RP-HPLC is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Last reviewed on 2026-07-28. Where a claim depends on a specific study, the study is described rather than over-claimed.
Published work on this compound consists mainly of in vitro experiments, animal studies, and small clinical investigations, a substantial share of which appeared in Russian-language journals. Sample sizes are generally small, control conditions differ between studies, and several endpoints rely on markers whose clinical meaning is itself debated. Reviews of the longevity field treat the peptide as an early example of telomerase-directed research rather than an established intervention. Regulatory treatment varies by country: some jurisdictions place it under prescription controls, others treat it as a laboratory material, and importation may be restricted regardless of local status.
Epitalon is a synthetic tetrapeptide whose sequence is alanine–glutamate–aspartate–glycine, commonly abbreviated AEDG. It was developed in Russia during the 1980s and 1990s by investigators associated with the St. Petersburg Institute of Bioregulation and Gerontology, who studied short peptides as regulators of gene expression and tissue function. The alternative spelling epithalon appears interchangeably in the literature, and the two names refer to the same molecule. Outside Russia it is encountered chiefly as a research chemical rather than a licensed medicine, and it holds no approval from the United States Food and Drug Administration or the European Medicines Agency.
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.
| Property | Value | Notes |
|---|---|---|
| Peptide sequence | Ala-Glu-Asp-Gly | Often abbreviated AEDG in research literature |
| Common synonyms | Epithalon, epitalon, AEDG | Spelling variants refer to the same tetrapeptide |
| Molecular formula | C14H22N4O9 | Theoretical monoisotopic mass near 390.35 Da |
| Appearance | White to off-white powder | Typically supplied as a lyophilised solid |
| Solubility class | Freely soluble in water | Hydrophilic peptide; dissolves in aqueous buffer |
Several names circulate for the same molecule, including epitalon, epithalone, epithalamin tetrapeptide, and the sequence code AEDG. A CAS registry number, 307297-39-8, is commonly cited for it, though catalogue entries should be checked against supplier documentation because mislabelled records occur. In its usual form the peptide carries free amino and carboxyl termini and is neither glycosylated nor lipidated. Researchers distinguish the defined tetrapeptide from epithalamin itself, a crude pineal preparation containing many peptides that is not chemically characterised.
Material supplied for laboratory use is normally a lyophilised white to off-white powder that dissolves readily in water and in isotonic saline. Lyophilised cakes are hygroscopic and should be equilibrated to room temperature before opening to limit condensation on the solid. Solutions are typically prepared at milligram-per-millilitre concentrations and divided into single-use aliquots, because repeated freeze–thaw cycles degrade short peptides. Aqueous solutions are far less stable than the dry powder, and identity is usually verified by mass spectrometry alongside purity estimation from reversed-phase high-performance liquid chromatography.
Epitalon is a synthetic linear tetrapeptide with the sequence alanine–glutamate–aspartate–glycine, abbreviated AEDG. Its molecular formula is C14H22N4O9 and the calculated mass is approximately 390.35 g/mol. The compound is made by solid-phase peptide synthesis rather than extracted from tissue, although early work described it as a short fragment of a peptide fraction obtained from bovine pineal extract. In the research literature the spelling epitalon and the variant epithalone both appear, while AEDG is the standard code used in peptide nomenclature.
Because epitalon has no pharmacopoeial monograph, quality assessment depends on supplier documentation and independent testing. Certificates of analysis typically report a purity figure from a single chromatographic run, a measured mass and sometimes an appearance description, but methods and acceptance criteria are not harmonised across vendors. Third-party laboratories can repeat identity and purity measurements, and mismatches between labelled and measured peptide content have been described for research peptides generally. What constitutes adequate identity confirmation for a molecule of this size stays an open question, since mass agreement alone does not separate closely related sequences.
Identity testing for epitalon relies on reversed-phase high-performance liquid chromatography for purity and mass spectrometry for mass confirmation. Because the sequence contains no tryptophan or tyrosine, ultraviolet detection at 280 nanometres is insensitive, so chromatographic methods usually monitor absorbance near 214 nanometres, where the peptide backbone absorbs. Electrospray ionisation or matrix-assisted laser desorption/ionisation then checks the intact mass against the expected value near 390 daltons. Peptide mapping or amino acid analysis after acid hydrolysis can supplement these measurements, although such confirmatory work is seldom reported on commercial certificates of analysis.
In its supplied form epitalon is a white to off-white powder, usually lyophilized and often hygroscopic. It dissolves readily in water and in aqueous buffers, and it is commonly handled as the acetate or trifluoroacetate salt to improve stability during purification and drying. The amide backbone is labile in aqueous media, so solutions are less durable than the dry solid. Handling notes in the chemical literature therefore emphasize keeping the powder dry, cool and shielded from light until it is dissolved.
