ACTH(4–10) comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Updated 2025-10-02. 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.
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.
The proposed mechanism centres on neurotrophic signalling rather than direct receptor activation. Semax is reported to increase expression of brain-derived neurotrophic factor and nerve growth factor in several brain regions, and to shift the balance between excitatory and inhibitory neurotransmitter systems. Interaction with melanocortin receptors has been suggested because of the parent ACTH fragment. Many of these findings come from rodent studies, and the extent to which they translate to human physiology remains an open question.
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.
| 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 |
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.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It is described in the literature as an analogue of the ACTH(4–10) fragment, a short N-terminal portion of adrenocorticotropic hormone that retains some neurotropic activity without the full hormonal effects of the parent peptide. The molecule carries a methionine residue at the N-terminus and two proline residues near the C-terminus, features that shape both its interactions with receptor systems and its chemical stability. The free peptide corresponds to the formula C37H51N9O10S and a molecular mass near 813.9 Da.
== Mechanism == The hallmark feature of ferroptosis is the iron-dependent accumulation of oxidatively damaged phospholipids, i.e., lipid peroxides. The implication of Fenton chemistry via iron is crucial for the generation of reactive oxygen species and this feature can be exploited by sequestering iron in lysosomes. Reactive oxygen species (ROS) driving ferroptosis originate from three primary sources: the iron-dependent Fenton reaction, mitochondrial oxidative phosphorylation, and the NADPH oxidase (NOX) enzyme family. The NOX family, including NOX1, NOX2 (CYBB), and NOX4, transports electrons across the plasma membrane to produce superoxide and downstream ROS. The pentose phosphate pathway supplies NADPH, which serves as the essential electron donor for GPX4, FSP1/AIFM2, NOX, and POR — meaning that a higher intracellular NADPH ratio correlates with increased resistance to ferroptosis. The incorporation of polyunsaturated fatty acids (PUFAs) into membrane phospholipids is a prerequisite for ferroptosis. Two key enzymes govern this process: acyl-CoA synthetase long-chain family member 4 (ACSL4) activates PUFAs such as arachidonic acid and adrenic acid, and lysophosphatidylcholine acyltransferase 3 (LPCAT3) incorporates these activated PUFAs into the phospholipid bilayer. Monounsaturated fatty acids (MUFAs), including oleic acid and palmitoleic acid, compete with PUFAs for membrane incorporation and suppress ferroptosis due to their lower susceptibility to peroxidation.
A norepinephrine and dopamine disinhibitor (NDDI or NDD) is a drug that acts at specific sites to disinhibit downstream norepinephrine and dopamine release in the brain. Agomelatine, an antidepressant which disinhibits norepinephrine and dopamine release in the frontal cortex by antagonizing 5-HT2C receptors, was the first drug to be described as an NDDI. While many other drugs also antagonize 5-HT2C receptors to some degree or another, they tend to be very non-specific in their actions, and as a result, the term "NDDI" has generally, though not always (for instance, fluoxetine has been called an NDDI in addition to SSRI due to its (weak) blockade of 5-HT2C), been reserved for describing newer, more selective agents in which disinhibition of norepinephrine and dopamine release is their primary mechanism of action. Another drug that has been referred to as an NDDI in the medical literature is flibanserin, which is approved as a treatment for hypoactive sexual desire disorder in premenopausal women. Flibanserin disinhibits norepinephrine and dopamine release in the prefrontal cortex by activating postsynaptic 5-HT1A receptors in this area. Aside from agomelatine, fluoxetine, flibanserin, mianserin and mirtazapine, as of present, no other drugs have been described as NDDIs in the medical literature, despite the fact that many other existing drugs possess effects consistent with those of the definition of an NDDI. In any case, more drugs labeled specifically as NDDIs may be seen in the future.
=== Receiver details === In addition to triggering the broadcast signal, the output of the transmitter trigger signal was also sent to the receiver hut. Here it fed the input to a time base generator that drove the X-axis deflection plates of the CRT display. This caused the electron beam in the tube to start moving left-to-right at the instant that the transmission was completed. Due to the slow decay of the pulse, some of the transmitted signal was received on the display. This signal was so powerful it overwhelmed any reflected signal from targets, which meant that objects closer than about 5 miles (8.0 km) could not be seen on the display. To reduce this period even to this point required the receiver to be hand-tuned, selecting the decoupling capacitors and impedance of the power supplies. The receiver system, built by A.C. Cossor to a TRE design, was a multiple-stage superheterodyne. The signal from the selected antennas on the receiver towers was fed through the radiogoniometer and then into a three-stage amplifier, with each stage housed in a metal screen box to avoid interference between the stages. Each stage used a Class B amplifier arrangement of EF8s, special low noise, "aligned-grid" pentodes. The output of the initial amplifier was then sent to the intermediate frequency mixer, which extracted a user-selectable amount of the signal, 500, 200 or 50 kHz as selected by a switch on the console. The first setting allowed most of the signal through, and was used under most circumstances.
Culture in German states has been shaped by major intellectual and popular currents in Europe, both religious and secular, and German scientists, writers and philosophers have played a significant role in the development of Western thought. Global opinion polls from the BBC revealed that Germany is recognised for having the most positive influence in the world in 2013 and 2014. Germany is well known for such folk festivals as the Oktoberfest and Christmas customs, which include Advent wreaths, Christmas pageants, Christmas trees, Stollen cakes, and other practices. As of 2025, UNESCO inscribed 55 properties in Germany on the World Heritage List. There are a number of public holidays in Germany determined by each state; 3 October has been a national day of Germany since 1990, celebrated as the Tag der Deutschen Einheit (German Unity Day).
