A practical reference on counter-ion: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-06-07. Anything still debated is marked as such rather than presented as settled.
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.
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.
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 |
|---|---|---|
| Peptide sequence | Ala-Glu-Asp-Gly | Single-letter form AEDG |
| Compound class | Synthetic tetrapeptide | Not a natural free peptide |
| Research origin | Russian gerontology institutes | Developed during the 1990s |
| Main research claim | Telomerase activation | Evidence mainly from cultured cells |
| Regulatory status | Not an approved drug | Handled as a research material |
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 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.
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.
The parent extract epithalamin was characterised as a low-molecular-weight fraction of pineal tissue rather than a single defined chemical entity. Researchers fractionated it and tested successive fragments for activity, a screening approach typical of peptide discovery work in that era. Epitalon emerged from that process as one of the shorter sequences of interest. Because the original extract was never fully resolved into individual components, claims about which constituent drives a given effect rest on inference. This distinction matters when reading older reports that attribute extract observations to the tetrapeptide itself.
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.
Documentation accompanying research peptides usually includes a certificate of analysis listing the batch number, purity figure, and test methods applied. Buyers comparing suppliers should check whether the reported purity refers to chromatographic area or to a mass-balance calculation, because the two are not equivalent. Counter-ion content, residual solvents, and water content are sometimes omitted from such certificates even though they affect the actual peptide mass present. Independent verification through a second laboratory is the most direct way to confirm that a supplied material matches its label.
Purity assessment of peptide reagents normally relies on reversed-phase high-performance liquid chromatography. A gradient of acetonitrile in water with trifluoroacetic acid, paired with a C18 stationary phase, separates the target tetrapeptide from truncated sequences and deletion analogues. Detection at 214 nanometres exploits absorbance of the peptide backbone, since the molecule contains no aromatic residue. Results are expressed as a percentage of total peak area. Values above ninety-five percent are typical for research-grade material, although reporting conventions vary between suppliers.
Identity confirmation uses mass spectrometry, usually electrospray ionisation in positive mode or matrix-assisted laser desorption. The protonated free peptide produces a signal near three hundred and ninety-one daltons, while salt adducts shift that value slightly. Tandem mass spectrometry or amino acid analysis supplies sequence-level confirmation, which a single mass measurement cannot. Peptides containing aspartate can cyclise into succinimide intermediates that hydrolyse to isoaspartate isomers of identical mass. Because those isomers are difficult to separate chromatographically, identity and purity results carry more weight when interpreted together.
== Research, teaching and training == As of 2025, the Department of Biochemistry, Cell and Systems Biology is composed of 46 tenured and tenure-track research-focused teaching academics, studying the Departmental research themes of cell biology, systems and computational biology, cell signaling, multiomics, photosynthesis and plants and mechanistic structural biology. The department is home to a broad selection of Early Career Researchers and senior Professorial staff including Sonia Rocha, a specialist in Hypoxia-inducible factor, Dan Rigden, noted for his work with CASP Douglas Kell, a leader in systems and synthetic biology, Claire Eyers, a proteomics and biological mass spectrometry expert, Luning Liu, Ben Goult, J Bernadette Moore, Richard Scheltema, Sylvie Urbe and Roy Goodacre, editor of the peer-reviewed journal Metabolomics (journal). The department possesses dedicated research, mentoring and technical professional support staff, all of whom were recognised through the award of a Gold Athena Swan Award in 2025, one of only a handful of Institutes in the UK to achieve this distinction,. Grant-funded research from across the UKRI, Wellcome, industrial and charity portfolios is performed in state-of-the-art facilities where biochemical approaches sit alongside cutting-edge multiomics technology to study the chemistry of life.
In the 2000s, some chocolate producers began to engage in fair trade initiatives, to address concerns about the low pay of cocoa laborers in developing countries. Traditionally, Africa and other developing countries received low prices for their exported commodities such as cocoa, which caused poverty. Fairtrade seeks to establish a system of direct trade from developing countries to counteract this system. One solution for fair labor practices is for farmers to become part of an agricultural cooperative. Cooperatives pay farmers a fair price for their cocoa so farmers have enough money for food, clothes, and school fees. One of the main tenets of fair trade is that farmers receive a fair price, but this does not mean that the larger amount of money paid for fair trade cocoa goes directly to the farmers. The effectiveness of fair trade has been questioned. In a 2014 article, The Economist stated that workers on fair trade farms have a lower standard of living than on similar farms outside the fair trade system based on a study of tea and coffee farmers in Uganda and Ethiopia.
The dominions and colonies provided 57 contingents, overwhelmingly of volunteer forces as none had a substantial full-time force; those from Canada alone numbered some 7,400 Altogether, Britain and her empire deployed some half a million soldiers. After the South African War, the Conservative government embarked on a series of reorganisations that had a negative impact on all the auxiliary forces. The Militia was heavily understrength and disorganised, whilst the number of recruits for the Volunteers was falling off and it was becoming apparent that many Volunteer Corps were headed towards financial collapse unless some action was taken. The Territorial Force was created by the Secretary of State for War, Richard Burdon Haldane, following the enactment of the Territorial and Reserve Forces Act 1907 which combined and re-organised the old Volunteer Force with the Yeomanry. As part of the same process, the remaining units of militia were converted to the Special Reserve. Most Volunteer infantry units had unique identities, but lost these in the reorganisation, becoming Territorial battalions of Regular Army infantry regiments. Only one infantry unit, the London Regiment, has maintained a separate identity. The TF was formed on 1 April 1908 and contained fourteen infantry divisions, and fourteen mounted yeomanry brigades. It had an overall strength of approximately 269,000. Haldane designed it to provide a much larger second line for the six divisions of the Expeditionary Force which he was establishing as the centerpiece of the Regular Army.
