Everything below concerns epithalamin. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-06-01. Numbers and descriptions here follow the published literature rather than marketing material.
Residue composition is the property that most cleanly separates verified material from mislabelled samples. Alanine, glutamate, aspartate and glycine appear in that order from the N-terminus, and the two acidic residues sit in the middle of the chain. Because the peptide is short, it can be produced by solid-phase synthesis and characterised by mass spectrometry without ambiguity. Any reported sample whose measured mass departs substantially from 390 daltons is a different compound or a degraded mixture rather than epitalon.
Epitalon is a synthetic tetrapeptide whose four residues are alanine, glutamate, aspartate and glycine, commonly abbreviated AEDG. Its molecular formula is C14H22N4O9 and its monoisotopic mass is near 390.35 daltons. The peptide carries two acidic side chains, so it is neutral to negatively charged in most aqueous buffers. Published reference summaries usually list it under both spellings, epitalon and epithalon, and treat the two names as the same material.
Verification of research-grade material involves comparing a supplier chromatogram against an in-house reference, checking the observed mass against the calculated value, and where possible confirming residue order by tandem mass spectrometry or enzymatic peptide mapping. Purity claims should be read alongside the method used to obtain them, because detection wavelength and integration settings alter the result. Batch-specific data, rather than a generic grade statement, is the informative part of a certificate.
Identity and purity of epitalon samples are normally established by reversed-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres, combined with mass spectrometry. The mass spectrum confirms the expected molecular ion and can reveal truncated or oxidised by-products. Amino acid analysis after acid hydrolysis verifies that the four residues are present in the expected ratio. Certificates typically report a purity figure taken from chromatographic peak area, expressed as a percentage of total integrated signal.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C14H22N4O9 | Derived from the four constituent residues |
| Molecular mass | About 390.35 Da | Monoisotopic value, confirmed by mass spectrometry |
| Residue sequence | Ala-Glu-Asp-Gly | Read from the N-terminus to the C-terminus |
| Common synonyms | Epithalon; AEDG | Both forms appear in reference catalogues |
| Net charge near neutral pH | Negative | Two acidic side chains give a low isoelectric point |
The four residues give epitalon a molecular formula of C14H22N4O9 and a molecular weight near 390.35 daltons. The presence of two acidic residues, glutamate and aspartate, makes the free peptide strongly acidic, while the alanine and glycine ends provide neutral, nonpolar character. This combination produces a molecule with substantial water solubility. Because there are no cysteine, methionine, or tryptophan residues, the peptide lacks the most common oxidation-sensitive side chains, which simplifies handling compared with many longer peptides.
The proposed relationship between epitalon and pineal function is a central part of its background. Khavinson's group reported that short peptides corresponding to regions of larger pineal proteins could influence gene expression in cells. Epitalon was framed as a synthetic analogue of an active fragment rather than a direct isolation product. Whether the tetrapeptide reproduces the effects of the parent extract is an open question, because comparative studies are limited and the parent extract itself is not a single defined substance.
Interest in epitalon is usually discussed within the broader field of short peptide bioregulators, a category that includes other synthetic di-, tri-, and tetrapeptides studied by the same research group. These compounds share a common rationale: that small fragments of tissue-derived proteins can retain biological activity and can be produced reproducibly. The category as a whole remains outside mainstream pharmacological consensus, and epitalon specifically has a limited presence in independent, non-Russian research literature, which shapes how its evidence base is described.
Freeze-dried epitalon is normally kept at minus twenty degrees Celsius in a sealed, desiccated container, protected from light. Short excursions at ambient temperature during shipping are generally tolerated, but repeated warming and cooling cycles encourage moisture uptake, which shortens shelf life. Once dissolved, the peptide is far less stable than the solid: aqueous solutions are subject to hydrolysis and to deamidation at the aspartate and glutamate residues. Working solutions are therefore held refrigerated and used within days, and repeated freezing and thawing of the same vial is best avoided.