Epitalon is a synthetic tetrapeptide whose sequence is alanine-glutamate-aspartate-glycine, written in single-letter code as AEDG. The four residues are joined by three peptide bonds, giving a linear backbone with no branching and no disulfide bridges. Its calculated molecular mass for the free form is approximately 390.3 daltons, a figure that rises when the compound is supplied as an acetate or trifluoroacetate salt. Because the chain is short, the molecule is defined entirely by its residue order rather than by any folded three-dimensional structure.
Dissolution is usually performed in water or a suitable aqueous buffer, and the resulting liquid is divided into single-use portions before freezing. Freeze-thaw cycling is a recognised source of loss for short peptides, since each cycle can encourage aggregation or adsorption onto container walls. Working solutions are generally kept cold and used within a short window, although published stability data specific to epitalon are thin. Containers should be marked with concentration and date, and solutions examined for cloudiness before use.
Identity is normally established by reversed-phase high-performance liquid chromatography combined with mass spectrometry, a pairing that separates components and confirms molecular mass at once. Purity is quoted as a percentage from the chromatogram, and figures above ninety-five percent are a frequent commercial specification. Amino acid analysis or sequencing supplies further confirmation when required. Because many short peptides behave similarly under chromatography, retention time alone does not establish sequence; the mass measurement is what separates one tetrapeptide from another, and certificates should report both.
Short peptides such as AEDG are normally supplied as a freeze-dried solid and are kept dry, cold, and shielded from light. Holding at minus twenty degrees Celsius is common for the long term, while a refrigerator suffices for brief periods before use. The material takes up moisture to some degree, so containers should stay sealed and be allowed to reach room temperature before opening, which limits condensation on the contents. Repeated warming and cooling of a single container is discouraged because it admits water and can lower the amount of intact peptide.
==== Tax base erosion and the Digital Services Tax ==== The repatriation of AI-generated profits to the US poses a direct threat to the UK tax base. The Fair Tax Foundation's 2025 report on the "Silicon Six" (Alphabet, Amazon, Apple, Meta, Microsoft, and Netflix) found that over the past decade, these companies generated $11 trillion in revenue but paid an effective global corporate tax rate of just 18.8% (falling to 16.1% if one-off repatriation payments are excluded). The report highlighted that aggressive profit-shifting to low-tax jurisdictions means overseas revenue is subject to much lower tax rates than US-booked domestic revenue. To counter this, the UK introduced a Digital Services Tax (DST), a 2% levy on the revenues of search engines, social media services, and online marketplaces. Because it taxes turnover rather than easily shifted profits, the DST is relatively effective, raising £944 million in 2025 alone and projected to raise up to £5.2 billion over the current Parliament. However, the DST has become a major geopolitical flashpoint. US President Donald Trump has repeatedly threatened to impose punitive tariffs on UK exports unless the tax is scrapped, describing such levies as "overseas extortion". Think tanks such as Chatham House and the Royal United Services Institute (RUSI) have warned that if the UK government trades away the DST to secure US tech investment or avoid tariffs, it would surrender crucial regulatory power and signal a profound loss of digital sovereignty over the foundational infrastructure of the modern economy.
== Contraindications == Like other AASs, oxandrolone may worsen hypercalcemia by increasing osteolytic bone resorption. When taken by pregnant women, oxandrolone may have unintended effects such as masculinization on the fetus.
=== Scraped surface generators === The world’s first patent for a slurry ice generator was filed by Sunwell Technologies Inc. of Canada in 1976. Sunwell Technologies Inc. introduced slurry ice under the trade name deepchill ice, in the late 1970s. Slurry ice is created through a process of forming spherical ice crystals within a liquid. The slurry ice generator is a scraped-surface vertical shell and tube heat exchanger. It consists of concentric tubes with refrigerant flowing between them and the water/freezing point depressant solution in the inner tube. The inner surface of the inner tube is wiped using a mechanism which in the original Sunwell design consists of a central shaft, spring-loaded plastic blades, bearings, and seals. The small ice crystals formed in the solution near the tube surface are wiped away from the surface and mixed with unfrozen water, forming the slurry. Other slurry ice generators adapted the first idea of wiping the surface using an auger originally designed to create flake ice. Wipers also can be brushes or fluidized bed heat exchangers for ice crystallization. In these heat exchangers, steel particles circulate with the fluid, mechanically removing the crystals from the surface. At the outlet, steel particles and slurry ice are separated.
===== Houthis ===== In March 2025, the U.S. began a series of airstrikes on Houthi targets in Yemen to counter attacks on Red Sea shipping, with the goal of restoring freedom of navigation and deterring further aggression. U.S. officials accidentally included The Atlantic editor Jeffrey Goldberg in a Signal group chat discussing the military plans, sparking a political scandal and accusations of risking national security and violating records-preservation laws. In May 2025, Trump announced that his administration had reached a ceasefire deal with the Houthis.
