The short version of tetrapeptide fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-05-31 and is reviewed periodically as new material appears.
Regulatory treatment differs by country. No formulation of epitalon holds a marketing authorisation as a medicine in the United States or the European Union, where material sold for laboratory use is handled as a research chemical and is not intended for human consumption. In Russia, several short peptide preparations from the same institute's peptide series are registered medicinal products, and epitalon appears in that national context. Elsewhere it is frequently offered as a cosmetic ingredient, a category with lighter requirements. Advertising claims about longevity or disease prevention are restricted in most jurisdictions, which limits how sellers describe the compound.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Storage temperature, solid | Approximately -20 C | Sealed, desiccated, protected from light |
| Typical identity method | Electrospray mass spectrometry | Protonated ion expected near 391 |
| Typical purity method | Reversed-phase HPLC | Ultraviolet detection near 214 nm |
| Common synonyms | Epithalon, epithalone, AEDG | Spelling variants appear in supplier catalogues |
| Solution stability | Days at 2-8 C | Hydrolysis and deamidation limit shelf life |
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.
Lyophilised epitalon is generally held at minus twenty degrees Celsius in a sealed container kept dry and dark. Cooler conditions are sometimes recommended for long-term archives. The solid takes up moisture readily enough that repeated opening of a vial introduces water, so dividing a batch into smaller portions before storage lowers degradation risk. Aqueous solutions are less durable than the dry powder and are usually prepared shortly before use, then kept cold and shielded from light to slow hydrolysis and oxidation.
The compound is generally described as a synthetic analogue of a fragment isolated from a pineal gland extract. Researchers associated with the Saint Petersburg Institute of Bioregulation and Gerontology introduced it during the 1980s and 1990s while studying short peptides from animal tissue. The original extract, called epithalamin, is a heterogeneous mixture, whereas epitalon is a single defined sequence. That distinction matters because findings reported for the extract are not automatically findings about the pure tetrapeptide, and claims about broader biological effects remain a separate question from the chemical identity described here.
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.
No pharmacopoeial monograph exists for this peptide, so quality rests on the supplier's internal specifications and on whatever independent testing a purchaser arranges. Certificates of analysis differ widely in which tests they report and in the limits applied. The counter-ion introduced during purification, commonly acetate or trifluoroacetate, changes the net peptide content of a given mass of powder, so two samples of equal weight may not contain equal amounts of the active sequence. Third-party laboratories can verify purity, identity, residual solvents, and counter-ion content for a fee, which makes documentation more informative than labelling.
Verification of a sample usually begins with reversed-phase high-performance liquid chromatography, which resolves the peptide from truncated sequences and other impurities and expresses purity as a percentage of total peak area. Mass spectrometry by electrospray ionisation or matrix-assisted laser desorption supplies an independent check, because the measured mass can be compared against the theoretical value for AEDG. Amino acid analysis or tandem mass spectrometry sequencing can confirm residue order. Each of these methods answers a different question: a purity figure does not establish identity, and an identity match does not establish how much of the material is intact peptide.
The most frequently cited proposed action is induction of telomerase, the enzyme that adds repeat sequences to chromosome ends. Cell-culture work from the originating group reported higher telomerase reverse transcriptase expression and measurable telomere elongation in human somatic cells after exposure. How a four-residue peptide would reach nuclear gene regulation is not established, and no cell-surface receptor or uptake route has been identified. Additional reports describe changes in melatonin secretion, antioxidant enzyme activity and lipid peroxidation in aged animals, but these findings remain mechanistically unconnected to the telomerase observation.
Published evidence comes mainly from Russian-language journals and from a single research group, with small sample sizes and limited independent replication. A few laboratories outside that group have examined related peptides and reported weaker or absent telomerase effects, so the central claim is best described as contested rather than settled. Rodent studies report modest changes in some ageing markers and in survival, but designs vary and control conditions are often sparse. No large randomised trial in humans has been published, and long-term safety data in healthy populations are correspondingly thin.
