If you have been reading about telomerase 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.
Last reviewed on 2026-07-06. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
Discussions in the literature often conflate three distinct entities: the pineal extract epithalamin, the isolated tetrapeptide AEDG, and commercial preparations sold under similar names. Reviews citing older Russian-language studies sometimes omit detail on purity, route of administration and control groups, which makes cross-study comparison difficult. Researchers working with the compound generally note the need for independent replication, standardized enzyme assays, and clearer reporting of peptide identity. These caveats are relevant when weighing claims that appear in secondary sources rather than in primary reports.
（TG:@pojiaai）Epitalon is a synthetic linear tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, abbreviated AEDG. It emerged from work on epithalamin, a peptide fraction prepared from bovine pineal tissue, and was designed as a short, chemically defined analogue of that extract. Early publications came mainly from Russian laboratories studying pineal peptides and aging-related endpoints. The compound appears in the literature under several spellings, including epithalon and epithalone, which complicates systematic searching. Its small size makes solid-phase assembly and routine analytical characterization straightforward.
| Property | Value | Notes |
|---|---|---|
| Analytical method | Reversed-phase HPLC | Purity determination, typically 214 nm |
| Mass confirmation | ESI or MALDI mass spectrometry | Compared with mass near 390 Da |
| Common synonyms | Epitalon, epithalon, AEDG | Naming differs between suppliers |
| Storage temperature | −20 °C or lower | Lyophilised powder, kept desiccated |
| Solution stability | Limited in neutral aqueous buffer | Aspartimide and hydrolysis pathways |
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.
Residue composition is the property that most cleanly separates verified material from mislabelled samples. Alanine, glutamate, aspartate and glycine appear in that order from the N-terminus, and the two acidic residues sit in the middle of the chain. Because the peptide is short, it can be produced by solid-phase synthesis and characterised by mass spectrometry without ambiguity. Any reported sample whose measured mass departs substantially from 390 daltons is a different compound or a degraded mixture rather than epitalon.
Epitalon is a synthetic tetrapeptide whose four residues are alanine, glutamate, aspartate and glycine, commonly abbreviated AEDG. Its molecular formula is C14H22N4O9 and its monoisotopic mass is near 390.35 daltons. The peptide carries two acidic side chains, so it is neutral to negatively charged in most aqueous buffers. Published reference summaries usually list it under both spellings, epitalon and epithalon, and treat the two names as the same material.
The compound is generally described as a synthetic analogue of a fragment isolated from a pineal gland extract. Researchers associated with the Saint Petersburg Institute of Bioregulation and Gerontology introduced it during the 1980s and 1990s while studying short peptides from animal tissue. The original extract, called epithalamin, is a heterogeneous mixture, whereas epitalon is a single defined sequence. That distinction matters because findings reported for the extract are not automatically findings about the pure tetrapeptide, and claims about broader biological effects remain a separate question from the chemical identity described here.
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.
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.
Laboratory work has examined effects on telomerase activity in cultured cells, on melatonin rhythms in animals, and on markers of oxidative stress. Some experiments report measurable changes while others show none, and the reported findings rest largely on small studies. The absence of large independent trials means the generality of these results is unresolved rather than settled. Review articles occasionally apply the label geroprotector, a term that reflects a research hypothesis about ageing rather than an established clinical finding.
Epitalon is the common name for a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, usually abbreviated AEDG. All four residues are proteinogenic amino acids, and the free peptide has a calculated mass near 390 grams per mole. Because the chain is short and carries no modifications, it is assembled readily by solid-phase synthesis and is distributed mainly as a freeze-dried solid for laboratory work. Catalogue listings use the spellings epitalon, epithalone, and simply AEDG, and the three refer to the same sequence.
Most members of the 102d Regiment of Foot embarked for England in May 1810. Upon arrival, a majority went to veteran or garrison battalions, most officers ending up in the 8th Royal Veteran Battalion. The regiment was reconstituted with new recruits, including 150 men "of free birth and good character" born in the colony of New South Wales, after it arrived at its new base in Horsham in October 1810. It was sent to Guernsey in July 1811. The regiment was posted to the Bermuda Garrison, stationed at St. George's Garrison in 1812, this being part of the Nova Scotia Command, co-inciding with the start of the War of 1812.
== Chemistry == Selenocysteine is the Se-analogue of cysteine. It is rarely encountered outside of living tissue (nor is it available commercially) because of its high susceptiblility to air-oxidation. More common is the oxidized derivative selenocystine, which has an Se-Se bond. Both selenocysteine and selenocystine are white solids. The Se-H group is more acidic (pKa = 5.43) than the thiol group; thus, it is deprotonated at physiological pH.