In 2013, Chinese authorities announced that, since 2007, GSK had funnelled HK$3.8 billion in kickbacks to GSK managers, doctors, hospitals and others who prescribed their drugs, using over 700 travel agencies and consulting firms. Chinese authorities arrested four GSK executives as part of a four-month investigation into claims that doctors were bribed with cash and sexual favours. In 2014, a Chinese court found the company guilty of bribery and imposed a fine of US$490 million. Mark Reilly, the British head of GSK's Chinese operations, received a three-year suspended prison sentence after a one-day trial held in secret. Reilly was reportedly deported from China and dismissed by the company.
Sources: en.wikipedia.org
=== Associative ionization === Associative ionization is a gas phase reaction in which two atoms or molecules interact to form a single product ion. One or both of the interacting species may have excess internal energy. For example,
=== Effect on diet and lifestyle === The refrigerator allows households to keep food fresh for longer than before. The most notable improvement is for meat and other highly perishable wares, which previously needed to be preserved or otherwise processed for long-term storage and transport. This change in the supply chains of food products led to a marked increase in the quality of food in areas where refrigeration was being used. Additionally, the increased freshness and shelf life of food caused by the advent of refrigeration in addition to growing global communication methods has resulted in an increase in cultural exchange through food products from different regions of the world. There have also been claims that this increase in the quality of food is responsible for an increase in the height of United States citizens around the early 1900s. Refrigeration has also contributed to a decrease in the quality of food in some regions. By allowing, in part, for the phenomenon of globalization in the food sector, refrigeration has made the creation and transportation of ultra-processed foods and convenience foods inexpensive, leading to their prevalence, especially in lower-income regions. These regions of lessened access to higher quality foods are referred to as food deserts. Freezers allow people to buy food in bulk and eat it at leisure, and bulk purchases may save money. Ice cream, a popular commodity of the 20th century, could previously only be obtained by traveling to where the product was made and eating it on the spot. Now it is a common food item.
and Afghan National Army soldiers led by SSG Robert James Miller was conducting a combat reconnaissance patrol through the Gowardesh Valley, Kunar Province, when they engaged a force of 15–20 insurgents occupying prepared fighting positions. After calling in close air support, Staff Sergeant Miller led a small squad forward to conduct battle damage assessment when over 100 insurgents ambushed the squad, Miller displayed extraordinary valor by drawing fire away from his squad, killing 10 insurgents in the process. His actions cost him his life, but he saved the lives of 7 members of his team and 15 Afghan National Army soldiers, he was awarded the Medal of Honor. In September 2008, a Green Beret ODA conducted a joint operation with 1 Troop 3 Squadron SASR in northwest Uruzgan Province, the operation was designed to lure insurgents into a trap using a ground convoy of five special forces GMV trucks as bait. SASR sniper teams, who inserted on foot the night before as part of two cut-off groups to overwatch the patrol. The plan worked, a small group of insurgents approached the vehicles, intent on ambushing the convoy, they were engaged by the SASR snipers. Minutes later a Toyota Hilux appeared carrying a number of armed insurgents, they were engaged and killed and a second vehicle, a van, arrived carrying 3 insurgents were engaged by the sniper teams until they spotted a female non-combatant who was used as a human shield by the surviving insurgent, the insurgent was eventually killed with no harm to the woman, a total of 13 insurgents were killed.
== Career == After her PhD, Chutia continued her research at Dibrugarh University for another year as a CSIR-postdoctoral fellow. She entered the field of plasma physics at the Physical Research Laboratory in Ahmedabad and then joined the Institute for Plasma Research in Gandhinagar. She then returned to the Institute of Advanced Study in Science and Technology as a faculty member and set up the Plasma Physics Laboratory. After finishing a fellowship awarded by the Japanese government in 1988 to work at the Plasma Laboratory of the Institute of Space and Astronautical Science, Tokyo, in 2005 she became the director of the Institute of Advanced Study in Science and Technology.
Sources: en.wikipedia.org
Epitalon is a synthetic four-amino-acid peptide with the sequence alanine–glutamate–aspartate–glycine, also written AEDG. It was developed in Russian gerontology research and is studied for proposed effects on telomerase, melatonin regulation, and neuroendocrine function. It is not an approved pharmaceutical in the United States or the European Union.
No. Epithalamin is a peptide-rich extract prepared from bovine pineal glands, while epitalon is a short synthetic peptide designed as a defined analogue of it. The synthetic version was intended to provide a reproducible molecule with some of the same proposed biological activity.
Telomere elongation and telomerase activation have been reported in cultured human somatic cells, but evidence from living human subjects is limited and has not been independently confirmed at scale. Reported findings come largely from small studies with differing designs, so the question remains open rather than settled.
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.