Several methods are proposed for using quantum dots to improve existing light-emitting diode (LED) design, including quantum dot light-emitting diode (QD-LED or QLED) displays, and quantum dot white-light-emitting diode (QD-WLED) displays. Because quantum dots naturally produce monochromatic light, they can be more efficient than light sources which must be color filtered. QD-LEDs can be fabricated on a silicon substrate, which allows them to be integrated onto standard silicon-based integrated circuits or microelectromechanical systems.
Sources: en.wikipedia.org
=== Right lung === The right lung has both more lobes and segments than the left. It is divided into three lobes, an upper, middle, and a lower lobe by two fissures, one oblique and one horizontal. The upper, horizontal fissure, separates the upper from the middle lobe. It begins in the lower oblique fissure near the posterior border of the lung, and, running horizontally forward, cuts the anterior border on a level with the sternal end of the fourth costal cartilage; on the mediastinal surface it may be traced back to the hilum. The lower, oblique fissure, separates the lower from the middle and upper lobes and is closely aligned with the oblique fissure in the left lung. The mediastinal surface of the right lung is indented by a number of nearby structures. The heart sits in an impression called the cardiac impression. Above the hilum of the lung is an arched groove for the azygos vein, and above this is a wide groove for the superior vena cava and right brachiocephalic vein; behind this, and close to the top of the lung is a groove for the brachiocephalic artery. There is a groove for the oesophagus behind the hilum and the pulmonary ligament, and near the lower part of the oesophageal groove is a deeper groove for the inferior vena cava before it enters the heart. The weight of the right lung varies between individuals, with a standard reference range in men of 155–720 g (0.342–1.587 lb) and in women of 100–590 g (0.22–1.30 lb).
A chemical reaction is a transformation of some substances into one or more different substances. The basis of such a chemical transformation is the rearrangement of electrons in the chemical bonds between atoms. It can be symbolically depicted through a chemical equation, which usually involves atoms as subjects. The number of atoms on the left and the right in the equation for a chemical transformation is equal. (When the number of atoms on either side is unequal, the transformation is referred to as a nuclear reaction or radioactive decay.) The type of chemical reactions a substance may undergo and the energy changes that may accompany it are constrained by certain basic rules, known as chemical laws. Energy and entropy considerations are invariably important in almost all chemical studies. Chemical substances are classified in terms of their structure, phase, as well as their chemical compositions. They can be analyzed using the tools of chemical analysis, e.g. spectroscopy and chromatography. Scientists engaged in chemical research are known as chemists. Most chemists specialize in one or more sub-disciplines. Several concepts are essential for the study of chemistry; some of them are:
In a broad academic audience, the concept of the evolution of the genetic code from its original ambiguous form to a well-defined ("frozen") code with the repertoire of 20 (+2) canonical amino acids is widely accepted. However, there are different opinions, concepts, approaches and ideas regarding how to best reproduce this process experimentally. Even models are proposed that predict "entry points" for synthetic amino acid invasion of the genetic code. Since 2001, 40 non-natural amino acids have been added into proteins by creating a unique codon (recoding) and a corresponding transfer-RNA:aminoacyl – tRNA-synthetase pair to encode it with diverse physicochemical and biological properties in order to be used as a tool to exploring protein structure and function or to create novel or enhanced proteins. H. Murakami and M. Sisido extended some codons to have four and five bases. Steven A. Benner constructed a functional 65th (in vivo) codon. In 2015 N. Budisa, D. Söll and co-workers reported the full substitution of all 20,899 tryptophan residues (UGG codons) with unnatural thienopyrrole-alanine in the genetic code of the bacterium E. coli. In 2016 the first stable semisynthetic organism was created. It was a (single cell) bacterium with two synthetic bases (called X and Y). The bases survived cell division. In 2017, researchers in South Korea reported that they had engineered a mouse with an extended genetic code that can produce proteins with unnatural amino acids. In May 2019, researchers reported the creation of a new "Syn61" strain of the E. coli bacteria.
Sources: en.wikipedia.org
Vladimir Khavinson and colleagues at research institutes in Saint Petersburg developed and studied the peptide. Their program examined short peptides as regulators of aging and neuroendocrine function. Epitalon was one of several compounds produced by that group.
That question is not settled. Cell culture studies have reported increased telomerase activity after treatment, but comparable evidence from controlled human trials is lacking. Any claim about telomere lengthening in people should be treated as unproven.
It has not completed the large, controlled trials required for drug approval in major jurisdictions. Most human reports involve small samples and limited follow-up. As a result, it is sold as a research chemical rather than a licensed pharmaceutical product.
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.