A practical reference on ACTH fragment: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-06-04. Anything still debated is marked as such rather than presented as settled.
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.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Typical purity | 95% or higher | By reversed-phase HPLC area |
| Identity method | Electrospray mass spectrometry | Confirms molecular mass |
| Purity method | Reversed-phase HPLC | Detection near 214 nm |
| Primary degradation | Methionine oxidation | Sulfoxide product, +16 Da |
| Solution storage | 2-8 °C, short term | Aliquot to avoid freeze-thaw |
Practical handling follows from those properties. Bulk material is best divided into single-use portions soon after receipt, because each thaw exposes the whole container to moisture and temperature cycling. Vials should be allowed to reach room temperature before opening to prevent condensation on the powder. Low-binding plasticware reduces loss of dilute solutions, and sterile filtration is used when a preparation must remain free of microbial growth. Records of batch number, reconstitution date and storage history are what allow a later analytical result to be interpreted meaningfully.
Identity and purity of Semax are established mainly by reversed-phase high-performance liquid chromatography coupled with mass spectrometry. The chromatographic trace gives a purity estimate as a percentage of total peak area, while electrospray or matrix-assisted laser desorption ionization confirms the molecular mass against the calculated value. Amino acid analysis and sequence-specific fragmentation provide further confirmation when a supplier's chain of custody is unclear. Vendors frequently quote a purity figure without stating the detection wavelength or the integration method, which limits how far one number can be compared with another.
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.
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.
==== Impact on growers ==== The US-supported coca eradication policy has been criticized for its negative impact on the livelihood of South American coca growers, in a region where the coca leaf has traditionally been chewed and used in tea and for religious, medicinal and nutritional purposes by locals Making traditional coca cultivation illegal is viewed as unjust. In areas where forced eradication also destroyed other food or market crops, without providing an alternative, farmers were left starving and destitute.
== Pharmacological modulation == Neutral endopeptidase (NEP) also known as neprilysin is the enzyme that metabolizes natriuretic peptides. Several inhibitors of NEP are currently being developed to treat disorders ranging from hypertension to heart failure. Most of them are dual inhibitors (NEP and ACE). In 2014, PARADIGM-HF study was published in NEJM. This study considered as a landmark study in treatment of heart failure. The study was double blinded; compared LCZ696 versus enalapril in patients with heart failure. The study showed lower all cause mortality, cardiovascular mortality and hospitalization in LCZ696 arm. Omapatrilat (dual inhibitor of NEP and angiotensin-converting enzyme) developed by BMS did not receive FDA approval due to angioedema safety concerns. Other dual inhibitors of NEP with ACE/angiotensin receptor are (in 2003) being developed by pharmaceutical companies.
In terms of possible research for Ullrich congenital muscular dystrophy one source indicates that cyclosporine A might be of benefit to individuals with this CMD type. According to a review by Bernardi, et al., cyclosporin A (CsA) used to treat collagen VI muscular dystrophies demonstrates a normalization of mitochondrial reaction to rotenone.
Collagen XXIII belongs to the transmembranous subfamily of collagens. Proteins which are included in this group present an amino-terminal cytoplasmic domain followed by a membrane-spanning hydrophobic domain and at least one extracellular triple-helical collagenous domain alternated with short non-collagenous domains. Collagens XIII, XVII, and XXV, and related proteins such as class A macrophage scavenger receptors, ectodysplasin A or the MARCO1 receptor, are also part of this group. An alternative name for this type of protein is MACITs (membrane-associated collagens with interrupted triple helices). Collagen XXIII shows structural homology with collagen XIII and collagen XXV . Apart from having the characteristic structure of transmembranous collagens, all three proteins present a high level of amino acid residue conservation in collagenous and non-collagenous domains. Collagens α1(XIII), α1(XXIII) and α1(XXV) display three collagenous domains (Col 1, Col 2, and Col 3) and four non-collagenous domains (NC1, which is also a transmembranous domain, NC2, NC3 and NC4). It has been reported that Col 1 domain of α1(XXIII) shows similarities with regions of both Col 1 and Col 2 domains of collagen types α1(XIII) and α1(XXV), whilst sequences of Col 2 and Col 3 domains of α1(XXIII) are related to the Col 3 domain of types α1(XIII)and α1(XXV). Short non-collagenous domains also exhibit similarities, especially in the NC1 and NC4 domains. Between 60 and 78% of the amino acid residues of these domains are identical in all three chains.
