This is a working overview of telomerase, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2025-12-01 and is reviewed periodically as new material appears.
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.
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.
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.
Chemically, the molecule consists of four amino acid residues joined by three peptide bonds, with a free N-terminal amino group and a free C-terminal carboxyl group. Its molecular formula is C14H22N4O9, and its monoisotopic mass is approximately 390 daltons. The acidic glutamate and aspartate side chains give the peptide a net negative charge near neutral pH, a property that shapes its chromatographic behaviour and solubility profile. No disulfide bridges or other post-translational modifications are present, so the primary sequence alone defines the structure.
Most experimental work has been carried out in cell culture and animal models. Several reports describe changes in telomerase activity and proliferation in cultured cells, while rodent studies have examined lifespan, melatonin rhythm and reproductive endpoints. Human data remain limited, and much of the published clinical material consists of small trials with incomplete reporting of methods and controls. Whether the cell and animal findings translate into measurable effects in people is an open question, and the mechanistic basis of the reported telomerase changes is not fully established.
== See also == Constant-weight code – Method for encoding data in communications, where a constant number of bits are set Two-out-of-five code – Error-detection code for decimal digits, widely used in barcoding and at one time in telephone exchanges Bi-quinary coded decimal – Numeral encoding scheme Gray code – Ordering of binary values, used for positioning and error correction Kronecker delta – Mathematical function of two variables; outputs 1 if they are equal, 0 otherwise Indicator vector Serial decimal Single-entry vector – Concept in mathematicsPages displaying short descriptions of redirect targets Unary numeral system – Base-1 numeral system Uniqueness quantification – Logical quantifier XOR gate – Logic gate
Normally in humans only one follicle becomes dominant and survives to grow to 18–30 mm in size and ovulate, the remaining follicles in the cohort undergo atresia. The sharp increase in estradiol production by the dominant follicle (possibly along with a decrease in gonadotrophin surge-attenuating factor) cause a positive effect on the hypothalamus and pituitary and rapid GnRH pulses occur and an LH surge results. The increase in serum estradiol levels causes a decrease in FSH production by inhibiting GnRH production in the hypothalamus. The decrease in serum FSH level causes the smaller follicles in the current cohort to undergo atresia as they lack sufficient sensitivity to FSH to survive. Occasionally two follicles reach the 10 mm stage at the same time by chance and as both are equally sensitive to FSH both survive and grow in the low FSH environment and thus two ovulations can occur in one cycle possibly leading to non-identical (dizygotic) twins.
=== Enlarged prostate === Flutamide has been studied in the treatment of benign prostatic hyperplasia (BPH; enlarged prostate) in men in several clinical studies. It has been found to reduce prostate volume by about 25%, which is comparable to the reduction achieved with the 5α-reductase inhibitor finasteride. Unfortunately, it has been associated with side effects in these studies including gynecomastia and breast tenderness (in about 50% of patients), gastrointestinal disturbances such as nausea, diarrhea, and flatulence, and hepatotoxicity, although sexual function including libido and erectile potency were maintained.
In the case of bleeding on probing, which is a diagnostic tool for dentists to routinely check the condition of the gums, the periodontal probe, when inserted gently into the gingival sulcus, is used to measure the depth of the periodontal pocket but upon contact with the sulcular epithelium, should not cause bleeding in individuals with good gingival health. This is due to the resiliency of the sulcular epithelium that has a healthy thickness with a strong underlying collagen architecture. Sites with greater inflammation tend to have more cells yet possess a weaker collagen architecture, making bleeding on probing more noticeable, which is a common finding in stage 2 (early) gingivitis. This highlights the importance of the sulcular epithelium as a physical barrier to protect the underlying connective tissue. When its surface is ulcerated and discontinuous, it allows bacteria to enter more easily. In fact, the total area where bacteria can come in contact with the affected gum tissue is estimated to be as large as the palm of an adult’s hand. Once in the established lesion stage of gingivitis, collagen depletion continues as more polymorphonuclear (PMN) cells seep into the gingival sulcus and infiltrate the spaces within the sulcular epithelium. Permeability of the gingival sulcus (sulcular epithelium & junctional epithelium) also increases with the progress of gingival inflammation.
Sources: en.wikipedia.org
When a semen analysis does indicate abnormal results, lifestyle factors recommendations prior to a new semen sample include a nutritional diet, as well as limitations on smoking and alcohol use. A cold bath and removal of tight-fitted underwear apparel may also be recommended within the month prior to re-examination.
Hundreds of additional cases of liver complications in people taking bicalutamide exist in the FDA Adverse Event Reporting System (FAERS) database. In all of the published case reports of liver toxicity with bicalutamide, the onset of symptoms was within the first 6 months of treatment. Symptoms that may indicate liver dysfunction include nausea, vomiting, abdominal pain, fatigue, anorexia, "flu-like" symptoms, dark urine, and jaundice. There are also published case reports of interstitial pneumonitis and eosinophilic lung disease associated with bicalutamide. along with hundreds of additional instances in the FAERS database as well. Interstitial pneumonitis can potentially progress to pulmonary fibrosis and may be fatal. Symptoms that may indicate lung dysfunction include dyspnea (difficult breathing or shortness of breath), cough, and pharyngitis (inflammation of the pharynx, resulting in sore throat). The exact incidence of liver toxicity and interstitial pneumonitis with bicalutamide are unknown, but both are said to be very rare events. A few cases of photosensitivity have been reported with bicalutamide. Hypersensitivity reactions (drug allergy) like angioedema and hives have also uncommonly been reported in association with bicalutamide. Because it is an antiandrogen, bicalutamide has a theoretical risk of birth defects like ambiguous genitalia in male fetuses. Due to its teratogenic capacity, contraception should be used in women taking bicalutamide who are fertile and sexually active.
