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 2025-08-05 and is reviewed periodically as new material appears.
Storage and handling follow conventional peptide practice. Lyophilized epitalon is typically kept refrigerated or frozen, protected from moisture and light, and allowed to equilibrate to room temperature before opening to avoid condensation. Once dissolved, aqueous solutions are usually stored cold and used within a short period, since dilute peptide solutions can support microbial growth and may slowly degrade. The absence of cysteine and methionine reduces, but does not eliminate, oxidation concerns during long-term storage.
Regulatory status varies by country and is not harmonized. Epitalon is not an approved drug in major Western jurisdictions. In some countries it is sold as a research chemical, and in others it has appeared in products marketed for other categories. This inconsistent status means that purity, labeling accuracy, and documentation differ widely between suppliers, and verification of identity and purity through independent analysis is the usual way buyers assess a given lot.
Epitalon appears in the literature primarily through a small number of research groups, most of them associated with the St. Petersburg Institute of Bioregulation and Gerontology. Publications describe cell culture experiments, animal studies, and a limited number of small human studies. Independent replication outside this network is sparse. As a result, reviews of the topic usually separate descriptive reports of observed effects from the question of whether those effects generalize, and they note the difficulty of comparing studies that use different preparations and endpoints.
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.
Storage practice centres on limiting moisture, oxygen, and repeated temperature cycling. Freeze-dried powder is generally held desiccated at minus twenty degrees Celsius or colder and protected from light. Reconstituted solutions are markedly less stable, and the aspartate-glycine junction is prone to succinimide formation at neutral to mildly alkaline pH. Portioning material into single-use aliquots reduces degradation compared with repeated freeze-thaw cycles. Stability data specific to this tetrapeptide remain scarce, so most handling guidance is extrapolated from general peptide chemistry rather than measured directly.
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.
| Property | Value | Notes |
|---|---|---|
| Purity assessment | RP-HPLC | Reported as percent area, often ≥95% |
| Identity confirmation | Mass spectrometry | Observed mass compared with ~390 Da |
| Typical storage temperature | -20 °C or below | Lyophilized powder, desiccated |
| Reconstitution solvent | Sterile water or buffer | Acidic residues aid dissolution |
| Common synonyms | AEDG; epithalon | Spelling varies in literature |
Laboratory handling begins with dissolution of the lyophilized powder in water or a suitable aqueous buffer. The dry solid is the more stable form, so stock solutions are generally prepared only when required and kept cold afterwards. Repeated freezing and thawing of a solution is avoided because it encourages aggregation and gradual loss of the intact chain. Diluents and containers are selected to limit adsorption of a short peptide onto plastic surfaces and to reduce microbial growth in aqueous preparations.
Stability depends strongly on pH, temperature and the presence of oxygen and trace metals. Cleavage of the backbone proceeds faster under neutral to alkaline conditions, whereas acidic solutions tend to slow that reaction. The aspartate and glutamate side chains can undergo deamidation or imide formation over time, generating closely related impurities. Published stability data specific to epitalon are sparse, so the usable life of a given solution is best regarded as an open question that depends on buffer composition, concentration and storage temperature.
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.
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.
No national medicines regulator has approved epitalon as a therapeutic product. It is generally distributed as a research chemical, and in some jurisdictions selling peptides for human consumption without approval is restricted or prohibited. Certificates of analysis accompanying commercial material vary in which tests are performed, and independent verification of identity and purity is uncommon. Statements about anti-ageing or disease-prevention benefits on vendor pages are marketing claims rather than regulatory findings, a distinction that shapes how the compound is discussed in scientific and popular sources alike.
The most frequently cited laboratory finding is that AEDG increased telomerase activity and extended telomere length in cultured human somatic cells. That work used fetal fibroblast strains and reported changes in enzyme activity alongside altered division counts. Replication by unrelated groups has been limited, and the published record is largely a single-laboratory series rather than a multi-centre programme. The result supports a hypothesis about peptide influence on gene expression in cell culture; it does not by itself establish an effect on telomere length in living animals or in people.
Animal and clinical reports appear mainly in Russian-language journals from the 1990s and 2000s, covering endpoints such as melatonin rhythm, lifespan in aged rodents, and retinal function. Many of these papers involve small groups, lack blinding or placebo comparison, and are difficult to retrieve through indexed databases. Review articles published in English generally summarise the claims without reanalysing the underlying data. Because no large randomised trial exists, the clinical importance of these reported effects stays unresolved and is properly described as an open question.
== Styrene derivatives == This group contains a benzene and also an ethylene group, being derived from styrene. Coniferin (C16H22O8) occurs in the cambium of conifer wood. Emulsin converts it into glucose and coniferyl alcohol. Oxidation of coniferin gives glucovanillin, which yields upon treatment with emulsin glucose and vanillin. Syringin, which occurs in the bark of Syringa vulgaris, is a methoxyconiferin. Phloridzin occurs in the root-bark of various fruit trees; it hydrolyses to glucose and phloretin, which is the phloroglucin ester of paraoxyhydratropic acid. It is related to the pentosides naringin (C27H32O14), which hydrolyzes to rhamnose and naringenin, the phloroglucin ester of p-coumaric acid, and hesperidin, which hydrolyzes to rhamnose and hesperetin, the phloroglucin ester of isoferulic acid (C10H10O4).
