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.
Last reviewed on 2026-06-29. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
The compound was developed in the 1980s at the Institute of Molecular Genetics in Moscow, where it emerged from research on short ACTH fragments and their effects on the central nervous system. Russian pharmaceutical listings describe it as a nootropic and neuroprotective agent, most often formulated as nasal drops. It is not a marketed medicine in the United States or the European Union, and no pharmacopoeial monograph covers it. Consequently, most published clinical experience with the substance originates from a small number of research centres, mainly in Russia and neighbouring countries.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its design combines the ACTH(4-7) core fragment with a C-terminal Pro-Gly-Pro extension, a modification intended to improve stability and prolong activity. The molecule is hydrophilic, carries no lipid chains or glycosylation, and has a theoretical mass just over 810 daltons in its free form. All seven residues are proteinogenic amino acids, so no non-natural building blocks appear in the backbone. A free N-terminal methionine and C-terminal proline define the unmodified parent peptide.
The compound was developed during the 1980s at the Institute of Molecular Genetics in Moscow as part of research on fragments of adrenocorticotropic hormone. Early work examined short ACTH-derived sequences that retained neurotrophic effects while lacking the endocrine activity of the full hormone. Semax entered clinical use in Russia during the 1990s, where it received registration for several neurological indications. Outside that region it remained primarily a laboratory research material rather than an approved therapeutic. English-language literature on it grew more slowly and frequently cited the original Russian studies.
Terminology around the compound varies by source. It appears in catalogues and papers as Semax, as the heptapeptide ACTH(4-7)-Pro-Gly-Pro, and under various alphanumeric laboratory codes used by individual suppliers. These names refer to the same sequence but may imply different salt forms, purity grades, or counter-ions. Peptide databases usually list the free base mass, while product descriptions sometimes report acetate or trifluoroacetate salts with a different formula weight. Because naming conventions for research peptides are not standardised across vendors, checking the declared sequence and measured mass is more reliable than relying on a trade name alone.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Free acid form of the heptapeptide; depends on terminal groups |
| Molecular mass | About 813.9 g/mol | Average mass used for mass spectrometry confirmation |
| Appearance | White to off-white solid | Supplied as a lyophilised powder; hygroscopic |
| Solubility class | Freely soluble in aqueous media | Water, saline, and phosphate buffers; limited organic solubility |
| Typical storage temperature | -20 degrees Celsius | Long term and dry; short working periods may use 2 to 8 degrees Celsius |
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 is a synthetic heptapeptide developed in the Soviet Union during the 1980s by researchers at the Institute of Molecular Genetics in Moscow. It was designed as a truncated analog of adrenocorticotropic hormone, retaining only the fragment spanning residues four through ten. Investigators sought a peptide that would preserve the cognitive effects associated with ACTH while eliminating the hormonal stimulation of the adrenal cortex. The compound entered clinical use in Russia during the following decade.
Russian regulatory authorities approved the peptide for nasal administration, and it remains listed in the national pharmacopoeia under several trade names. Documented indications include acute ischemic stroke, transient ischemic attacks, traumatic brain injury, and certain ophthalmological and neurological conditions. Physicians also prescribe it for cognitive complaints in older patients, although the evidence base for that use is thinner. Outside Russia and a few neighboring states, the substance is not an approved medicine and is sold instead as a research chemical.
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.
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.
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.
Each fission of a parent atom produces a different set of fission product atoms. However, while an individual fission is not predictable, the fission products are statistically predictable. The amount of any particular isotope produced per fission is called its yield, typically expressed as percent per parent fission; therefore, yields total to 200%, not 100%. (The true total is in fact slightly greater than 200%, owing to rare cases of ternary fission.) While fission products include every element from zinc through the lanthanides, the majority of the fission products occur in two peaks. One peak occurs at about (expressed by atomic masses 85 through 105) strontium to ruthenium while the other peak is at about tellurium to neodymium (expressed by atomic masses 130 through 145). The yield is somewhat dependent on the parent atom and also on the energy of the initiating neutron. In general the higher the energy of the state that undergoes nuclear fission, the more likely that the two fission products have similar mass. Hence, as the neutron energy increases and/or the energy of the fissile atom increases, the valley between the two peaks becomes more shallow. For instance, the curve of yield against mass for 239Pu has a more shallow valley than that observed for 235U when the neutrons are thermal neutrons. The curves for the fission of the later actinides tend to make even more shallow valleys. In extreme cases such as 259Fm, only one peak is seen; this is a consequence of symmetric fission becoming dominant due to shell effects.
== History == The company was founded by Jerry Cole and John Parmer in 1955 and took up shop in a 1,200-square-foot (110 m2) loft on West Illinois Street in downtown Chicago. In the 1960s, Cole-Parmer acquired Masterflex peristaltic pumps, followed shortly by the purchases of Gilmont Instruments and Manostat Pumps. They were acquired by Fisher Scientific, now Thermo-Fisher Scientific, in 2001. On July 17, 2014, Thermo Fisher Scientific Inc. agreed to sell one of its lab units, Cole-Parmer, to private-equity firm GTCR for $480 million in cash. The company has previously said its $13.6 billion acquisition of Life Technologies Corp. would allow it to cut costs while gaining from next-generation genetic-sequencing machines. It has also sought to expand in Asia-Pacific markets. In 2025, Cole-Parmer was sold to Brookfield Asset Management Ltd.'s private equity group and Caisse de dépôt et placement du Québec for a reported 1.4 billion dollars (USD).