Identity and purity are checked by reversed-phase high-performance liquid chromatography, usually with ultraviolet detection near 214 nanometres, where the peptide bond absorbs. Mass spectrometry confirms the expected mass and reveals whether truncation products or adducts are present. Acid hydrolysis followed by amino acid analysis gives the residue ratio, which should approximate one alanine, one glutamate, one aspartate and one glycine. Counter-ions such as acetate or trifluoroacetate remain in the dried product and lower net peptide content, so a stated purity figure on a label does not by itself describe how much peptide a vial holds.
Epitalon is a synthetic tetrapeptide with the residue sequence alanine-glutamate-aspartate-glycine, commonly abbreviated AEDG. Its monoisotopic mass is approximately 390.35 daltons, and it is usually supplied as a lyophilised trifluoroacetate or acetate salt. The compound was derived from a pineal gland extract called epithalamin, a heterogeneous preparation investigated in the former Soviet Union. Researchers associated with the Saint Petersburg Institute of Bioregulation and Gerontology described the tetrapeptide as a constituent fragment of that extract. Commercial material is offered as a laboratory reagent rather than as a finished pharmaceutical product.
Literature searches for this compound must account for several spelling variants. Indexing databases contain epitalon, epithalon, epithalone, and AEDG, and relevant records are scattered across Russian-language and English-language journals that do not consistently cross-cite. Early publications describe the parent extract as a mixture of many peptides, whereas later work addresses the single synthetic tetrapeptide. That shift in nomenclature complicates comparison between studies, because extract data and tetrapeptide data are sometimes cited interchangeably. A search strategy omitting the alternate spellings will return an incomplete set of references.
Reported biological findings come mainly from cell culture and rodent experiments. Those studies describe changes in telomerase catalytic subunit expression, melatonin rhythm amplitude, and antioxidant enzyme activity after peptide exposure. Human data are sparse and consist of small trials with limited blinding and inconsistent endpoints. The proposed mechanisms remain hypotheses rather than established facts, and there is no consensus on whether effects observed in animals carry over to people. Independent replication outside the original research groups is limited, which is a recognised gap in the published literature.
Reference material is normally supplied as a lyophilised powder in a sealed vial. Product literature typically recommends storage at minus twenty degrees Celsius or colder, protected from light and moisture. Freeze-thaw cycling is usually avoided because repeated condensation can introduce water into the vial. Working solutions are commonly prepared fresh, aliquoted, and kept cold for short periods rather than stored at ambient temperature. Labelling the date of opening helps track how long a vial has been in use.
Solubility is high in water, phosphate-buffered saline and normal saline, a pattern that follows from the two acidic residues in the chain. The peptide dissolves poorly in non-polar solvents such as hexane or chloroform. Stock solutions are often prepared in water first and then diluted into the buffer of interest. Because the molecule is small and hydrophilic, filtration through a low-protein-binding membrane is usually straightforward, and visible particulates are uncommon in freshly made solutions.
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During transport water needs to be maintained to a high quality, with regulated temperature, sufficient oxygen and minimal waste products. In some cases anaesthetics may be used in small doses to calm fish before transport. Aquaculture is sometimes part of an environmental rehabilitation program or as an aid in conserving endangered species.
