This is a working overview of ACTH(4-10), written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-07-30. Anything still debated is marked as such rather than presented as settled.
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.
Lyophilised powder is normally kept at -20 °C in a desiccated container, with some suppliers recommending -80 °C for long-term archival storage. Repeated freeze-thaw cycles are the most common cause of avoidable loss, so aliquoting before freezing reduces variability between working sessions. Dissolved peptide is far less stable than the dry solid and is usually prepared fresh or held briefly at 4 °C. Aqueous solutions support both hydrolysis of the backbone and oxidation of the N-terminal methionine, and these two routes dominate degradation under ordinary laboratory conditions.
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.
Reported pharmacological work centers on neurotrophic signaling, including changes in BDNF and NGF expression in hippocampal tissue in animal models. Human data come largely from studies conducted in Russia, and how well those results generalize to other populations remains an open question. Regulatory status differs sharply by jurisdiction: Semax is a registered prescription medicine in Russia, while it holds no approved marketing status in the United States or the European Union. Outside such jurisdictions it is generally handled as a research chemical, which affects both documentation and quality expectations.
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.
| 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 |
Verification of a supplied batch generally combines a certificate of analysis with independent testing, because certificates are self-reported documents. A typical package includes a chromatographic trace, a mass spectrum, and a stated water or counter-ion content. Batch-to-batch consistency matters more than a single purity figure when results are compared across experiments. No single mandatory standard governs research-grade peptide release, so laboratories are expected to define their own acceptance criteria. Residual trifluoroacetate from purification is a frequently overlooked counter-ion.
Lyophilized material is chemically stable for extended periods when kept dry, cold, and protected from light. The powder is hygroscopic, so vials should be warmed to room temperature before opening to reduce condensation on the contents. Once dissolved, the peptide is far less stable because peptide bonds are susceptible to hydrolysis and the methionine residue can oxidize. Solutions are typically aliquoted and held at 2-8 °C for short intervals or frozen for longer ones, and repeated freeze-thaw cycles should be avoided.
Routine characterization relies on reversed-phase high-performance liquid chromatography to establish purity and on mass spectrometry to confirm molecular identity. Electrospray ionization and matrix-assisted laser desorption ionization are both used for mass verification. Amino acid analysis and peptide mapping can detect sequence errors. Common impurities include truncated sequences, methionine sulfoxide formed by oxidation, and deamidated products. Chromatograms are usually recorded near 214 nm, where the peptide backbone absorbs, and purity is reported as the percentage area of the principal peak.
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.
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.
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.
Scientific literature on semax is unevenly distributed. A substantial share of published work originates from a small number of laboratories in Russia, while independent replication elsewhere is limited. Human data consist mostly of small trials with short follow-up, and several reported outcomes rely on subjective rating scales. Questions about how much intact peptide reaches the central nervous system after nasal administration, and how long it persists there, are still unresolved. The compound is best described as an active research subject rather than a settled pharmacological agent.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It was derived from the ACTH(4-10) fragment, a short segment of adrenocorticotropic hormone that lacks the hormonal activity associated with the full-length peptide. Researchers at the Institute of Molecular Genetics in Moscow developed the compound during the 1980s. It has been registered as a pharmaceutical product in Russia and several neighbouring countries, where it is supplied as a nasal solution, and it is also sold internationally as a research chemical.
== External links == International Chemical Safety Card 1193 CID 516889 from PubChem ATC codes: A02AC01 (WHO) and A12AA04 (WHO) The British Calcium Carbonate Association – What is calcium carbonate Archived 24 May 2008 at the Wayback Machine CDC – NIOSH Pocket Guide to Chemical Hazards – Calcium Carbonate
=== Acalculous cholecystitis === In acalculous cholecystitis, no stone is in the biliary ducts. It accounts for 5–10% of all cases of cholecystitis and is associated with high morbidity and mortality rates. Acalculous cholecystitis is typically seen in people who are hospitalized and critically ill. Males are more likely to develop acute cholecystitis following surgery in the absence of trauma. It is associated with many causes including vasculitis, chemotherapy, major trauma or burns. The presentation of acalculous cholecystitis is similar to calculous cholecystitis. Patients are more likely to have yellowing of the skin (jaundice) than in calculous cholecystitis. Ultrasonography or computed tomography often shows an immobile, enlarged gallbladder. Treatment involves immediate antibiotics and cholecystectomy within 24–72 hours.
Reaction (1) is only possible if energetically allowed, i.e. if the proton affinity of R is higher than the proton affinity of H2O (691 kJ/mol). As most components of ambient air possess a lower proton affinity than H2O (e.g. N2, O2, Ar, CO2, etc.) the H3O+ ions only react with VOC trace components and the air itself acts as a buffer gas. Moreover, due to the low concentrations of trace components one can assume that the total number of H3O+ ions remains nearly unchanged, which leads to the equation
Side effects of levodopa include nausea, the wearing-off phenomenon, dopamine dysregulation syndrome, and levodopa-induced dyskinesia, among others. The drug is a centrally permeable monoamine precursor and prodrug of dopamine and hence acts as a dopamine receptor agonist. Chemically, levodopa is an amino acid, a phenethylamine, and a catecholamine. The major reason for enhanced risks for levodopa induced dyskinesia (LID) and OFF phases during late PD is the progressive dying of nigrostriatal dopaminergic neurons. This results in the conversion of levodopa into dopamine in serotonergic neurons (which cannot re-uptake dopamine and have no proper regulatory capacity for dopamine synthesis) becoming the major dopamine source in the dorsal striatum, leading to the striatal dopamine concentration following the pulsatile oral administration of levodopa with large fluctuations (see the schematic graph figure). On the other hand, in a disease like Segawa syndrome, in which dopamine synthesis is low but without progressive degeneration of dopaminergic neurons, lifelong administration of low doses of levodopa is believed to be without serious side effects. Levodopa was first synthesized and isolated in the early 1910s. The antiparkinsonian effects of levodopa were discovered in the 1950s and 1960s. Following this, it was introduced for the treatment of Parkinson's disease in 1970.