It also has the largest Brazilian community in the UK; one of the largest Indian communities; a significant Afro-Caribbean community; and more recent Romanian, Polish and Somali communities. The 2021 census showed that 1.3% of adults in Brent identified as transgender, derived from the Census question, "Is the gender you identify with the same as your sex registered at birth?". This gave Brent the second highest proportion of transgender adults after the Borough of Newham (at 1.5%). The overall proportion in England and Wales was 0.5% with Brighton, an area well known for its LGBT communities, 1%. However, Prof Michael Biggs of Oxford University showed there was a correlation between the proportion of transgender people in these areas and the proportion for whom English was not their first language (34% in Brent and 35% in Newham, compared to 9% nationally), suggesting the question was not fully understood by some. Prof Biggs described the figures as "irredeemably flawed". In September 2024, Mary Gregory, a deputy director at the ONS said some people may have misunderstood the question, saying there was "potential bias" in how the question was answered "by those who responded that they had lower levels of English proficiency, some of whom may have mistakenly given an answer suggesting they were trans". As a result, the ONS downgraded the data from "accredited official statistics" to "official statistics in development" to reflect the possible flaws.
Sources: en.wikipedia.org
The use of C–H functionalization in the synthesis of lithospheric acid exemplifies the site- and stereoselective capabilities of using MPAA ligands in these reactions. As the penultimate step, the intermolecular C–H olefination introduces almost double the complexity into the compound enabling the highly convergent synthesis.
== Clinical data == In a 12 week randomised clinical trial, subjects receiving AOD9604 lost, on average, 1.8 kg more than those receiving placebo. Development of AOD9604 was halted following poor efficacy in a later 24 week trial.
LTE4 >> LTC4 = LTD4 > α-ketoglutarate = itaconate. It may be difficult to determine if an OXGR1-stimulating agent elicits a functional response by activating OXGR1 as opposed to some other mechanism. To make this distinction, studies have shown that the action of an OXGR1-activating agent on cultured cells, cultured tissues, or animals does not occur or is reduced when these cells, tissues, or animals have been altered so that they do not express or express greatly reduced levels of the OXGR1 protein, or when their actions are inhibited by an OXGR1 receptor antagonists. OXGR1 is inhibited by montelukast, a well-known inhibitor of the cysteinyl leukotriene receptor 1, i.e., the receptor for LTD4, LTC4, and LTE4. Montelukast also blocks the binding of these leukotrienes to, and thereby inhibits their activation of, OXGR1. One study presented evidence suggesting that α-ketoglutarate binds to OXGR1. It is assumed that montelukast similarly blocks α-ketoglutarate's binding to, and thereby inhibits its activation of OXGR1.
Sources: en.wikipedia.org
All three genes localize to chromosome 19q.13.3 in the order of FPR1, FPR2, and FPR3 to form a cluster which also includes the gene for another G protein-coupled chemotactic factor receptor, the C5a receptor (also termed CD88), which binds and is activated by complement component 5a (C5a) and GPR77, a second C5a anaphylatoxin chemotactic receptor C5a2 (C5L2), a second C5a receptor of debated function which has the structure of a G protein coupled receptor but fails to couple to G proteins. These points are of interest because C5a is generated by the interaction of bacteria with blood plasma components to activate the complement cascade which then cleave C5a from Complement component 5. Thus, bacteria produce a family of oligopeptide chemotactic factors plus activate host complement pathways to generate C5a, which, like the formylated oligopeptides, is a neutrophil chemotactic factor that operates through receptors whose genes cluster with those for the three formyl peptide receptors. Furthermore, bacteria-induced complement activation also causes the formation of complement component 3a (C3a) by cleavage from complement component 3; C3a is a neutrophil chemotactic factor which operates through a G protein coupled chemotactic factor receptor, the C3a receptor, whose gene is located at chromosome 12p13; C3a also acts through C5L2.
==== Circulatory system ==== The network of blood vessels include the great vessels (comprising large elastic arteries and large veins), other arteries (which carry blood away from the heart) and veins (which carry blood to the heart), smaller arterioles, and capillaries, which join with venules. Blood is a fluid consisting of plasma (comprising serum and clotting factors), red blood cells, white blood cells, and platelets. Components of the blood include nutrients (such as proteins and minerals), hemoglobin, hormones, and gases such as oxygen and carbon dioxide. These substances provide nourishment, help the immune system to fight diseases, and help maintain homeostasis through mechanisms such as thermoregulation, osmoregulation, and acid-base regulation. The circulatory system has two divisions, a systemic circuit (i.e. the left heart pumping oxygenated blood to the rest of the body (via the aorta) and into the right heart (via the venae cava)) and a pulmonary circuit (i.e. the right heart pumping deoxygenated blood to the lungs (via the pulmonary artery) and into the left heart (via the pulmonary vein)). In the human heart:
=== Organic carbon === The removal of organic carbon from water is one of the differentiators between deionized water and ultrapure water. Sources include bacteria, leaching from plastic piping, and dissolved atmospheric sources. Organic carbon can be removed using filtration by activated carbon and oxidation of organic carbon to carbon dioxide/bicarbonate.
Sources: en.wikipedia.org
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.
It appears in Russian pharmaceutical listings as a nasal formulation, but it is not an authorised medicine in the United States or the European Union. Outside those markets it is normally encountered as a research chemical rather than a prescription product.
Laboratory and animal work points to melanocortin signalling and changes in neurotrophic factor levels, especially brain-derived neurotrophic factor. The exact receptor targets and the degree to which these findings transfer to humans are still unresolved.
It is a synthetic seven-amino-acid peptide built from the ACTH(4-7) sequence plus a Pro-Gly-Pro tail. It belongs to the family of short ACTH fragments studied for nervous-system effects. Its backbone contains only standard amino acids.