Khavinson 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.
Last reviewed on 2026-04-20. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Identity and purity are checked by reversed-phase high-performance liquid chromatography, usually with ultraviolet detection near 214 nanometres, where the peptide bond absorbs. Mass spectrometry confirms the expected mass and reveals whether truncation products or adducts are present. Acid hydrolysis followed by amino acid analysis gives the residue ratio, which should approximate one alanine, one glutamate, one aspartate and one glycine. Counter-ions such as acetate or trifluoroacetate remain in the dried product and lower net peptide content, so a stated purity figure on a label does not by itself describe how much peptide a vial holds.
Regulatory treatment differs by country. No formulation of epitalon holds a marketing authorisation as a medicine in the United States or the European Union, where material sold for laboratory use is handled as a research chemical and is not intended for human consumption. In Russia, several short peptide preparations from the same institute's peptide series are registered medicinal products, and epitalon appears in that national context. Elsewhere it is frequently offered as a cosmetic ingredient, a category with lighter requirements. Advertising claims about longevity or disease prevention are restricted in most jurisdictions, which limits how sellers describe the compound.
Freeze-dried epitalon is normally kept at minus twenty degrees Celsius in a sealed, desiccated container, protected from light. Short excursions at ambient temperature during shipping are generally tolerated, but repeated warming and cooling cycles encourage moisture uptake, which shortens shelf life. Once dissolved, the peptide is far less stable than the solid: aqueous solutions are subject to hydrolysis and to deamidation at the aspartate and glutamate residues. Working solutions are therefore held refrigerated and used within days, and repeated freezing and thawing of the same vial is best avoided.
| 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 |
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.
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.
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.
Analytical characterization of epitalon relies on standard peptide methods. Reverse-phase high-performance liquid chromatography is used to assess purity, and mass spectrometry confirms identity by checking the observed mass against the expected value near 390 daltons. Amino acid analysis can verify composition. Because the peptide is short and hydrophilic, it elutes early on many reverse-phase columns, so method development often requires ion-pairing reagents to achieve adequate retention and resolution from related impurities.
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.
Because epitalon has no pharmacopoeial monograph, quality assessment depends on supplier documentation and independent testing. Certificates of analysis typically report a purity figure from a single chromatographic run, a measured mass and sometimes an appearance description, but methods and acceptance criteria are not harmonised across vendors. Third-party laboratories can repeat identity and purity measurements, and mismatches between labelled and measured peptide content have been described for research peptides generally. What constitutes adequate identity confirmation for a molecule of this size stays an open question, since mass agreement alone does not separate closely related sequences.
Identity testing for epitalon relies on reversed-phase high-performance liquid chromatography for purity and mass spectrometry for mass confirmation. Because the sequence contains no tryptophan or tyrosine, ultraviolet detection at 280 nanometres is insensitive, so chromatographic methods usually monitor absorbance near 214 nanometres, where the peptide backbone absorbs. Electrospray ionisation or matrix-assisted laser desorption/ionisation then checks the intact mass against the expected value near 390 daltons. Peptide mapping or amino acid analysis after acid hydrolysis can supplement these measurements, although such confirmatory work is seldom reported on commercial certificates of analysis.
Stability of the tetrapeptide follows ordinary peptide chemistry rather than any unusual structural feature. The aspartate-glycine pair is prone to aspartimide formation under mildly basic or neutral conditions, and deamidation can follow, altering both mass and chromatographic retention. Dry lyophilised powder kept at or below minus twenty degrees Celsius is the usual handling recommendation, with repeated freeze-thaw cycles avoided. Once dissolved in neutral aqueous buffer, degradation proceeds over days to weeks depending on pH and temperature, while acidic conditions generally slow the aspartimide route. A formal stability-indicating study has not been published in the indexed literature.
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.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography with ultraviolet detection, frequently near 214 nanometers where the peptide bond absorbs. Mass spectrometry, most often with electrospray ionization, confirms the observed molecular mass and helps separate the intact peptide from truncated or modified forms. Amino acid analysis or tandem mass spectrometry can establish residue order. Purity is commonly quoted as an area percentage, yet such values are method-dependent, and comparisons between laboratories require matching column, gradient and detection wavelength.
== Contraindications == Apomorphine is contraindicated when used concomitantly with serotonin 5-HT3 receptor antagonists, including ondansetron, granisetron, and palonosetron, as this combination has been associated with profound hypotension and loss of consciousness. It is also contraindicated with allergies to the drug or its excipients, including sulfites. Intravenous administration of apomorphine is associated with blood clots and pulmonary embolism due to crystallization in the vein and is not recommended.
