If you have been reading about reversed-phase HPLC and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Updated 2026-04-13. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
| 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 |
Identity and purity of epitalon samples are normally established by reversed-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres, combined with mass spectrometry. The mass spectrum confirms the expected molecular ion and can reveal truncated or oxidised by-products. Amino acid analysis after acid hydrolysis verifies that the four residues are present in the expected ratio. Certificates typically report a purity figure taken from chromatographic peak area, expressed as a percentage of total integrated signal.
Lyophilised epitalon is generally held at minus twenty degrees Celsius in a sealed container kept dry and dark. Cooler conditions are sometimes recommended for long-term archives. The solid takes up moisture readily enough that repeated opening of a vial introduces water, so dividing a batch into smaller portions before storage lowers degradation risk. Aqueous solutions are less durable than the dry powder and are usually prepared shortly before use, then kept cold and shielded from light to slow hydrolysis and oxidation.
Verification of research-grade material involves comparing a supplier chromatogram against an in-house reference, checking the observed mass against the calculated value, and where possible confirming residue order by tandem mass spectrometry or enzymatic peptide mapping. Purity claims should be read alongside the method used to obtain them, because detection wavelength and integration settings alter the result. Batch-specific data, rather than a generic grade statement, is the informative part of a certificate.
Peptides of this size are generally stable as dry solids but degrade in solution over time. The principal routes are hydrolysis of the peptide backbone and oxidation, with hydrolysis favoured by elevated temperature and extreme pH. Aqueous solutions held at room temperature can show measurable loss of purity within days, while frozen aliquots are considerably more durable. Because the sequence contains neither cysteine nor methionine, oxidation is less of a concern than for many other peptides, but pH control during handling still matters.
Typical storage for the lyophilized powder is −20 °C or lower, in a sealed container protected from light and moisture. Hygroscopic material should be allowed to equilibrate to room temperature before the vial is opened, which limits condensation on the contents. Working solutions are commonly divided into single-use aliquots and frozen to avoid repeated freeze-thaw cycles. Dilute solutions are more prone to adsorption onto plastic surfaces and to loss during filtration, so procedures that minimize transfers and use low-binding labware are preferable.
Reversed-phase high-performance liquid chromatography is the standard approach for assessing purity, usually with ultraviolet detection near 214 nm, where the peptide bond absorbs. Mass spectrometry, most often with electrospray ionization, confirms the molecular mass and helps reveal truncation or deletion byproducts. Amino acid analysis can verify composition, and counterion content is sometimes measured because peptides purified with trifluoroacetic acid retain variable amounts of that salt. Purity figures reported without a stated method and detection wavelength are difficult to interpret.
Atomoxetine contains an aryloxy propylamine moiety that has been linked to monoamine reuptake inhibitory activity. It's selectivity to the norepinephrine transporter (NET) is due to its methyl substituent in the 2' position on the phenyl ring. Research has shown that a methyl group in position 2' provides more affinity towards NET than a methoxy group in the same position. The amine group of atomoxetine binds to the amino acids of NET with a salt bridge and hydrogen bonds while the phenyl and methylphenyl groups have hydrophobic interactions. Reboxetine has two chiral centers and the active ingredient is a mixture of the (R,R)-(-)- and (S,S)-(+) enantiomers. Reboxetine, like atomoxetine, contains an aryloxy propylamine moiety and has an ethoxy group in position 2' on the phenyl ring. But the main difference from atomoxetine is the morpholine group instead of a secondary amine. The morpholine group of reboxetine forms a salt bridge and hydrogen bonds with the amino acids of NET. While the phenyl and ethyloxyphenyl groups form hydrophobic interactions. The aryloxy propylamine moiety is also found in many other monoamine reuptake inhibitors, but the placement of substituents on the phenyl ring determine the selectivity. Compounds with substituents in position 2' have selectivity for NET. Compounds with substituents in position 4' are selective serotonin reuptake inhibitors e.g. fluoxetine and paroxetine. Then there is duloxetine which has a phenyl group attached at positions 2' and 3' and has a similar affinity for both transporters.
==== Native Hawaiian or other Pacific Islander ==== The obesity rate for Native Hawaiian or other Pacific Islander adults (over 30 BMI) in the US in 2015 was 33.4%. No breakdown by sex was given for Native Hawaiian or other Pacific Islander adults in the CDC figures.