The War of the Fifth Coalition ended with the Treaty of Schönbrunn (14 October 1809). In the east, only the Tyrolese rebels led by Andreas Hofer continued to fight the French-Bavarian army until finally defeated in November 1809. In the west, the Peninsular War continued. Economic warfare between Britain and France continued: The British continued a naval blockade of French-controlled territory. Due to military shortages and lack of organisation in French territory, many breaches of the Continental System occurred and the French Continental System was largely ineffective and did little economic damage to Great Britain. Both sides entered further conflicts in attempts to enforce their blockade. As Napoleon realised that extensive trade was going through Spain and Russia, he invaded those two countries; the British fought the United States in the War of 1812 (1812–1815). In 1810, the French Empire reached its greatest extent. Napoleon married Marie-Louise, an Austrian Archduchess, with the aim of ensuring a more stable alliance with Austria and of providing the Emperor with an heir (something his first wife, Joséphine, had failed to do). As well as the French Empire, Napoleon controlled the Swiss Confederation, the Confederation of the Rhine, the Duchy of Warsaw and the Kingdom of Italy. Territories allied with the French included:
Historically, terminal elimination half-lives were considered very long, 40–50 days for Hydroxychloroquine as compared to up to 60 days for Chloroquine. More recent studies suggest a shorter half-life of about 5 days. A long Hydroxychloroquine half-life is attributed to extensive tissue uptake rather than to an intrinsic inability to clear the drug. The expected delay in the attainment of steady-state concentrations (3–4 months) may be in part responsible for the slow therapeutic response observed with Hydroxychloroquine. Agents may be used in combination, however, people may experience greater side effects. Methotrexate is the most important and useful DMARD and is usually the first treatment. A combined approach with methotrexate and biologics improves ACR50, HAQ scores and RA remission rates. This benefit from the combination of methotrexate with biologics occurs both when this combination is the initial treatment and when drugs are prescribed in a sequential or step-up manner. Triple therapy consisting of methotrexate, sulfasalazine and hydroxychloroquine may also effectively control disease activity. Adverse effects should be monitored regularly with toxicity including gastrointestinal, hematologic, pulmonary, and hepatic. Side effects such as nausea, vomiting or abdominal pain can be reduced by taking folic acid. Rituximab combined with methotrexate appears to be more effective in improving symptoms compared to methotrexate alone. Rituximab works by decreasing levels of B-cells (an immune cell that is involved in inflammation).
Methanizer is an appliance used in gas chromatography (GC), which allows the user to detect very low concentrations of carbon monoxide and carbon dioxide. It consists of a flame ionization detector, preceded by a hydrogenating reactor, which converts CO2 and CO into methane CH4. Methanizers contain a hydrogenation catalyst to achieve this conversion. Nickel is commonly used as the catalyst and there are alternatives available.
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== Epidemiology == The current estimated global incidence annually is 20,000 to 50,000 people, though a large number of cases are believed to go unreported. Due to the limited habitats of ciguatoxin-producing microorganisms, ciguatera is common only in subtropical and tropical waters, particularly the Pacific and Caribbean, and usually is associated with fish caught in tropical reef waters. Exportation of reef fish, as well as tourism, often account for cases that develop in other regions. Ciguatoxin is found in over 400 species of reef fish. Avoiding consumption of all reef fish is the only sure way to avoid exposure. Imported fish served in restaurants may contain the toxin and produce illness which often goes unexplained by physicians unfamiliar with the symptoms of a tropical toxin. Ciguatoxin can also occur in farm-raised salmon. Furthermore, species substitution, labeling a reef fish as a non-reef fish at restaurants and retail, can complicate efforts by consumers to avoid ciguatera.
Piwi-interacting RNAs (piRNAs) are a recently discovered class of small non-coding RNAs (ncRNAs) with a length of 21–35 nucleotides. They play a role in gene expression regulation, transposon silencing, and viral infection inhibition. As stated by Monga and Banerjee in their primary report abstract, "Once considered as 'dark matter' of ncRNAs, piRNAs emerged as important players in multiple cellular functions in different organisms." In particular, as of 2019 they were characterised as not being siRNAs and as being responsible for the silencing of transposons.
