tetrapeptide 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 2025-11-03. Where a claim depends on a specific study, the study is described rather than over-claimed.
The molecule is a short, linear, hydrophilic peptide that dissolves readily in water or aqueous buffer. Its principal chemical liabilities are hydrolytic rather than oxidative, since it contains no cysteine, methionine, or tryptophan residues. The aspartate–glycine step is a recognised site for aspartimide formation under mildly acidic or basic conditions, generating isoaspartate and succinimide-related products over time. Desiccated lyophilised powder held at −20 °C is comparatively stable, whereas dilute solutions degrade faster and are best frozen as single-use aliquots rather than thawed repeatedly.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Identity confirmation | Electrospray or MALDI mass spectrometry | Observed mass compared with theoretical 390.35 Da |
| Purity specification | 95 percent or greater by RP-HPLC | Common convention for research-grade peptide |
| Counter-ion | Acetate or trifluoroacetate | Affects net peptide content of a weighed sample |
| Solution storage | −80 °C as single-use aliquots | Repeated freeze–thaw cycles accelerate loss |
| Main degradation route | Aspartimide formation at Asp-Gly | Produces isoaspartate and related species |
The most widely cited claim is that epitalon activates telomerase and thereby extends telomere length. Supporting evidence comes largely from cultured human cells, where treatment was associated with increased telomerase activity and delayed replicative senescence. Telomerase activation is a biologically consequential effect, since the enzyme is largely silenced in most somatic cells. However, the route by which a short peptide would reach and act on the enzyme's regulatory machinery has not been established. Independent replication in human trials is scarce, so the link between cell-culture observations and whole-body aging remains an open question.
Human data are limited to small studies, often without the randomization, blinding, or control groups expected in contemporary clinical research. Reported outcomes have included changes in melatonin levels, immune markers, and subjective measures, but sample sizes were generally too small to support firm conclusions. Some reviews treat the peptide as promising while noting methodological weaknesses; others question whether the observed effects are specific. The compound is frequently discussed in longevity-focused communities, where enthusiasm often outpaces the published evidence. Separating established findings from speculation is therefore important when reading summaries of this research.
Epitalon emerged from research conducted in Saint Petersburg by Vladimir Khavinson and colleagues, who studied short peptides as potential regulators of aging. The work built on epithalamin, a pineal gland extract reported to influence neuroendocrine function. Epitalon was designed as a synthetic counterpart with a defined sequence, allowing reproducible experiments that extracts could not support. Early publications described effects on melatonin rhythms and lifespan in animal models. These findings circulated mainly in Russian-language journals during the 1990s, which limited their visibility among English-speaking researchers.
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.
Laboratory-grade epitalon is typically supplied as a lyophilized powder. Purity is commonly assessed with reverse-phase high-performance liquid chromatography, often paired with mass spectrometry to confirm molecular identity. Amino acid analysis and peptide mapping can provide additional confirmation of sequence. Certificates of analysis for research materials frequently report purity above 95 percent, although the methods behind such figures vary between suppliers. The absence of a pharmacopeial monograph means that no single standardized assay defines the compound, so reported results depend on the analytical protocol chosen.
=== Li–Lu === Andreas Libavius (1555–1616), German doctor and alchemist who discovered how prepare hydrochloric acid, ammonium sulfate, etc. Carl Theodore Liebermann (1842–1914), German chemist, known for synthesis of alizarin Willard Libby (1908–1980), American chemist known for development of radiocarbon dating, 1960 Nobel Prize in Chemistry Justus von Liebig (1803–1873), German inventor and pioneer in agricultural and biological chemistry Karl Paul Link (1901–1978), American biochemist, discovered the anticoagulant warfarin John Wilfrid Linnett (1913–1975), British chemist at the Universities of Oxford and Cambridge, known for contributions to theoretical chemistry William Lipscomb (1919–2011), American chemist known for work in nuclear magnetic resonance, theoretical chemistry, boron chemistry, and biochemistry; 1976 Nobel Prize in Chemistry Joseph Lister, 1st Baron Lister (1827–1912), English surgeon known for recognising that putrefaction in wounds is caused by germs Arthur H. Livermore (1915–2009), American science educator and chemist who contributed to the synthesis of penicillin Mikhail Lomonosov (1711–1765), Russian scientist, anticipated the kinetic-molecular theory by 100 years H.