=== Fibroblast-populated skin substitutes === Fibroblast-populated Skin Substitutes are scaffolds which contain fibroblasts that are able to proliferate and produce extracellular matrix and growth factors within 2 to 3 weeks. This creates a matrix similar to that of a dermis. Commercially available types are for example:
Sources: en.wikipedia.org
In the reaction 234U + n → 235U reaction, the 234U content of 4.5% enriched fuel drops steadily over the irradiation period falling from 450g/ton HM to 205g/ton HM in fuel with an irradiation of 60GWd/ton HM. Additionally, (n, 2n) reactions with fast neutrons also convert small amounts of 235U to 234U. This is countered by the rapid conversion of available 234U into 235U through thermal neutron capture. Uranium from spent nuclear fuel may contain as much as 0.010% 234U, or 100 parts per million, lower than the original fuel but still a higher fraction than natural uranium's 55 parts per million. Depleted uranium separated during the enrichment process contains much less 234U (around 0.001%), which reduces the alpha radioactivity almost half (the beta and gamma activity, which is from 234Th and 234Pa, is unchanged) compared to natural uranium having an equilibrium concentration of 234U in which an equal number of decays of 238U and 234U occur. Uranium-234, as well as uranium-232, is a byproduct, through further neutron capture, in reactors breeding thorium-232 into uranium-233.
Arafat Jamal, the UNHCR Representative in Afghanistan, noted that they faced limited options amid the military confrontations between Afghanistan and Pakistan. According to The Guardian, the war has overshadowed the executions of political prisoners in Iran, including those involved in the mass protests of January 2026, allowing Iran to continue carrying out death sentences and other severe punishments with little international scrutiny. According to several Iran-focused human rights groups, the rate of sentencing and executions by hanging surged amidst the war. The groups state that in most of these cases, executed prisoners did not receive due process.
== History == On August 10, 1863, the Napa Valley Register first published. It was founded by J.I. Horrell as a pro-Union paper, in contrast to the pro-Succession Napa Echo. By 1864, the newspaper had dropped “Valley” from its name, becoming simply the Napa Register, until returning to the original name over a century later. Editor R.T. Montgomery retired from the paper in January 1866. He returned that May and sold it to N.E. White in January 1868. White left after six months and Montgomery returned again, only to later sell the Register a second time in November 1869 to R.D. Hopkins, formerly editor of the Vallejo Recorder. Hopkins sold to Rev. George W. Henning and George M. Francis in February 1872. The Register moved to daily publication in December 1872. Henning sold out to Charles A. Gardner in May 1873. Gardner left after a few years to run the St. Helena Star. George M. Francis became sole owner of the Register in 1878, upon the death of his business partner. Francis was succeeded in ownership by his son George H. Francis in 1932. The paper remained with Francis and various partners until 1958, when it was sold to Scripps League Newspapers. Scripps was acquired by Pulitzer in 1996, and Pulitzer was acquired by Lee Enterprises in 2005. Dan Evans became the paper's editor in March 2022, and he soon unveiled a newly reconstituted editorial board that October. The board was made up of three members of the newspaper's staff and seven community members. It aimed to assist in driving the official opinion of the paper. In April 2023, the paper laid off two employees.
The solubility of calcium sulfate decreases as temperature increases. This behaviour ("retrograde solubility") is uncommon: dissolution of most of the salts is endothermic and their solubility increases with temperature. The retrograde solubility of calcium sulfate is also responsible for its precipitation in the hottest zone of heating systems and for its contribution to the formation of scale in boilers along with the precipitation of calcium carbonate whose solubility also decreases when CO2 degasses from hot water or can escape out of the system.
In the final stage of elongation, called translocation, the deacylated tRNA (in the P site) and the dipeptidyl-tRNA (in the A site) along with its corresponding codons move to the E and P sites, respectively, and a new codon moves into the A site. This process is catalyzed by elongation factor G (EF-G). The deacylated tRNA at the E site is released from the ribosome during the next A-site occupation by an aminoacyl-tRNA again facilitated by EF-Tu. The ribosome continues to translate the remaining codons on the mRNA as more aminoacyl-tRNA bind to the A site, until the ribosome reaches a stop codon on mRNA(UAA, UGA, or UAG). The translation machinery works relatively slowly compared to the enzyme systems that catalyze DNA replication. Proteins in bacteria are synthesized at a rate of only 18 amino acid residues per second, whereas bacterial replisomes synthesize DNA at a rate of 1000 nucleotides per second. This difference in rate reflects, in part, the difference between polymerizing four types of nucleotides to make nucleic acids and polymerizing 20 types of amino acids to make proteins. Testing and rejecting incorrect aminoacyl-tRNA molecules takes time and slows protein synthesis. In bacteria, translation initiation occurs as soon as the 5' end of an mRNA is synthesized, and translation and transcription are coupled. This is not possible in eukaryotes because transcription and translation are carried out in separate compartments of the cell (the nucleus and cytoplasm).
Sources: en.wikipedia.org
Dry powder is normally held at -20 °C or lower, away from light and moisture. Sealed vials can also be kept at 2-8 °C for shorter intervals. Warming to room temperature before opening prevents condensation.
In solution, hydrolysis of peptide bonds and oxidation of the methionine residue are the principal concerns. Oxidation converts methionine to its sulfoxide form, shifting the mass by sixteen daltons. Both processes are slowed by cold storage and by avoiding alkaline conditions.
A certificate documents what the supplier measured on a specific lot, not how a laboratory will use the material. Independent verification of identity and purity is common practice. Acceptance criteria should be defined before a batch is ordered.
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.