== As a drug target == With its integral role in HIV replication, HIV protease has been a prime target for drug therapy. HIV protease inhibitors work by specifically binding to the active site by mimicking the tetrahedral intermediate of its substrate and essentially becoming “stuck,” in the catalytic cycle, disabling the enzyme. After assembly and budding, viral particles lacking active protease cannot mature into infectious virions. Several protease inhibitors have been licensed for HIV therapy. There are ten HIV-1 PR inhibitors that are currently approved by the Food and Drug Administration: indinavir, saquinavir, ritonavir, nelfinavir, lopinavir, amprenavir, fosamprenevir, atazanavir, tipranavir, and darunavir. Many of the inhibitors have different molecular components and thus different mechanistic actions, such as blocking the active site. Their functional roles also extend to influencing circulation concentrations of other inhibitor drugs (ritonavir) and being used only for certain circumstances in which the virus exhibits tolerance of other inhibitors (tipranavir).
This made slaves a permanent part of a master's lineage and the children of slaves could become closely connected with the larger family ties. Children of slaves born into families could be integrated into the master's kinship group and rise to prominent positions within society, even to the level of chief in some instances. However, stigma often remained attached and there could be strict separations between slave members of a kinship group and those related to the master. Slavery was practiced in many different forms: debt slavery, enslavement of war captives, military slavery, and criminal slavery were all practiced in various parts of Africa. Slavery for domestic and court purposes was widespread throughout Africa.
==== Russian ==== Russian Brotherhood Organization of the U.S.A. - Founded in 1900, incorporated 1903. Headquarters in Philadelphia. National convention meets quadrennially. 365 lodges in 1975, and 386 lodges in 1972. Mid-1960s membership 12,000; 9,000 members in 1978, 7,832 in 1995. Many lodges attached to orthodox churches. Mostly concentrated in New York, New Jersey, Connecticut, Pennsylvania, and Ohio. Grants scholarships and helps parochial schools; organize choral groups, balalaika orchestras, and folk dancing. Built cultural and sports centers. Russian Independent Mutual Aid Society - Founded in 1931. Operates mainly in Illinois and Michigan. 1,475 members in 1965, less than 900 in 1978, 789 in 1989, and 825 in 1995. Headquarters in Chicago. Lodges are called "branches", and biannual national conventions. Works closely with Russian Orthodox Church, supports the study of Russian language, music, folk dances, and customs; sponsors concerts, dramatic presentations, picnics, and banquets. Russian Orthodox Catholic Mutual Aid Society of the USA - Founded in 1895. Headquarters in Wilkes-Barre, Pennsylvania. Conventions every four years. In 1965 it had 2,777 members in 170 local lodges, in 1978 1,500 in 152 lodges. Had only 1,510 members in 1995. Closely associated with the church, and contributes to its theological seminaries, aids boy and girl scouts, and the Red Cross. Russian Orthodox Catholic Womens Mutual Aid Society - Founded in 1907. Headquarters in Pittsburgh. Had 50 lodges, all of them in Pennsylvania in 1979. 1965 membership 2,425, 1978 membership 1,700.
Sources: en.wikipedia.org
=== Surgical anatomy for nasal reconstruction === The human nose is a sensory organ that is structurally composed of three types of tissue: (i) an osseo-cartilaginous support framework (nasal skeleton), (ii) a mucous membrane lining, and (iii) an external skin. The anatomic topography of the human nose is a graceful blend of convexities, curves, and depressions, the contours of which show the underlying shape of the nasal skeleton. Hence, these anatomic characteristics permit dividing the nose into nasal subunits: (i) the midline (ii) the nose-tip, (iii) the dorsum, (iv) the soft triangles, (v) the alar lobules, and (vi) the lateral walls. Surgically, the borders of the nasal subunits are ideal locations for the scars, whereby is produced a superior aesthetic outcome, a corrected nose with corresponding skin colors and skin textures.
== Operations == A&W is the only major fast-food chain in the United States to be owned entirely by franchisees since the 2011 sale from Yum! Brands to A Great American Brand, LLC., which is mostly under the control of the National A&W Franchisee Association (NAWFA). The current owners rely heavily on single-brand restaurants, in contrast to combined, co-branded restaurants, which came from prior administrations. As of December 2021, there were 900 restaurants in the US and Asia. In the United States alone, the states with the most restaurants are California, followed by Wisconsin and Michigan. As of year-end 2023, A&W has 455 franchised restaurants in the US market alone. The number of co-branded locations has been on the decline with 243 such units. As of January 2025, A&W has made it to the Franchise 500 list for six consecutive years, standing at 210th place in the 2024 ranking. The number of restaurants in the United States and in Asia is almost equiparable, with the chain steadily decreasing its number of units in the United States and increasing elsewhere, a trend that has been following since 2015.