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A 2016 paper describes the efforts of how ansuvimab was originally developed as part of research efforts led by Dr. Nancy Sullivan at the United States National Institutes of Health Vaccine Research Center and Dr. J. J. Muyembe-Tamfum from the Institut National de Recherche Biomedicale (INRB) in the Democratic Republic of Congo. This collaborative effort also involved researchers from Institute of Biomedical Research and the United States Army Medical Research Institute of Infectious Diseases. A survivor from the 1995 outbreak of Ebola virus disease in Kikwit, Democratic Republic of Congo donated blood to the project that began roughly ten years after they had recovered. Memory B cells isolated from the survivor's blood were immortalized, cultured and screened for their ability to produce monoclonal antibodies that reacted with the glycoprotein of Ebola virus. Ansuvimab was identified from one of these cultures and the antibody heavy and light chain gene sequences were sequenced from the cells. These sequences were then cloned into recombinant DNA plasmids and purified antibody protein for initial studies was produced in cells derived from HEK 293 cells.
Several artificial nucleobases have been synthesized, and successfully incorporated in the eight-base DNA analogue named Hachimoji DNA. Dubbed S, B, P, and Z, these artificial bases are capable of bonding with each other in a predictable way (S–B and P–Z), maintain the double helix structure of DNA, and be transcribed to RNA. Their existence could be seen as an indication that there is nothing special about the four natural nucleobases that evolved on Earth. On the other hand, DNA is tightly related to RNA which does not only act as a transcript of DNA but also performs as molecular machines many tasks in cells. For this purpose it has to fold into a structure. It has been shown that to allow to create all possible structures at least four bases are required for the corresponding RNA, while a higher number is also possible but this would be against the natural principle of least effort.
== Natural occurrence == The half-life of thorium-232 (14 billion years) is more than three times the age of the Earth; thorium-232 therefore occurs in nature as a primordial nuclide. Other thorium isotopes occur in nature in much smaller quantities as intermediate products in the decay chains of uranium-238, uranium-235, and thorium-232. Some minerals that contain thorium include apatite, sphene, zircon, allanite, monazite, pyrochlore, thorite, and xenotime.
== History == Lente insulin arose from research into ways to alter the pharmacokinetics of bovine or porcine insulin products. Prior to the late 1940s, insulin products were derived from pork or beef sources, and then used virtually unaltered as "short-acting" insulin products. It was known by 1950 that the addition of protamine or zinc could alter the duration of action of these insulin products, and in 1952, K. Hallas-Møller at Novo Nordisk produced the first commercial insulin zinc suspension for use in humans. For decades, lente insulin was used as a basal insulin, designed to mimic the body's continual slow release of insulin throughout the day. Compared to NPH insulin, lente insulin has a similar but more protracted loss of action after a dose is administered. In the 1990s, recombinant DNA technology allowed for the mass production of the human insulin protein in yeast or bacteria. This led to formulations of recombinant lente human insulin products by the early 2000s. However, lente insulin began to fall out of favor with doctors in the mid-2000s, when insulin analogues such as glargine began to be approved. Insulin analogues made by recombinant DNA production methods have less variation in their strength and purity between doses and batches. Furthermore, while lente insulin (and NPH) have a definitive peak in effect, insulin analogs have a much less pronounced peak, making for more predictable effects and less risk of hypoglycemia.
Sources: en.wikipedia.org
=== 2009 === In February 2009, the International Institute for Strategic Studies published an annual report, Military Balance 2009. The report said that Russian forces were well-prepared for the August war and the Russian military operation was strategically well-planned. In 2009, Martin Malek, a researcher at the Institute for Peace Support and Conflict Management of the National Defense Academy in Vienna, noted that in September 2008, the Valdai Discussion Club was told by Vladimir Putin about his August 8 meeting with Chinese officials in Beijing and discussion of the recognition of Abkhazia and South Ossetia; Malek concluded that 8 August 2008 was the latest date when the recognition of Abkhazia and South Ossetia was considered or "possibly already decided". Malek concluded that due to the anti-American bias of the western Europeans and mass dislike of George W. Bush, the western media was keen to put the blame for the war on the pro-American Georgian government. In May 2009, Kaarel Kaas wrote an article for International Centre for Defense Studies, where he noted that this war was the first time since the fall of the Soviet Union that the Russian military had been used against an independent state, demonstrating Russia's willingness to use military force to attain its political objectives. Kaas wrote, "The military operation was only one phase in a longer-term anti-Georgian campaign.
