Everything below concerns Tetrapeptide. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-07-26. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
The compound is generally presented as a synthetic fragment of epithalamin, a pineal gland extract investigated in the former Soviet Union from the 1970s onward. Vladimir Khavinson and colleagues in Saint Petersburg developed short peptides modelled on such extracts, and epitalon became the most widely cited of those sequences. Most primary reports appeared in Russian-language journals or in proceedings with limited international circulation. Independent replication in laboratories outside that network remains sparse, and much repeated secondary material traces back to a small number of originating groups.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C14H22N4O9 | Computed for the free acid of Ala-Glu-Asp-Gly |
| Molecular mass | About 390.35 g/mol | Free peptide; salt forms shift the value |
| Appearance | White to off-white solid | Typical of short peptides after freeze-drying |
| Solubility class | Freely soluble in water | Aqueous buffers are also commonly used |
| Common synonyms | Epitalon, epithalone, AEDG | AEDG is the single-letter sequence |
The published literature is dominated by a small number of research groups, much of it in Russian-language journals, and independent replication outside those groups is limited. Studies are typically small, use cultured cells or rodent models, and report endpoints that differ between papers, which makes comparison difficult. Large randomised human trials have not appeared in the indexed literature. Questions about absorption, distribution and clearance are therefore still treated as open in reviews that mention the compound.
Epitalon is a synthetic tetrapeptide with the sequence alanine–glutamate–aspartate–glycine, commonly abbreviated AEDG. Its design traces to epithalamin, a peptide fraction prepared from bovine pineal gland extracts that researchers in Saint Petersburg began investigating in the 1970s. The compound has a molecular formula of C14H22N4O9 and a nominal molecular mass near 390 daltons. It holds no approved drug status in the United States or the European Union, and material sold under this name is generally offered as a research chemical rather than a finished pharmaceutical product.
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.
Epitalon is a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, commonly abbreviated AEDG. It was designed at the St. Petersburg Institute of Bioregulation and Gerontology as a short, chemically defined analogue of epithalamin, a fraction obtained from bovine pineal tissue. Small peptide bioregulators of this type formed a long-running line of work there from the 1980s onward. Because the molecule is produced by solid-phase synthesis rather than extraction, its composition is exact and its purity can be measured directly.
The most frequently cited proposed action is induction of telomerase, the enzyme that adds repeat sequences to chromosome ends. Cell-culture work from the originating group reported higher telomerase reverse transcriptase expression and measurable telomere elongation in human somatic cells after exposure. How a four-residue peptide would reach nuclear gene regulation is not established, and no cell-surface receptor or uptake route has been identified. Additional reports describe changes in melatonin secretion, antioxidant enzyme activity and lipid peroxidation in aged animals, but these findings remain mechanistically unconnected to the telomerase observation.
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.
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.
{\displaystyle (\mathbf {u} _{1}\times \mathbf {u} _{2})\times (\mathbf {u} _{2}\times \mathbf {u} _{3})=[(\mathbf {u} _{2}\times \mathbf {u} _{3})\cdot \mathbf {u} _{1}]\mathbf {u} _{2}-[(\mathbf {u} _{2}\times \mathbf {u} _{3})\cdot \mathbf {u} _{2}]\mathbf {u} _{1}=[(\mathbf {u} _{2}\times \mathbf {u} _{3})\cdot \mathbf {u} _{1}]\mathbf {u} _{2}}
In order to establish itself as an American empire, Spain had to fight against the relatively powerful civilizations of the New World. The Spanish conquest of the indigenous peoples in the Americas included using the Natives as forced labour. The Spanish colonies were the first Europeans to use African slaves in the New World on islands such as Cuba and Hispaniola. It was argued by some contemporary writers to be intrinsically immoral. Bartolomé de las Casas, a 16th-century Dominican friar and Spanish historian, participated in campaigns in Cuba (at Bayamo and Camagüey) and was present at the massacre of Hatuey; his observation of that massacre led him to fight for a social movement away from the use of natives as slaves. Also, the alarming decline in the native population had spurred the first royal laws protecting the native population. The first African slaves arrived in Hispaniola in 1501. This era saw a growth in race-based slavery. England played a prominent role in the Atlantic slave trade. The "slave triangle" was pioneered by Francis Drake and his associates, though English slave-trading would not take off until the mid-17th century. Many whites who arrived in North America during the 17th and 18th centuries came under contract as indentured servants. The transformation from indentured servitude to slavery was a gradual process in Virginia.