Epithelium Photomicrographs Histology at KUMC epithel-epith02 Simple squamous epithelium of the glomerulus (kidney) Diagrams of simple squamous epithelium Histology at KUMC epithel-epith12 Stratified squamous epithelium of the vagina Histology at KUMC epithel-epith14 Stratified squamous epithelium of the skin (thin skin) Histology at KUMC epithel-epith15 Stratified squamous epithelium of the skin (thick skin) Stratified squamous epithelium of the esophagus Microanatomy Web Atlas
=== Organoeinsteinium compounds === Einsteinium's high radioactivity has a potential use in radiation therapy, and organometallic complexes have been synthesized in order to deliver einsteinium to an appropriate organ in the body. Experiments have been performed on injecting einsteinium citrate (as well as fermium compounds) to dogs. Einsteinium(III) was also incorporated into β-diketone chelate complexes, since analogous complexes with lanthanides previously showed strongest UV-excited luminescence among metallorganic compounds. When preparing einsteinium complexes, the Es3+ ions were 1000 times diluted with Gd3+ ions. This allowed reducing the radiation damage so that the compounds did not disintegrate during the 20 minutes required for the measurements. The resulting luminescence from Es3+ was much too weak to be detected. This was explained by the unfavorable relative energies of the individual constituents of the compound that hindered efficient energy transfer from the chelate matrix to Es3+ ions. Similar conclusion was drawn for americium, berkelium and fermium. Luminescence of Es3+ ions was however observed in inorganic hydrochloric acid solutions as well as in organic solution with di(2-ethylhexyl)orthophosphoric acid. It shows a broad peak at about 1064 nanometers (half-width about 100 nm) which can be resonantly excited by green light (ca. 495 nm wavelength). The luminescence has a lifetime of several microseconds and the quantum yield below 0.1%.
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==== NATO ==== The foreign secretary, Geoffrey Howe, spoke highly of Heseltine's contribution to NATO and WEU conferences. Heseltine was as angry as Thatcher at the US invasion of Grenada, a Commonwealth country. He wanted warmer relations with the Soviets and was sceptical about the US Strategic Defense Initiative ("Star Wars"), putting in a brief and grudging appearance at Caspar Weinberger's Ditchley Park Conference about the topic in 1985. Heseltine came close to misleading the House of Commons over the meeting of NATO defence ministers at Montebello, Quebec, in October 1983. He stated that no "specific" proposals had been made to update NATO short range and tactical nuclear weapons. In fact a decision had been made in principle to do so. Crick describes Heseltine's answers as "highly disingenuous and deceitful". At the time NATO was claiming to be cutting back on such weapons, and the peace movement was still powerful in Germany where such weapons might be used.
== External links == HPRD Human Protein Reference Database, a (manually) curated database of human protein information with visualization tools IntAct Interaction Database, a public repository for manually curated molecular interaction data from the literature DIP Database of Interacting Proteins, a manual and automatic catalog of experimentally determined interactions between proteins MIPS Mammalian Protein–Protein Interaction Database, the MIPS mammalian protein–protein interaction database
The beta blocker pindolol has been found to robustly potentiate the effects of DMT. This is thought to be due to pindolol's serotonin 5-HT1A receptor antagonism, which is thought to disinhibit the effects of DMT. The serotonin receptor agonist methysergide (UML-491) has been reported to greatly intensify the effects of DMT.
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It is a four-amino-acid peptide built from alanine, glutamate, aspartate and glycine in that order. Its formula is C14H22N4O9, and it is made by chemical synthesis rather than extracted from tissue. The synthetic peptide is a single defined molecule, unlike the pineal extracts it is often compared with.
No. The two spellings refer to the same tetrapeptide, and the difference reflects transliteration from Russian. Laboratories and catalogues use both forms interchangeably. The material is also indexed as AEDG, taken from the one-letter codes of its residues.
Epithalamin is a mixed preparation derived from animal pineal tissue and contains many peptides. Epitalon is one synthetic sequence chosen for study from that broader mixture. Statements about one do not transfer directly to the other.
The usual approach is reversed-phase HPLC with ultraviolet detection, reported as a percentage of total peak area. Mass spectrometry is used alongside chromatography to confirm identity rather than purity alone.