tetrapeptide comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Updated 2025-07-28. Numbers and descriptions here follow the published literature rather than marketing material.
The peptide is a synthetic analogue of epithalamin, a preparation extracted from bovine pineal glands. Investigators sought a short, chemically defined molecule that would reproduce some of the endocrine and gerontological observations attributed to the glandular extract. Proposed mechanisms centre on induction of telomerase activity, an effect reported in cultured human somatic cells in the early 2000s, together with influences on melatonin secretion and neuroendocrine regulation. Those mechanisms remain incompletely characterised, and the reported telomerase response has not been consistently reproduced by independent groups working in comparable systems.
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.
Storage recommendations center on limiting moisture, heat, and light. The dry powder is generally kept at minus 20 degrees Celsius, and some suppliers recommend minus 80 degrees for long-term archival. Once dissolved, solutions are usually aliquoted and frozen to avoid repeated freeze-thaw cycles, which can promote aggregation or degradation. Aqueous stability depends on pH and concentration, and buffered saline is often preferred over plain water for biological work. Stability data specific to epitalon remain limited, so general peptide-handling practices are applied by analogy rather than from product-specific validation.
Epitalon is a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, abbreviated AEDG. Its molecular formula is C14H22N4O9 and its calculated monoisotopic mass is approximately 390.35 daltons. The compound does not occur naturally as a free peptide; it is produced by solid-phase peptide synthesis. Because it contains two acidic residues and no basic residues, the neutral form carries a net negative charge at physiological pH. This charge profile influences how the peptide behaves in solution and during chromatographic analysis.
| 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 |
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.
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.
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.
The published literature is dominated by a small number of research groups, much of it in Russian-language journals, and independent replication outside those groups is limited. Studies are typically small, use cultured cells or rodent models, and report endpoints that differ between papers, which makes comparison difficult. Large randomised human trials have not appeared in the indexed literature. Questions about absorption, distribution and clearance are therefore still treated as open in reviews that mention the compound.
Epitalon is a synthetic tetrapeptide with the sequence alanine–glutamate–aspartate–glycine, commonly abbreviated AEDG. Its design traces to epithalamin, a peptide fraction prepared from bovine pineal gland extracts that researchers in Saint Petersburg began investigating in the 1970s. The compound has a molecular formula of C14H22N4O9 and a nominal molecular mass near 390 daltons. It holds no approved drug status in the United States or the European Union, and material sold under this name is generally offered as a research chemical rather than a finished pharmaceutical product.
Proposed mechanisms centre on cell-culture observations rather than a defined receptor interaction. Several reports describe increased expression of the telomerase catalytic subunit after exposure of cultured human cells, and the authors attributed the effect to short peptide fragments entering the nucleus and influencing gene transcription. No receptor for the tetrapeptide has been identified, and the free peptide is expected to be degraded rapidly by plasma peptidases. Whether any measurable fraction reaches intact tissues after administration remains an unresolved question rather than an established finding.
South Africa claimed 152 security-related incidents involving PLAN occurred in South West Africa that year, and acknowledged the combat deaths of 77 SADF and SWATF personnel. In July 1983 PLAN carried out its first major act of urban sabotage, detonating a bomb in the centre of Windhoek, which caused extensive property damage but no civilian injuries. Infiltration of Ovamboland and Kavangoland increased dramatically at around the same time, with 700 insurgents entering both regions. The SADF claimed to have killed or captured just under half the insurgents by May, but was unable to prevent the others from making their way further south. These developments indicated that PLAN had not lost its will to persevere despite the enormous materiel losses sustained during Protea, and the infiltration of men and supplies into South West Africa continued apace. Their confidence buoyed by the previous successful incursions into FAPLA-held territory, which had achieved marked success at only minimal cost in lives and materiel, Botha and his defence chiefs scheduled Operation Askari for December 1983. Like Protea, Askari was a major combined arms assault on PLAN base areas and supply lines in Angola; it also targeted nearby FAPLA air-defence installations and brigade headquarters. According to General Georg Meiring, commander of the SADF in South West Africa, Askari would serve the purpose of a preemptive strike aimed at eliminating the large numbers of PLAN insurgents and stockpiles of weapons being amassed for the annual rainy season infiltration.
Morpholino Also phosphorodiamidate Morpholino oligomer. A synthetic nucleic acid analogue connecting a short sequence of nucleobases into an artificial antisense oligomer, used in genetic engineering to knockdown gene expression by pairing with complementary sequences in naturally occurring RNA or DNA molecules, especially mRNA transcripts, thereby inhibiting interactions with other biomolecules such as proteins and ribosomes. Morpholino oligomers are not themselves translated, and neither they nor their hybrid duplexes with RNA are attacked by nucleases; also, unlike the negatively charged phosphates of normal nucleic acids, the synthetic backbones of Morpholinos are electrically neutral, making them less likely to interact non-selectively with a host cell's charged proteins. These properties make them useful and reliable tools for artificially generating mutant phenotypes in living cells.