=== Hormone signals === The hormones insulin and cholecystokinin (CCK) are released from the GI tract during food absorption and act to suppress the feeling of hunger. CCK is key in suppressing hunger because of its role in inhibiting neuropeptide Y. Glucagon and epinephrine levels rise during fasting and stimulate hunger. Ghrelin, a hormone produced by the stomach, is an appetite stimulant.
Sources: en.wikipedia.org
AMM designs have diversified significantly since the early days of the field. A major route is the introduction of bistability to produce molecular switches, featuring two distinct configurations for the molecule to convert between. This has been perceived as a step forward from the original molecular shuttle which consisted of two identical sites for the ring to move between without any preference, in a manner analogous to the ring flip in an unsubstituted cyclohexane. If these two sites are different from each other in terms of features like electron density, this can give rise to weak or strong recognition sites as in biological systems — such AMMs have found applications in catalysis and drug delivery. This switching behavior has been further optimized to acquire useful work that gets lost when a typical switch returns to its original state. Inspired by the use of kinetic control to produce work in natural processes, molecular motors are designed to have a continuous energy influx to keep them away from equilibrium to deliver work. Various energy sources are employed to drive molecular machines today, but this was not the case during the early years of AMM development. Though the movements in AMMs were regulated relative to the random thermal motion generally seen in molecules, they could not be controlled or manipulated as desired. This led to the addition of stimuli-responsive moieties in AMM design, so that externally applied non-thermal sources of energy could drive molecular motion and hence allow control over the properties.
Prakash and Kamal Hinduja, as well as their son Ajay and his wife Namrata, who are members of Britain's richest family, are convicted and sent to prison for exploiting staff brought from India to work in their Geneva villa. 22 June Thousands of people join the "Restore Nature Now" march through central London to Parliament Square, demanding action on the UK's declining wildlife. The UK Health Security Agency (UKHSA) and Met Office issue a yellow heat health alert for most of England, to come into force from the morning of Monday 24 June and remain in place until the afternoon of Thursday 27 June. Following criticism from other party leaders over his comments about Putin, Nigel Farage pens an op-ed in The Telegraph in which he says he has never been an "apologist or supporter" of Putin, but that "if you poke the Russian bear with a stick, don't be surprised if he responds". 23 June Flights from Manchester Airport's Terminals 1 and 2 are cancelled following a "major" power cut. 2024 United Kingdom general election date betting controversy: The Sunday Times reports that Nick Mason, the Conservative Party's chief data officer, has become the fourth person to face investigation by the Gambling Commission for betting on the date of the election. BBC News reports that the Gambling Commission's investigation involves more people than those already named. 24 June Princess Anne is taken to hospital with a head injury thought to have been caused by a horse. The UK records its hottest temperature of 2024 so far, with 28.3 °C recorded at Wisley in Surrey.
=== Lungs === Individuals with Marfan syndrome may be affected by various lung-related problems. Spontaneous pneumothorax can be present, but is not common. In spontaneous unilateral pneumothorax, air escapes from a lung and occupies the pleural space between the chest wall and a lung. The lung becomes partially compressed or collapsed. This can cause pain, shortness of breath, cyanosis, and if not treated, death. Other possible pulmonary manifestations of MFS include sleep apnea, which is typically treated with BiPAP. and idiopathic obstructive lung disease. Pathologic changes in the lungs have been described such as cystic changes, emphysema, pneumonia, bronchiectasis, bullae, apical fibrosis and congenital malformations such as middle lobe hypoplasia.
Genetic defects in the creatine biosynthetic pathway enzymes lead to various severe neurological defects. Defects in the two synthesis enzymes cause L-arginine:glycine amidinotransferase deficiency and guanidinoacetate methyltransferase deficiency. Both biosynthetic defects are inherited in an autosomal recessive manner. Creatine transporter defect, characterized by insufficient transport of creatine to the brain, is caused by mutations in SLC6A8 and is inherited in an X-linked manner.
The scheme might be made far more attractive to the majority of Jews if it held out to them the prospect that when in course of time the Jewish colonists in Palestine grow strong enough to cope with the Arab population they may be allowed to take the management of the internal affairs of Palestine (with the exception of Jerusalem and the holy places) into their own hands. Sykes, having seen the telegram, had discussions with Picot and proposed (making reference to Samuel's memorandum) the creation of an Arab Sultanate under French and British protection, some means of administering the holy places along with the establishment of a company to purchase land for Jewish colonists, who would then become citizens with equal rights to Arabs. Shortly after returning from Petrograd, Sykes briefed Samuel, who then briefed a meeting of Gaster, Weizmann and Sokolow. Gaster recorded in his diary on 16 April 1916: "We are offered French-English condominium in Palest[ine]. Arab Prince to conciliate Arab sentiment and as part of the Constitution a Charter to Zionists for which England would stand guarantee and which would stand by us in every case of friction ... It practically comes to a complete realisation of our Zionist programme.
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.
The sequence is Met-Glu-His-Phe-Pro-Gly-Pro, a seven-residue peptide. The first four residues correspond to the ACTH(4-10) fragment, and Pro-Gly-Pro is added at the C-terminus. N-acetylated versions also appear in the literature and differ in mass.