== Principle == Delayed neutrons are associated with the beta decay of the fission products. After prompt fission neutron emission the residual fragments are still neutron rich and undergo a beta decay chain. The more neutron rich the fragment, the more energetic and faster the beta decay. In some cases the available energy in the beta decay is high enough to leave the residual nucleus in such a highly excited state that neutron emission instead of gamma emission occurs. Using U-235 as an example, this nucleus absorbs thermal neutrons, and the immediate mass products of a fission event are two large fission fragments, which are remnants of the formed U-236 nucleus. These fragments emit two to three free neutrons (2.43 on average), called "prompt" neutrons. A subsequent fission fragment occasionally undergoes a stage of radioactive decay (which is a beta minus decay) that yields a new nucleus (the emitter nucleus) in an excited state that emits an additional neutron, called a "delayed" neutron, to get to ground state. These neutron-emitting fission fragments are called delayed neutron precursor atoms. The longest-lived groups can be traced to specific decay chains. In about 70% of 87Br beta decays (half-life 55 s), the 87Kr daughter is left in a nuclear state above the 5.4 MeV needed to eject its last neutron; it promptly releases a neutron, ending as stable 86Kr. The neutron emission rate is set by the rate of formation of 87Kr, so the group carries the 55 s half-life of the precursor.
== Medical uses == Buserelin is approved for the treatment of hormone-responsive cancers including prostate cancer and premenopausal breast cancer, sex hormone-dependent uterine diseases including endometrial hyperplasia, endometriosis, and uterine fibroids, and in assisted reproduction for female infertility. It is also used off-label for the treatment of precocious puberty, as a puberty blocker in transgender children, and as a component of transgender hormone therapy. In ovulation induction, buserelin is used for pituitary suppression as an adjunct to gonadotropin administration. It has also been assessed as a nasal spray for use as a hormonal contraceptive in women, with a 96% anovulation rate.
Sources: en.wikipedia.org
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In 1972, Hughes sold the tool division of Hughes Tool Company, and reconsolidated his remaining holdings as the Summa Corporation, which included Hughes' property and other businesses. The Aircraft Division became the Hughes Helicopter Division, Summa Corp. That same year, the US Army issued a request for proposals (RFP) for an Advanced Attack Helicopter (AAH). From an initial list of 5 manufacturers Hughes Aircraft's Toolco Aircraft Division (later Hughes Helicopters) and Bell were selected as finalists. In 1975, Hughes' Model 77/YAH-64 was selected over Bell's YAH-63. First flight of a development prototype occurred in 1977. Also in 1975, Hughes engineers at began concept development work of NOTAR. In 1981, Summa's Hughes Helicopter Division was reconstituted as Hughes Helicopters, Inc.. By December, six AH-64A prototypes had been built and the Army had awarded a purchase contract to the company. Production would reach more than 1,100 by 2005. In 1983, the first production model AH-64 rolled off the production line at the company's new Mesa, Arizona facility. That same year, the company was honored by the National Aeronautic Association with the prestigious Collier Trophy. The company also licensed Schweizer Aircraft to produce the Model 300C. In January 1984, Hughes Helicopters, Inc. was sold to McDonnell Douglas by Summa Corporation, under the parent's efforts to streamline its focus and interest in real estate development. McDonnell Douglas paid $470 million for the company and made it a subsidiary.
Lipofuscin is the name given to fine yellow-brown pigment granules composed of lipid-containing residues of lysosomal digestion. It is considered to be one of the aging or "wear-and-tear" pigments, found in the liver, kidney, heart muscle, retina, adrenals, nerve cells, and ganglion cells.
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Sources: en.wikipedia.org
Mass spectrometry provides the identity check, because the observed mass is compared with the theoretical mass of the AEDG sequence. Chromatography separates and quantifies impurities but does not by itself prove which peptide is present. The two techniques are normally used together.
Yes. Trifluoroacetate and acetate ions remain associated with the peptide after purification, so a weighed quantity of powder contains less peptide than the nominal mass suggests. Certificates that report net peptide content rather than raw weight are more directly comparable between suppliers.
Dilute aqueous solutions are less stable than the dry powder and are usually aliquoted and frozen to avoid repeated freeze–thaw cycles. Lyophilised material is best stored desiccated at −20 °C, protected from light. Working solutions are typically prepared fresh from a frozen aliquot.
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.