=== Use of social media networks === Almost all Americans who were in their teens and 20s during the late 2010s and early 2020s are on at least one social-media platform. YouTube was the most popular in 2024, followed by TikTok, Instagram, and Snapchat. Meanwhile, Facebook and Twitter have lost grounds among teenagers compared to the 2010s. About three quarters checked their accounts multiple times a day. Members of Generation Z are more likely to "follow" others on social media than "share" and use different types of social media for different purposes. Very few expressed concern about third parties being able to access their data as they share more personal information more often compared to previous generations. Most have uploaded photographs of themselves, stated their interests, given their school names, posted their locations, and revealed their relationship statuses. As a cohort, Generation Z finds validation and social support on social media, where they develop their own individual identities. On the other hand, only a minority engaged in political conversations on social media networks. Despite their heavy usage of social media, a majority believe that life was better before the emergence of these platforms.
The proportion of AST to ALT in hepatocytes is about 2.5:1, but because AST is removed from serum by the liver sinusoidal cells twice as quickly (serum half-life t1/2 = 18 hr) compared to ALT (t1/2 = 36 hr), so the resulting serum levels of AST and ALT are about equal in healthy individuals, resulting in a normal AST/ALT ratio around 1. An AST/ALT ratio >5 necessarily involves extrahepatic tissue, as death of hepatocytes alone would produce an AST/ALT ratio no greater than 2.5. Because the primary cause is extrahepatic, typically an isolated elevated AST is seen, with no change in ALT. Common causes include bone disease, chronic renal failure, lymphoma, and congestive heart failure. When hepatocellular death is increased beyond the usual "background" levels, the serum levels of AST compared to ALT tend to reflect the cellular proportions, yielding AST that is over twice as prevalent as ALT (AST/ALT >2) in conditions with chronic, constant hepatocyte damage (such as alcoholic hepatitis, hepatocellular carcinoma) and during early-stage acute liver damage (such as viral hepatitis). In late-stage acute liver damage, the body has had adequate time to clear AST, but not ALT, often resulting in an AST/ALT <1. Since testing typically occurs late in acute viral hepatitis, it is conventionally associated with an AST/ALT ratio <1, though early in the disease, the AST/ALT ratio is often elevated. As the acute liver damage resolves, the body has more time to clear ALT, so in the absence of chronic liver disease, the AST/ALT ratio gradually returns to baseline levels.
At 200–300 °C, if oxygen has not been excluded, the carbonaceous residue may start to burn, in a highly exothermic reaction, often with no or little visible flame. Once carbon combustion starts, the temperature rises spontaneously, turning the residue into a glowing ember and releasing carbon dioxide and/or monoxide. At this stage, some of the nitrogen still remaining in the residue may be oxidized into nitrogen oxides like NO2 and N2O3. Sulfur and other elements like chlorine and arsenic may be oxidized and volatilized at this stage. Once combustion of the carbonaceous residue is complete, a powdery or solid mineral residue (ash) is often left behind, consisting of inorganic oxidized materials of high melting point. Some of the ash may have left during combustion, entrained by the gases as fly ash or particulate emissions. Metals present in the original matter usually remain in the ash as oxides or carbonates, such as potash. Phosphorus, from materials such as bone, phospholipids, and nucleic acids, usually remains as phosphates.
Sources: en.wikipedia.org
== External links == Clinical trial number NCT01340872 for "Safety and Efficacy Study of Oral Ferric Iron To Treat Iron Deficiency Anaemia in Quiescent Ulcerative Colitis (AEGIS-1) (AEGIS-1)" at ClinicalTrials.gov Clinical trial number NCT01352221 for "Safety and Efficacy Study of Oral Ferric Iron To Treat Iron Deficiency Anaemia in Quiescent Crohn's Disease (AEGIS-2) (AEGIS-2)" at ClinicalTrials.gov Clinical trial number NCT02968368 for "Study With Oral Ferric Maltol for the Treatment of Iron Deficiency Anemia in Subjects With Chronic Kidney Disease (AEGIS-CKD)" at ClinicalTrials.gov Clinical trial number NCT05126901 for "Evaluate the Safety and Efficacy of Ferric Maltol Oral Suspension vs. Ferrous Sulfate Oral Liquid in Children and Adolescents Aged 2 to 17 Years With Iron-deficiency Anaemia, With a Single Arm Study in Infants Aged 1 Month to Less Than 2 Years (FORTIS)" at ClinicalTrials.gov
=== Chemical === The chemistry of nihonium is expected to be very different from that of thallium. This difference stems from the spin–orbit splitting of the 7p shell, which results in nihonium being between two relatively inert closed-shell elements (copernicium and flerovium). Nihonium is expected to be less reactive than thallium, because of the greater stabilisation and resultant chemical inactivity of the 7s subshell in nihonium compared to the 6s subshell in thallium. The standard electrode potential for the Nh+/Nh couple is predicted to be 0.6 V. Nihonium should be a rather noble metal. The metallic group 13 elements are typically found in two oxidation states: +1 and +3. The former results from the involvement of only the single p electron in bonding, and the latter results in the involvement of all three valence electrons, two in the s-subshell and one in the p-subshell. Going down the group, bond energies decrease and the +3 state becomes less stable, as the energy released in forming two additional bonds and attaining the +3 state is not always enough to outweigh the energy needed to involve the s-electrons. Hence, for aluminium and gallium +3 is the most stable state, but +1 gains importance for indium and by thallium it becomes more stable than the +3 state. Nihonium is expected to continue this trend and have +1 as its most stable oxidation state. The simplest possible nihonium compound is the monohydride, NhH. The bonding is provided by the 7p1/2 electron of nihonium and the 1s electron of hydrogen.