MSC-1 measured the electrostatic charge in the spacecraft. MSC-2 was a proton-electron spectrometer. MSC-3 was a tri-axis magnetometer. MSC-10 involved the crew photographing the red-blue Earth limb. Photographs were taken over the Middle East and the southwestern United States; several air fields indicated on charts were identified. The crew had 16 freeze-dried meals and ate all but one of them. As they lacked any means of measuring water intake, they attempted to minimize consumption of it and also reported high amounts of gas bubbles in the water from the water dispenser. They experienced a degree of eye, nose, and throat irritation early in the flight and post-landing. This was attributed to ammonia fumes from the flame retardant used in the cabin, which was changed to a different material on subsequent flights.
== Epidemiology == Donohue syndrome is an extremely rare disorder that occurs in one of every million births worldwide. Several dozen cases have been reported in the medical community, and in the reported cases of the disorder, it has been found that the females are twice as likely to have the disorder as men.
Sources: en.wikipedia.org
A PEGylated lipid is used as an excipient in both the Moderna vaccine and the Pfizer–BioNTech COVID-19 vaccine. Both RNA vaccines consist of Messenger RNA, or mRNA, encased in a bubble of oily molecules called lipids. Proprietary lipid technology is used for each. In both vaccines, the bubbles are coated with a stabilizing molecule of polyethylene glycol. As of December 2020, there is some concern that PEG could trigger an allergic reaction, as appears to have occurred by 19 December, in at least three "Alaska health care worker" people who were administered the Pfizer–BioNTech COVID-19 vaccine. The particular PEGylated molecule in the Moderna vaccine is known as DMG-PEG 2000. Pegvaliase (Biomarin) – PEGylated recombinant phenylalanine ammonia-lyase for the treatment of Phenylketonuria, approved by the FDA for the US in May 2018. Adynovate – PEGylated Antihemophilic Factor VIII for the treatment of patients with hemophilia A. (Baxalta, 2015) Irinotecan liposome (Onivyde) – PEGylated liposomal irinotecan hydrochloride trihydrate for the treatment of metastatic pancreatic cancer in adults proceeding treatment with gemcitabine-based therapy. (Ipsen, 2015) Plegridy – PEGylated Interferon Beta-1a for the treatment of patients with relapsing forms of multiple sclerosis. (Biogen, 2014) Naloxegol (Movantik) – PEGylated naloxol for the treatment of opioid-induced constipation in adults patients with chronic non-cancer pain (un-pegylated methadone can cause adverse gastrointestinal reactions).
Anaerobic growth: Positive Voges Proskauer test: Positive Acid produced from D-glucose: Positive L-arabinose: Negative D-xylose: Negative D-mannitol: Negative Starch hydrolysis: Positive Nitrate reduction: Positive Degradation of tyrosine: Positive Growth at above 50 °C: Negative Use of citrate: Positive The Central Public Health Laboratory in the United Kingdom tests for motility, hemolysis, rhizoid growth, susceptibility to γ-phage, and fermentation of ammonium salt-based glucose but no mannitol, arabinose, or xylose.
==== Gastrointenstinal tract ==== Age-related changes in OPRK1 gene expression were observed in mouse gastrointestinal tract, with mRNA expression significantly decreased in the distal ileum in 12-month-old mice compared to 6-month-old animals, though no statistically significant differences were detected in the stomach and colon. Protein expression of dynorphin in the colon was lower in older mice.
== History == DOBU was first described in the literature by Alexander Shulgin in 1970. Subsequently, it was described in greater detail by Shulgin in his book PiHKAL (Phenethylamines I Have Known and Loved) in 1991.
In 2003, Bakker began broadcasting The Jim Bakker Show daily at Studio City Café in Branson, Missouri, with his second wife Lori; it has been carried on CTN, Daystar, Folk TV, Grace Network (Canada), Daystar Television Canada, GEB America, Hope TV (Canada), Impact Network, WGN, WHT, TCT Network, The Word Network, UpliftTV, and ZLiving networks. Most of Bakker's audience receives his program on DirecTV and Dish Network. Bakker condemned the prosperity theology in which he took part earlier in his career, and has embraced apocalypticism. His show has a millennial, survivalist focus and sells buckets of freeze-dried food, such as beans on toast, to his audience in preparation for the end of days. Elspeth Reeve wrote in The Atlantic that Bakker's "doomsday survival gear" is overpriced. A man named Jerry Crawford, who credits Bakker with saving his marriage, invested $25 million in a new ministry for Bakker in Blue Eye, Missouri, named Morningside USA. Production for The Jim Bakker Show moved to Morningside in 2008.