== EMAIL invention controversy == Ayyadurai is notable for his widely disputed claim of being the "inventor of email". His claim is based on an electronic mail software called EMAIL, an implementation of interoffice email system, which he wrote as a 14-year-old student at Livingston High School, New Jersey, in 1979. Initial reports that repeated Ayyadurai's assertion—from organizations such as The Washington Post and the Smithsonian Institution—were followed by public retractions. These corrections were triggered by objections from historians and ARPANET pioneers who cited the fact the history of email dated back to the early 1970s. Ayyadurai started a campaign in 2011 in which he rebranded himself as the "Inventor of Email"; according to a paper published in Information & Culture, he "provoked a dramatic succession of exaggerated claims, credulous reporters, retractions, and accusations that a cabal of industry insiders and corrupt Wikipedia editors are colluding to hide the truth." A November 2011 Time Techland interview by Doug Aamoth, entitled "The Man Who Invented Email", argued that EMAIL represented the birth of email "as we currently know it". In that interview, Ayyadurai recalled that Les Michelson, the former particle scientist at Brookhaven National Labs who assigned Ayyadurai the project, had the idea of creating an electronic mail system that uses the header conventions of a hardcopy memorandum. Ayyadurai recalled Michelson as saying: "Your job is to convert that into an electronic format.
The e-cigarette vapor is generated when the e-liquid is vaporized by the heating element or by other mechanical methods. The last step of vapor processing happens as the e-cigarette vapor passes through the main air passage to the user. For some advanced devices, before inhaling, the user can adjust the heating element temperature, air flow rate or other features. The liquid within the chamber of an e-cigarette is heated to roughly 100-250 °C to create an aerosolized vapor. This is thought to result in pyrolysis of the e-liquid and could also lead to decomposition of other liquid ingredients. The aerosol (mist) produced by an e-cigarette is commonly but inaccurately called vapor. In physics, a vapor is a substance in the gas phase whereas an aerosol is a suspension of tiny particles of liquid, solid or both within a gas. The power output of the e-cigarette is correlated to the voltage and resistance (P = V2/R, in watts), which is one aspect that impacts the production and the amount of toxicants of e-cigarette vapors. The power generated by the heating coil is not based solely on the voltage because it also relies upon the current, and the resultant temperature of the e-liquid relies upon the power output of the heating element. The production of vapor also relies upon the boiling point of the solvent. Propylene glycol boils at 188 °C, while glycerin boils at 290 °C. The higher temperature reached by glycerin may impact the toxicants emitted by the e-cigarette. The boiling point for nicotine is 247 °C.
to bring historians together and provide a forum for the exchange of views between them; to give a national direction to objective and scientific writing of history and to have rational presentation and interpretation of history; to promote, accelerate and coordinate research in history with special emphasis on areas that have not received adequate attention so far; to promote and coordinate a balanced distribution of research effort over different areas; and to elicit support and recognition for historical research from all concerned and ensure the necessary dissemination and use of results.
Sources: en.wikipedia.org
RC(O)CH2R' + SO2Cl2 → RC(O)CHClR' + HCl + SO2 It also chlorinates alkanes, alkenes, alkynes, aromatics, ethers (such as tetrahydrofuran) and epoxides. Such reactions occur under free radical conditions using an initiator such as AIBN. It convert thiols or disulfides into the corresponding sulfenyl chlorides:
=== Predators === Some species of bacteria kill and then consume other microorganisms; these species are called predatory bacteria. These include organisms such as Myxococcus xanthus, which forms swarms of cells that kill and digest any bacteria they encounter. Other bacterial predators either attach to their prey in order to digest them and absorb nutrients or invade another cell and multiply inside the cytosol. These predatory bacteria are thought to have evolved from saprophages that consumed dead microorganisms, through adaptations that allowed them to entrap and kill other organisms.
Helene Langevin is an American medical scientist who served as the Director of the National Center for Complementary and Integrative Health (NCCIH) at the National Institutes of Health (NIH) between November 2018 and November 2025. She was a professor in the University of Vermont College of Medicine's Department of Neurological Sciences. She is best known for characterizing certain cellular and mechanical effects of acupuncture. She was also a Professor in Residence of Medicine at Harvard Medical School, Brigham and Women's Hospital. Prior to working at NIH, Langevin was the Director of the Osher Center for Integrative Medicine, jointly owned by Brigham and Women's Hospital and Harvard Medical School. Langevin was the principal investigator of studies funded by the National Institutes of Health. The Boston Globe describes her as a "celebrity" in the world of acupuncture.
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.
The solid is kept cold, dry and dark, typically at minus twenty degrees Celsius, in a sealed container with desiccant. Dissolved material is kept refrigerated and used promptly. Freezing and thawing a solution repeatedly is avoided because it accelerates degradation.