== Etymology == The name derives from the Ancient Greek word πολύς (polus, meaning "many, much") and the word 'phenol' which refers to a chemical structure formed by attachment of an aromatic benzenoid (phenyl) ring to a hydroxyl (-OH) group (hence the -ol suffix). The term "polyphenol" has been in use at least since 1894.
=== 9 May === Two people were killed by Russian shelling in Nikopol. In Russia, the governor of Belgorod Oblast claimed that eight people were injured in a Ukrainian airstrike in Belgorod city. A drone attack on Krasnodar also set a fuel depot on fire. A drone strike was also reported in an oil refinery in Salavat in the first such incident of its kind in the constituent republic of Bashkortostan. The drone used in the attack on Bashkiria was conducted by a drone light aircraft, make unknown, that travelled some 1,500 km. The SBU arrested a resident of Kharkiv on suspicion of spying for Russia. It also claimed to have arrested several individuals in Kyiv on suspicion of attempting to set off bombs on behalf of Russia. Zelenskyy implemented a number of changes in the Ukrainian defense apparatus. He appointed Brigadier General Oleksandr Trepak as commander of the Ukrainian Special Operations Forces, replacing Colonel Serhii Lupanchuk. He also dismissed Valeriy Zaluzhnyi, former commander-in-chief of Ukraine's Armed Forces, from military service "on health grounds", and reappointed Dmytro Hereha as the commander of the Ukrainian Support Forces after replacing him with Oleksandr Yakovets in March 2024. Zelenskyy also dismissed Serhii Rud as director of the State Security Administration. Two colonels were also arrested after being accused of being agents for the Russian FSB. The US Army announced that it would supply three additional HIMARS units paid for by Germany to Ukraine.
The large amount of information processed in laboratories is managed by a system of software programs, computers, and terminology standards that exchange data about patients, test requests, and test results known as a Laboratory information system or LIS. The LIS is often interfaced with the hospital information system, EHR and/or laboratory instruments. Formats for terminologies for test processing and reporting are being standardized with systems such as Logical Observation Identifiers Names and Codes (LOINC) and Nomenclature for Properties and Units terminology (NPU terminology). These systems enable hospitals and labs to order the correct test requests for each patient, keep track of individual patient and specimen histories, and help guarantee a better quality of results. Results are made available to care providers electronically or by printed hard copies for patient charts.
Sources: en.wikipedia.org
==== Gamma Spectroscopy ==== Gamma spectroscopy yields results that are conceptually equivalent to alpha-particle spectroscopy, however, can result in sharper peaks due to reduced attenuation of energy. Some radionuclides produce discrete γ-rays that produce energy between a few KeV to 10 MeV which can be measured with a gamma-ray spectrometer. This can be accomplished without destroying the sample. The most common gamma-ray detector is a semiconductor germanium detector which allow for a greater energy resolution than alpha-particle spectroscopy, however gamma spectroscopy only has an efficiency of a few percent. Gamma spectroscopy is a less sensitive method due to low detector efficiency and high background. However, gamma spectroscopy has the advantage of having less time-consuming sample procedures and portable detectors for field use.
The Black Mesa Research Facility (also simply called Black Mesa) is a fictional large underground laboratory complex that serves as the primary setting for the video game Half-Life and its expansions, as well as its unofficial remake, Black Mesa. It also features in the wider Half-Life universe, including the Portal series. Located in the New Mexico desert in a decommissioned Cold War missile site, it is the former employer of Half-Life's theoretical physicist protagonist, Gordon Freeman, and a competitor of Aperture Science. While the facility ostensibly conducts military-industrial research, its secret experiments into teleportation have caused it to make contact with the alien world of Xen, and its scientists covertly study its life-forms and materials. In a catastrophic event known as the "Black Mesa Incident", an "anti-mass spectrometer" experiment conducted on Xen matter causes a Resonance Cascade disaster that allows aliens to invade Earth, and is the catalyst for the events of the series. Half-Life was critically acclaimed for its storytelling and level design. At the time, the integration of narrative into gameplay through scripted sequences and NPCs instead of through cutscenes was considered groundbreaking for a first-person shooter.