Food and Drug Administration Food hygiene: example Clinical laboratory medicine: ISO 15198:2004 Clinical laboratory medicine—In vitro diagnostic medical devices—Validation of user quality control procedures by the manufacturer Engineering Engineering in general Engineering validation test Civil engineering Buildings – Roads – Bridges – Health care: example Greenhouse gas: ISO 14064 ANSI/ISO: Greenhouse gases – Requirements for greenhouse gas validation and verification bodies for use in accreditation or other forms of recognition Traffic and transport Road safety audit Periodic motor vehicle inspection Aircraft noise: example Aircraft: Model: (Ni-Cd) cells: example ICT Industry: example Accounting Agriculture – applications vary from verifying agricultural methodology and production processes to validating agricultural modeling Real estate appraisal – audit reporting and authentication Arms control
The first reported protein synthesized by KAHA ligation was human GLP-1 (7-36). Since then, a variety of small proteins (up to 200 residues) have been synthesized, including ubiquitin and other similar modifier proteins, hormone proteins, nitrophorin 4, S100A4 and cyclic proteins. C-terminal ketoacid monomers are pre-loaded on resin via a linker for Fmoc-SPPS (Fmoc-based solid phase peptide synthesis). Initial research utilised sulfur ylide linkers, but more recently the group developed acid- and photo-labile ketoacid monomers that can be loaded directly on Rink Amide resin. The most commonly used N-terminal hydroxylamine is the 5-oxaproline, which results in a homoserine residue after ligation and O-N rearrangement.
Mianserin, sold as Tolvon and other brand names, is an atypical antidepressant used primarily for treating depression in Europe and other countries. It is a tetracyclic antidepressant (TeCA) and is closely related to mirtazapine in terms of chemical structure, actions, and effects, although mianserin has greater noradrenergic activity and less 5-HT3 receptor antagonism.
Jesse Hutch as Evan Lee, a special forces veteran and longtime friend of Jeff who objects to some of Jeff's decisions and has to decide whether to remain loyal to him. Jill Wagner as Jacq Reynolds, a therapist who is pregnant and tries to help members of the Homestead grapple with their choices. She supports Jenna but rejects her religious faith. Manny McCord as Bing, a wild card security team member who leaves the Homestead and joins Raven Rock. Currie Graham as Blake Masterson, a city government official who asserts control of the city and sets up a FEMA camp. He shot Ian in the film and gathered FEMA operatives, gang members, and thugs to assemble a force to attack the Homestead. Ariel Llinas as Lieutenant Javi Espada, the Oakwood SWAT team leader who tries to urge Masterson to restraint but becomes more militant against the Homestead as events develop.
Sources: en.wikipedia.org
The solid is kept cold, dry and dark, typically at minus twenty degrees Celsius, in a sealed container with desiccant. Dissolved material is kept refrigerated and used promptly. Freezing and thawing a solution repeatedly is avoided because it accelerates degradation.
Reversed-phase chromatography with ultraviolet detection gives a purity percentage, while mass spectrometry confirms identity. Amino acid analysis checks the residue composition. Buyers typically request a certificate of analysis showing these measurements for the specific lot.
It is not authorised as a medicine in the United States or the European Union. Material is sold there as a research chemical or cosmetic ingredient. Some related short peptides are registered drugs in Russia, which is a distinct national situation rather than a general approval.
Epitalon is a synthetic tetrapeptide composed of four amino acids: alanine, glutamate, aspartate, and glycine. It is written as Ala-Glu-Asp-Gly. The free peptide has a molecular weight of about 390 daltons and is normally supplied as a lyophilized powder.