=== Retrospective === Retrospective reviews have typically been more appreciative. Craig Butler of AllMovie wrote that "Stone Cold might seem like a throwaway action film built around a sports personality but it's actually much more. In fact, this is a model b-movie". Of the cast, he said that "Bosworth acquits himself well as the hero" and "Lance Henriksen is charming and chilling", while "William Forsythe delivers a feral, rip-snorting turn". He also pointed that "Craig Baxley does an excellent job in the director's chair." Svet Atanasoff of Blu-ray.com deemed that "Stone Cold might be the ultimate macho action film". Not convinced by Bosworth's contention that the excision of its family themes doomed the film, he claimed that he had "always liked it". Ian Jane of DVD Talk commented that "Stone Cold may be dumber than a bag of rocks, and Brian Bosworth might have all the acting charisma of a corn flake, but hot damn if this movie isn't a fantastic slice of brainless action moviemaking done right." John Higgins of Starburst called it "a no-brainer of an action film, following a traditional template and with sufficient bang, clever editing and brutal violence to just carry it over the finish line." Comparing it to Brandon Lee's equally neglected Rapid Fire, he concluded that "it may be short on plot and character, but it is a highly effective action thriller".
DABA analogues A novel family of zinc-targeting diaminobenzoic acid (DABA) compounds were rationally designed and developed in 2013, displaying micromolar potency for ERAP1 inhibition (compound 2, IC50 = 2 μM, Table 1). Moderate selectivity over ERAP2 and IRAP with additional optimization efforts based on extensive investigation of SAR has been achieved.
=== Animal health === One meta-analysis published in 2003 suggested a negative impact of rBST's effects on bovine health. Findings suggested an average increase in milk output ranging from 11–16%, an approximate 24% increase in the risk of clinical mastitis, a 40% reduction in fertility, and 55% increased risk of developing clinical signs of lameness. The same study reported a decrease in body condition score for cows treated with rBST, though an increase in their dry matter intake occurred. Another meta-analysis (2003) reported on body condition scores (BCS) but could not reach a conclusion due to lack of homogeneity in study design and reporting. They found a trend towards decreased BCS in treated cows but state "Depending on the level of body condition in these cows, this effect may have been beneficial or detrimental." This analysis did not report on clinical mastitis. A more recent meta-analysis (2014) published by the Journal of the American Veterinary Medical Association showed no significant increase in risk of clinical mastitis nor other adverse effects on cow health and well-being. This review included 26 peer-reviewed studies that involved the use of the rBST-Zn formulation available to US producers in accordance with the label instructions for treatment initiation (57 to 70 days after birth), dose (500 mg, every 14 days), and route (subcutaneous). Mastitis has cost American dairy industries an estimated $1.5 to 2 billion per year in treating dairy cows.
Sources: en.wikipedia.org
The molecule lacks aromatic residues, so it absorbs weakly near 280 nanometres, the wavelength applied to many other peptides. The peptide bond absorbs strongly below 220 nanometres, making 214 nanometres a practical compromise. Gradient methods must therefore use mobile phases with low ultraviolet absorbance to keep the baseline clean.
Neutral and slightly basic aqueous conditions promote aspartimide formation at the aspartate-glycine step, often followed by deamidation. Elevated temperature and repeated freeze-thaw cycles accelerate the loss. Acidic solutions and dry lyophilised powder are comparatively stable over short periods.
No monograph exists in the United States Pharmacopeia or the European Pharmacopoeia, and no widely distributed certified reference standard is available. Purity and identity therefore rest on supplier methods that are not harmonised. This absence is the main reason reported purities are difficult to compare between sources.
It is a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, often abbreviated AEDG. The molecule is linear and contains no modified residues, so it is fully described by its sequence.