==== MeSH D12.125.068 – amino acids, basic ==== MeSH D12.125.068.050 – arginine MeSH D12.125.068.050.075 – argininosuccinic acid MeSH D12.125.068.050.095 – benzoylarginine-2-naphthylamide MeSH D12.125.068.050.100 – benzoylarginine nitroanilide MeSH D12.125.068.050.400 – homoarginine MeSH D12.125.068.050.525 – ng-nitroarginine methyl ester MeSH D12.125.068.050.587 – nitroarginine MeSH D12.125.068.050.650 – omega-n-methylarginine MeSH D12.125.068.050.900 – tosylarginine methyl ester MeSH D12.125.068.060 – asparagine MeSH D12.125.068.330 – glutamine MeSH D12.125.068.330.700 – proglumide MeSH D12.125.068.555 – lysine MeSH D12.125.068.555.478 – hydroxylysine MeSH D12.125.068.555.575 – lysinoalanine MeSH D12.125.068.555.750 – polylysine MeSH D12.125.068.665 – ornithine MeSH D12.125.068.665.340 – eflornithine
Among the Buddhists there was a Tocharian (Tho-gar) king called Men-dre, or Polosi, or Ānandavarmā. He had the caves painted by restorers and painters: Mitradatta; Naravāhanadatta from the lands of the "naked ones" (Niganthas); Priyaratna from Romakam (Byzantine Empire); and other experts in restoration. The king of the Rgya-ser and King Men-dre's bodies were taken by Amitābha and he went to the land of bliss. When the son of the great king of Rgya-ser came to the fort of Mir-li, thanks to the power of prayer, all the "naked ones" (Niganthas) were killed by the followers of Kālacakra, and all of the Buddhist caves were restored. According to Sam van Schaik, "Mendre" could be the Indo-Greek king Menander, or the mythical king Manadhatṛ of Buddhist sources; "Polosi" could be a Chinese abbreviation for king Prasenajit; "Romakam" may be the Byzantine Empire; the "naked ones" would be the Niganthas. In Tibetan, the country named "Tho-gar" "Thod-kar" corresponds to Tokharistan (ancient Bactria).
Sources: en.wikipedia.org
=== Saddiction and hiatus (2024–present) === At the beginning of February 2024, Hangman's Chair returned to perform at Le Mondial du Tatouage – Tattoo Planetarium, which brought together 500 tattoo artists from around the world, at Paris' Grande halle de la Villette. In October 2024, the band released the single "2 am Thoughts" and its music video, taken from the upcoming seventh album, Saddiction. "2 am Thoughts" features a guest appearance from Raven van Dorst of Dool. The music video follows Nackphouminh, the original singer of Hangman's Chair, through a day in his life, three years after he adopted a healthier lifestyle combining sport and spiritual exploration. He is the author of the video's closing line. The band went on a European tour with Dool in October 2024. They released the single "Kowloon Lights" in November. Saddiction was released on 14 February 2025 through Nuclear Blast Records, with the group's lineup remaining unchanged: Chanut, Thépegnier, Hanvic, and Toufouti. A Loner and Saddiction would be part of a new trilogy. The album entered at number 13 on the French SNEP–SCPP Rock and Metal Chart compiled by the OCC. Mathieu David of Rolling Stone France wrote that Hangman's Chair "continues to weave their simultaneously heavy and hovering ambiences amidst mysterious urban landscapes". He added that while A Loner "hovered at 10,000 feet in an ethereal cloud, Saddiction brings back the riffs, not without reminding the harshest ambiences of Banlieue Triste". Other singles followed: "In Disguise", "Healed?", and "The Worst is Yet to Come".
As the strictest of vegetarian diets, a vegan diet excludes all animal products, and can be accompanied by the abstention from animal-derived products, such as leather shoes and silk clothes. Vegetarian diets pose some difficulties. For vitamin B12, depending on the presence or absence of eggs and dairy products in the diet or other reliable B12 sources, vegetarians or vegans may incur a nutritional deficiency. Packaged and processed foods may contain minor quantities of animal ingredients. While some vegetarians scrutinize product labels for such ingredients, others do not object to consuming them, or are unaware of their presence.
=== Industrial === Industrial production of B12 is achieved through fermentation of selected microorganisms. Streptomyces griseus, a bacterium once thought to be a fungus, was the commercial source of vitamin B12 for many years. The species Pseudomonas denitrificans and Propionibacterium freudenreichii subsp. shermanii are more commonly used today. These are grown under special conditions to enhance yield. Rhone-Poulenc improved yield via genetic engineering P. denitrificans. Propionibacterium, the other commonly used bacteria, produce no exotoxins or endotoxins and are generally recognized as safe (have been granted GRAS status) by the Food and Drug Administration of the United States. The total world production of vitamin B12 in 2008 was 35,000 kg (77,000 lb).
== External links == IUPHAR GPCR Database – GHRH receptor Archived 2016-03-03 at the Wayback Machine somatotropin+releasing+hormone+receptor at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
A higher value for pKaH corresponds to a stronger base. For example, the values pKaH (C5H5N) = 5.25 and pKaH ((CH3CH2)3N) = 10.75 indicate that (CH3CH2)3N (triethylamine) is a stronger base than C5H5N (pyridine).
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.
Epitalon is a synthetic tetrapeptide built from four amino acids: alanine, glutamate, aspartate, and glycine. It is not extracted from a natural source but made in the laboratory by chemical synthesis. Its short length makes it relatively straightforward to produce at high purity.