation; or extraction. Isolation involves the use of caps, membranes or below-ground barriers in an attempt to quarantine the contaminated soil. Immobilization aims to alter the properties of the soil so as to hinder the mobility of the heavy contaminants. Toxicity reduction attempts to oxidise or reduce the toxic heavy metal ions, via chemical or biological means into less toxic or mobile forms. Physical separation involves the removal of the contaminated soil and the separation of the metal contaminants by mechanical means. Extraction is an on or off-site process that uses chemicals, high-temperature volatization, or electrolysis to extract contaminants from soils. The process or processes used will vary according to contaminant and the characteristics of the site.
Sources: en.wikipedia.org
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.
The main chemical risks are methionine oxidation and backbone hydrolysis in solution. Moisture and repeated temperature cycling accelerate both processes. Dry powder held cold and desiccated is considerably more stable than any reconstituted preparation.
It holds a medicine registration in Russia, where it has been used clinically for decades. In most other countries it is treated as a research chemical. That split explains the uneven distribution of clinical literature.
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.