=== 2002 === 20 July How to Live Forever, an Equinox Special, and update in October 1999's Curing the Incurable; the Center for Strategic and International Studies (CSIS), and possible huge demographic realignments facing Europe, with influx of citizens from less-wealthy continents, as well as a likely pensions crisis; Osiris Therapeutics; apoptosis and Ian Judson, and trials of imatinib for gastrointestinal stromal tumors (GIST); the Geron Corporation and the Hayflick limit; Human Genome Sciences of Rockville, Maryland, and regenerative medicine; Vandana Shiva of India; Sir Ian Wilmut of the Roslin Institute in Edinburgh. Produced by David Paterson, directed by David Malone, made by Boa 2001
== Specialties == Proline is one of the two amino acids that do not follow along with the typical Ramachandran plot, along with glycine. Due to the ring formation connected to the beta carbon, the ψ and φ angles about the peptide bond have fewer allowable degrees of rotation. As a result, it is often found in "turns" of proteins as its free entropy (ΔS) is not as comparatively large to other amino acids and thus in a folded form vs. unfolded form, the change in entropy is smaller. Furthermore, proline is rarely found in α and β structures as it would reduce the stability of such structures, because its side chain α-nitrogen can only form one nitrogen bond. Additionally, proline is the only amino acid that does not form a red-purple colour when developed by spraying with ninhydrin for uses in chromatography. Proline, instead, produces an orange-yellow colour.
British scientists also used unconventional methods for sourcing possible bomb debris: workers holidaying in Europe were instructed to collect pinecones, and crates of tea leaves were imported from China.
Sources: en.wikipedia.org
=== Mask squeeze === If a diver's mask is not equalized during descent the relative negative internal pressure can produce petechial hemorrhages in the area covered by the mask along with subconjunctival hemorrhages.
=== Period 1: Initial transitional style === The first period consist in a short interval of transitional style, in which paintings remain subtil and rather nuanced, but blue pigments have started to appear. The Cave of the Devil C (Cave 198) and Cave of the Devil A (Cave 199), as well as the Cave with the Steps (Cave 110) and sometimes the Red-domed Cave A (Cave 67) are considered as the first period of this new style.
== Critical reception == Gordon Freeman quickly became and then remained one of the most popular video game characters ever. In 2008, The Age ranked him as the 16th-best Xbox character of all time, adding that "no one has done more for the reputations and street cred of theoretical physicists than Valve." In 2009, GameDaily listed the "strong and silent type" in their top 25 video game archetypes, using Gordon Freeman as an example. In 2010, Empire ranked him as the number one Greatest Video Game Character, commenting that "the character is the quintessential geek fantasy" who "has become a gaming icon, synonymous with the apotheosis of first-person action." He was also ranked 14th on UGO.com's list of top 100 heroes in all media, with a comment that "an MIT graduate, donning black-framed glasses and a goatee, he's not the guy you'd picture decimating the alien threat." In 2012, GamesRadar ranked him as the sixth "most memorable, influential, and badass" protagonist in games, adding: "It's how the characters of the Half-Life universe treat Gordon Freeman, not the way he treats them, that shape such a compelling character." In 2013, Complex ranked him as the 45th "most badass" video game character of all time. In 1998, readers of GameSpot ranked him as the fifth-best Hero of gaming. In 2009, a public poll on GameSpot resulted in him being voted the All Time Greatest Video Game Hero. He was also voted as the eighth-best video game character of all time in the Guinness World Records Gamer's Edition 2011.
Sources: en.wikipedia.org
=== Fragrance === The great majority of tulips, both species and cultivars, have no discernable scent, but a few of both are scented to a degree, and Anna Pavord describes T. hungarica as "strongly scented", and among cultivars, some such as "Monte Carlo" and "Brown Sugar" are "scented", and "Creme Upstar" "fragrant".
==== Sex differences ==== In humans, oxytocin differentially affects males and females. Females who are administered oxytocin are overall faster in responding to socially relevant stimuli than males who receive oxytocin. Additionally, after the administration of oxytocin, females show increased amygdala activity in response to threatening scenes; however, males do not show increased amygdala activation. This phenomenon can be explained by examining the role of gonadal hormones, specifically estrogen, which modulate the enhanced threat processing seen in females. Estrogen has been shown to stimulate oxytocin release from the hypothalamus and promote receptor binding in the amygdala. It has also been shown that testosterone directly suppresses oxytocin in mice. This has been hypothesized to have evolutionary significance. With oxytocin suppressed, activities such as hunting and attacking invaders would be less mentally difficult as oxytocin is strongly associated with empathy.
=== Substrate specificity === Under normal circumstances, caspases recognize tetra-peptide sequences on their substrates and hydrolyze peptide bonds after aspartic acid residues. Caspase 3 and caspase 7 share similar substrate specificity by recognizing tetra-peptide motif Asp-x-x-Asp. The C-terminal Asp is absolutely required while variations at other three positions can be tolerated. Caspase substrate specificity has been widely used in caspase based inhibitor and drug design.
Sources: en.wikipedia.org
Identity is normally confirmed by mass spectrometry, which checks the measured mass against the expected value near 390 daltons. Reverse-phase high-performance liquid chromatography is used alongside it to assess purity. Amino acid analysis can provide additional composition data.
The powder is generally kept refrigerated or frozen, protected from light and moisture. Vials should reach room temperature before opening to prevent condensation. Reconstituted solutions are usually stored cold and used within a limited window because dilute solutions can degrade or support microbial growth.
Epitalon is not an approved drug in major Western regulatory jurisdictions. Its legal status differs between countries, and it is often distributed as a research chemical. This means product documentation and purity vary considerably between suppliers.
Reversed-phase high-performance liquid chromatography with ultraviolet detection at 214 nanometres is the usual approach. Peak area percentage provides a purity figure relative to other components in the sample. Mass spectrometry is then applied to confirm identity.