==== Gastrointestinal bleeding ==== The most common cause of iron deficiency anemia in men and post-menopausal women is gastrointestinal bleeding. There are many sources of gastrointestinal tract bleeding, including the stomach, esophagus, small intestine, and the large intestine (colon). Gastrointestinal bleeding can result from regular use of some medications, such as non-steroidal anti-inflammatory drugs (e.g. aspirin), as well as antiplatelets such as clopidogrel and anticoagulants such as warfarin; however, these are required in some patients, especially those with states causing a tendency to form blood clots. Colon cancer, which typically occurs in older individuals, is another potential cause of gastrointestinal bleeding. In addition, some bleeding disorders, such as von Willebrand disease and polycythemia vera, can cause gastrointestinal bleeding.
The Emperor Naruhito and Empress Masako of Japan begin a three-day state visit to the United Kingdom by meeting the King and Queen Camilla. 26 June The media is allowed to report that Constance Marten and Mark Gordon were convicted of concealing the birth of a child and preventing the course of justice after reporting restrictions are lifted. The pair also face a retrial for manslaughter provisionally scheduled to begin in March 2025 and will remain in custody until then. An inquest jury finds that failures "across multiple agencies" contributed to the death of Zara Aleena, who was sexually assaulted and murdered in June 2022 as she walked home from a night out. 2024 United Kingdom general election betting scandal: Alex Cole-Hamilton, leader of the Scottish Liberal Democrats, admits to placing bets on Scottish Liberal Democrat election candidates, but says he did not place bets on the date of the election itself. The Sun reports that Sir Philip Davies, the Conservative candidate for Shipley, allegedly placed an £8,000 bet on whether he would lose his seat at the election, which has a majority of 6,242. 27 June The first death from the E. coli outbreak is reported, as the number of confirmed cases reaches 275. The Metropolitan Police says that at least seven police officers are now being investigated for placing bets on the date of the general election. 28 June Revised data from the Office for National Statistics shows the UK economy grew by 0.7% in the first three months of 2024 as the UK emerged from a recession; the figures are slightly better than the original forecast.
Sources: en.wikipedia.org
Nearer Secret of Life." The news reached readers of The New York Times the next day; Victor K. McElheny, in researching his biography, "Watson and DNA: Making a Scientific Revolution", found a clipping of a six-paragraph New York Times article written from London and dated 16 May 1953 with the headline "Form of 'Life Unit' in Cell Is Scanned". The article ran in an early edition and was then pulled to make space for news deemed more important. (The New York Times subsequently ran a longer article on 12 June 1953). The university's undergraduate newspaper Varsity also ran its own short article on the discovery on Saturday 30 May 1953. Bragg's original announcement of the discovery at a Solvay conference on proteins in Belgium on 8 April 1953 went unreported by the British press. In a seven-page, handwritten letter to his son at a British boarding school on 19 March 1953 Crick explained his discovery, beginning the letter "My Dear Michael, Jim Watson and I have probably made a most important discovery". The letter was put up for auction at Christie's New York on 10 April 2013 with an estimate of $1 to $2 million, eventually selling for $6,059,750, the largest amount ever paid for a letter at auction. Sydney Brenner, Jack Dunitz, Dorothy Hodgkin, Leslie Orgel, and Beryl M Oughton, were some of the first people in April 1953 to see the model of the structure of DNA, constructed by Crick and Watson; at the time they were working at Oxford University's Chemistry Department.
Half-Life: Echoes – Having a greater emphasis on survival horror than the base game, the player controls an unnamed scientist at the Black Mesa Research Facility surviving the Resonance Cascade and invasion by Xen and HECU forces. Point of View – A mod released on May 2, 2003 by the developers of Azure Sheep. The player character is a vortigaunt named Xonxt. The player can only use alien weaponry and has no armor. Medkits can't be used, instead Xen healing pools have to be used for restoring health. The Games Machine gave the mod a positive review. PC Zone gave the mod a rating of 76 out of 100 and called it "a refreshing alternative". Poke646 – Released in December 2001. Takes place after the events of Half-Life in Nation City. Features new weapons and textures. Named often one of the best single-player mods for Half-Life. Poke646: Vendetta – Released in December 2006. Sequel to Poke646. Received a positive review by PC Action. They Hunger – This is a single-player horror-based mod. It was released by Neil Manke's Black Widow Games in three episodes, the first in 1999, the second in 2000, and the final installment in 2001. All three were at one point bundled with PC Gamer magazine. USS Darkstar – A mod by Neil Manke, produced by PC Gamer and released on July 14, 1999. This mod follows a scientist on a deep-space scientific mission aboard an interstellar spacecraft. When an experiment goes awry, the player has to defend himself against aliens. The mod was first released on the PC Gamer website and was featured on the magazine's demo CD in August 1999.
In accordance, studies of the amount of oral estradiol necessary for endometrial proliferation in women have reported a total dose of 60 mg for micronized estradiol relative to 120 to 300 mg or more for non-micronized estradiol. As such, micronization has been said to substantially improve the potency of oral estradiol.
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.
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.