Sources: en.wikipedia.org
Reagent co-flow and droplet fusion methods are tied to droplet formation events which lack downstream flexibility. To decouple reagent addition from droplet creation, a setup where reagent stream flows through a channel perpendicular to the droplet stream is utilized. An injection droplet is then merged with the plug as it passes the channel. Reagent volume is controlled by the flow rate of the perpendicular reagent channel. An early challenge for such systems is that reagent droplet merging was not reproducible for stable emulsions. By adapting the use of an actuated electric field into this geometry, Abate et al. achieved sub-picoliter control of reagent injection. This approach, termed picoinjection, controls injection volume through reagent stream pressure and droplet velocity. Further work on this method has aimed to reduce pressure fluctuations that impede reproducible injections. Injection of the pressurized aqueous fluid occurs when the electrodes are activated creating an electric field that destabilizes the aqueous fluid/oil interface, triggering the injection. Key advantages of picoinjection include low inadvertent material transfer between droplets and maintenance of droplet compartmentalization through the injection, however, electrodes are often fabricated using metal-solder which can complicate construction of the microfluidic device through increased fabrication time as a result of a more intricate design.
VOCs are also found in hospital and health care environments. In these settings, these chemicals are widely used for cleaning, disinfection, and hygiene of the different areas. Thus, health professionals such as nurses, doctors, sanitation staff, etc., may present with adverse health effects such as asthma; however, further evaluation is required to determine the exact levels and determinants that influence the exposure to these compounds. Concentration levels of individual VOCs such as halogenated and aromatic hydrocarbons vary substantially between areas of the same hospital. Generally, ethanol, isopropanol, ether, and acetone are the main compounds in the interior of the site. Following the same line, in a study conducted in the United States, it was established that nursing assistants are the most exposed to compounds such as ethanol, while medical equipment preparers are most exposed to 2-propanol. In relation to exposure to VOCs by cleaning and hygiene personnel, a study conducted in 4 hospitals in the United States established that sterilization and disinfection workers are linked to exposures to d-limonene and 2-propanol, while those responsible for cleaning with chlorine-containing products are more likely to have higher levels of exposure to α-pinene and chloroform.
CASP, which stands for Critical Assessment of Techniques for Protein Structure Prediction, is a community-wide experiment for protein structure prediction taking place every two years since 1994. CASP provides with an opportunity to assess the quality of available human, non-automated methodology (human category) and automatic servers for protein structure prediction (server category, introduced in the CASP7). The CAMEO3D Continuous Automated Model EvaluatiOn Server evaluates automated protein structure prediction servers on a weekly basis using blind predictions for newly release protein structures. CAMEO publishes the results on its website.
Biotechnology encompasses a wide range of procedures for modifying living organisms for human purposes, going back to domestication of animals, the cultivation of plants, and "improvements" to these through breeding programs that employ artificial selection and hybridization. Modern usage also includes genetic engineering, as well as cell and tissue culture technologies. The American Chemical Society defines biotechnology as the application of biological organisms, systems, or processes by various industries to learning about the science of life and the improvement of the value of materials and organisms, such as pharmaceuticals, crops, and livestock. As per the European Federation of Biotechnology, biotechnology is the integration of natural science and organisms, cells, parts thereof, and molecular analogues for products and services. Biotechnology is based on the basic biological sciences (e.g., molecular biology, biochemistry, cell biology, embryology, genetics, microbiology) and conversely provides methods to support and perform basic research in biology.
Sources: en.wikipedia.org
It is a four-amino-acid peptide with the sequence alanine-glutamate-aspartate-glycine. The chain is unmodified and contains only standard proteinogenic residues, which makes it straightforward to produce by solid-phase synthesis and to characterise by standard peptide methods.
Epitalon and epithalon both circulate, and the difference reflects transliteration of a name coined in Russian-language publications. Reference to the extract it derives from, epithalamin, explains the shared stem. Databases and suppliers are inconsistent, so a search for one spelling alone may miss relevant entries.
No. Epithalamin is a multi-component preparation obtained from pineal tissue, and its exact composition is not fully characterised. Epitalon is a single defined tetrapeptide described as a short synthetic counterpart of that extract, so the two are related in origin but not interchangeable in identity.
The usual approach is reversed-phase HPLC with ultraviolet detection, reported as a percentage of total peak area. Mass spectrometry is used alongside chromatography to confirm identity rather than purity alone.