Sources: en.wikipedia.org
== History == Methylene blue has been described as "the first fully synthetic drug used in medicine". Methylene blue was first prepared in 1876 by German chemist Heinrich Caro. Its use in the treatment of malaria was pioneered by Paul Guttmann and Paul Ehrlich in 1891. During this period before World War I, researchers like Ehrlich believed that drugs and dyes worked in the same way, by preferentially staining pathogens and possibly harming them. Changing the cell membrane of pathogens is how various drugs work, so the theory was partially correct, although far from complete. Methylene blue continued to be used in World War II, where it was not well-liked by soldiers, who observed, "Even at the loo, we see, we pee, navy blue." It was discovered to be an antidote to carbon monoxide poisoning and cyanide poisoning in 1933 by Matilda Brooks. Methylene blue was the original prototype or lead compound for the design of many antimalarials including chloroquine, antihistamines, and antipsychotics including chlorpromazine.
Flexible linkers may consist of many small glycine residues, giving them the ability curl into a dynamic, adaptable shape. Rigid linkers may be formed of large, cyclic proline residues, which can be helpful when highly specific spacing between domains must be maintained. In vivo cleavable linkers are unique in that they are designed to allow the release of one or more fused domains under certain reaction conditions, such as a specific pH gradient, or when coming in contact with another biomolecule in the cell.
== Applications == Since the early 20th century electron ionization has been one of the most popular ionization techniques because of the large number of applications it has. These applications can be broadly categorized by the method of sample insertion used. The gaseous and highly volatile liquid samples use a vacuum manifold, solids and less volatile liquids use a direct insertion probe, and complex mixtures use gas chromatography or liquid chromatography.
== Classification == The MEROPS protease classification system counts 14 superfamilies plus several currently unassigned families (as of 2013) each containing many families. Each superfamily uses the catalytic triad or dyad in a different protein fold and so represent convergent evolution of the catalytic mechanism. For superfamilies, P indicates a superfamily containing a mixture of nucleophile class families, and C indicates purely cysteine proteases. Within each superfamily, families are designated by their catalytic nucleophile (C denoting cysteine proteases).
=== Standard addition === The method of standard addition is used in instrumental analysis to determine the concentration of a substance (analyte) in an unknown sample by comparison to a set of samples of known concentration, similar to using a calibration curve. Standard addition can be applied to most analytical techniques and is used instead of a calibration curve to solve the matrix effect problem.
Sources: en.wikipedia.org
=== Preservation === Archaeological work at Flag Fen is ongoing. Extensive drainage of the surrounding area, which benefits agriculture, means that many of the timbers are drying out and are threatened with destruction by such exposure. One section of poles is being preserved by replacing the cellulose in the wood with water-carried wax, impregnating the wood over the years. This technique is also being used to preserve Seahenge and the Hassholme Boat. Another preservation technique used for timbers found at the site is freeze drying. A well-organised visitor centre, the Flag Fen Bronze and Iron Age Centre, has been constructed there with a museum and exhibitions. In the preservation hall one section of the timbers is preserved in situ and prevented from drying out by misting with water. Also at the site are reconstructions of two Bronze Age roundhouses and one from the Iron Age. A section of the Roman road known as the Fen Causeway has been exposed and crosses the site. In addition there is a reconstruction of a prehistoric droveway used for moving livestock.
Glucagon binds to the glucagon receptor, a G protein-coupled receptor, located in the plasma membrane of the cell. The conformation change in the receptor activates a G protein, a heterotrimeric protein with αs, β, and γ subunits. When the G protein interacts with the receptor, it undergoes a conformational change that results in the replacement of the GDP molecule that was bound to the α subunit with a GTP molecule. This substitution results in the releasing of the α subunit from the β and γ subunits. The alpha subunit specifically activates the next enzyme in the cascade, adenylate cyclase.
== Development of penicillin derivatives == The narrow range of treatable diseases or "spectrum of activity" of the penicillins, along with the poor activity of the orally active penicillin V, led to the search for derivatives of penicillin that could treat a wider range of infections. The isolation of 6-APA, the nucleus of penicillin, allowed for the preparation of semisynthetic penicillins, with various improvements over benzylpenicillin. Ampicillin was developed by the Beecham Research Laboratories in London. When introduced to clinical use in 1961 it was the first semisynthetic penicillin that could be taken orally that was effective against both Gram-negative and Gram-positive bacteria, whereas the original was only effective against Gram-positive.
==== Hadi makes inroads ==== National reconciliation talks were held with the participation of many separatist elements, as well as the Houthis. Nine years after the death of Hussein Badreddin al-Houthi, the Yemeni government turned over the remains of the Houthi patriarch to his family and he was buried in northern Yemen in June 2013, with a representative of the Hadi administration in attendance. Hadi visited the United States, a key overseas ally, in July 2013. The U.S. also lifted a ban on transferring detainees from its Guantanamo Bay detention camp in Cuba to Yemen. Meanwhile, Saudi Arabia deported as many as 300,000 to 400,000 Yemeni migrant workers to their home country during 2013, causing an influx of poor, landless Yemenis into northern Yemen.
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.
Semax is based on the ACTH(4-10) fragment, a seven-amino-acid segment of adrenocorticotropic hormone. The synthetic peptide retains the core sequence while removing regions associated with endocrine activity. This modification is intended to isolate effects on the nervous system.