In this experiment it was shown that the overall DFE is bimodal, with a cluster of neutral mutations, and a broad distribution of deleterious mutations. Though relatively few mutations are advantageous, those that are play an important role in evolutionary changes. Like neutral mutations, weakly selected advantageous mutations can be lost due to random genetic drift, but strongly selected advantageous mutations are more likely to be fixed. Knowing the DFE of advantageous mutations may lead to increased ability to predict the evolutionary dynamics. Theoretical work on the DFE for advantageous mutations has been done by John H. Gillespie and H. Allen Orr. They proposed that the distribution for advantageous mutations should be exponential under a wide range of conditions, which, in general, has been supported by experimental studies, at least for strongly selected advantageous mutations. In general, it is accepted that the majority of mutations are neutral or deleterious, with advantageous mutations being rare; however, the proportion of types of mutations varies between species. This indicates two important points: first, the proportion of effectively neutral mutations is likely to vary between species, resulting from dependence on effective population size; second, the average effect of deleterious mutations varies dramatically between species. In addition, the DFE also differs between coding regions and noncoding regions, with the DFE of noncoding DNA containing more weakly selected mutations.
Sources: en.wikipedia.org
== Management == Treatment usually involves antimicrobial mouth washes and oral antibiotics to help the immune system fight the attendant infection, and it also often involves local surgery(resection) to get rid of the dead bone (necrotic bone lesion). Many patients with MRONJ have successful outcomes after treatment, meaning that the local osteonecrosis is stopped, the infection is cleared, and the mucosa heals and once again covers the bone. The treatment the person receives depends on the severity of osteonecrosis of the jaw.
=== Preservation === Examples of many styles of refrigerators and ice cars can be found at railroad museums around the world. The Western Pacific Railroad Museum at Portola, California features a very complete roster of 20th-century cars, including wood-bodied ice cars, steel-bodied ice cars, one of the earliest mechanical refrigerator cars, later mechanical refrigerator cars, and a cryogenic reefer, as well as several "insulated" boxcars also used for food transport.
Dent, London, 1981) ISBN 978-0-460-04535-3 Is Life an Astronomical Phenomenon? (University College Cardiff Press, 1982) ISBN 9780906449493 Why Neo-Darwinism Does Not Work (with Fred Hoyle) (University College Cardiff Press, 1982) ISBN 9780906449509 Proofs that Life is Cosmic (with Fred Hoyle) (Institute of Fundamental Studies, Sri Lanka, Memoirs no.1, 1982) From Grains to Bacteria (with Fred Hoyle) (University College Cardiff Press, 1984) ISBN 9780906449646 Fundamental Studies and the Future of Science (ed.) (University College Cardiff Press, 1984) ISBN 9780906449578 Living Comets (with Fred Hoyle) (University College Cardiff Press, 1985) ISBN 9780906449790 Archaeopteryx, the Primordial Bird: A Case of Fossil Forgery (with Fred Hoyle) (Christopher Davies, Swansea, 1986) ISBN 9780715406656 The Theory of Cosmic Grains (with Fred Hoyle) (Kluwer, Dordrecht, 1991) ISBN 9780792311898 Life on Mars? The Case for a Cosmic Heritage (with Fred Hoyle) (Clinical Press, Bristol, 1997) ISBN 9781854570413 Astronomical Origins of Life: Steps towards Panspermia (with Fred Hoyle) (Kluwer, Dordrecht, 2000) ISBN 9780792360810 Cosmic Dragons: Life and Death on Our Planet (Souvenir Press, London, 2001) ISBN 9780285636064 Fred Hoyle's Universe (ed. with G. Burbidge and J. Narlikar) (Kluwer, Dordrecht, 2003) ISBN 9781402014154 A Journey with Fred Hoyle (World Scientific, Singapore, 2005) ISBN 9789812565792 Comets and the Origin of Life (with J. Wickramasinghe and W.
=== Mislabelled door swipe data === During the first trial, door swipe records were used to establish Letby's presence on the neonatal unit at the time of various incidents. In August 2024, the Crown Prosecution Service confirmed that swipe data for one of the unit's doors had been mislabelled, with entries and exits reversed. The CPS did not confirm whether data for other doors had been correctly labelled. Cheshire Police reviewed the use of the incorrect data and concluded that it had been relied upon in evidence relating to nine infants, although it played a central role only in the case of Child K, for whom Letby was not convicted at the first trial. A second door to the unit did not record entries or exits, meaning that swipe card data could not account for all movements into and out of the unit.
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.