tetrapeptide raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2025-12-04. Anything still debated is marked as such rather than presented as settled.
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 peptide emerged from research carried out in Saint Petersburg from the late 1980s onward, where investigators searched for shorter active fragments of a pineal preparation known as epithalamin. The name epitalon was chosen to reflect that parent extract. Early reports described effects on neuroendocrine markers and on the lifespan of laboratory animals. Much of that work appeared in Russian-language journals, with English translations following later, which affects how readily the original protocols can be assessed by outside groups.
Published studies on epitalon are dominated by a small number of research groups, and independent replication in other laboratories remains limited. Proposed mechanisms include activation of telomerase and modulation of melatonin rhythms, but the evidence for either rests mainly on cell cultures and animal models. Whether the peptide produces comparable effects in humans is an open question, and the absence of large controlled trials means the literature is best read as exploratory rather than settled.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C14H22N4O9 | Calculated from the four residues with three water losses |
| Molecular mass | About 390.35 g/mol | Monoisotopic mass near 390.14, used for mass-spectrometric identification |
| Peptide sequence | Ala-Glu-Asp-Gly | Single-letter form AEDG; no disulfide bonds or modified residues |
| Appearance | White to off-white solid | Supplied as a dried powder |
| Isoelectric point | Around 4 | Estimated from aspartate and glutamate side-chain pKa values |
Published work on this compound consists mainly of in vitro experiments, animal studies, and small clinical investigations, a substantial share of which appeared in Russian-language journals. Sample sizes are generally small, control conditions differ between studies, and several endpoints rely on markers whose clinical meaning is itself debated. Reviews of the longevity field treat the peptide as an early example of telomerase-directed research rather than an established intervention. Regulatory treatment varies by country: some jurisdictions place it under prescription controls, others treat it as a laboratory material, and importation may be restricted regardless of local status.
Epitalon is a synthetic tetrapeptide whose sequence is alanine–glutamate–aspartate–glycine, commonly abbreviated AEDG. It was developed in Russia during the 1980s and 1990s by investigators associated with the St. Petersburg Institute of Bioregulation and Gerontology, who studied short peptides as regulators of gene expression and tissue function. The alternative spelling epithalon appears interchangeably in the literature, and the two names refer to the same molecule. Outside Russia it is encountered chiefly as a research chemical rather than a licensed medicine, and it holds no approval from the United States Food and Drug Administration or the European Medicines Agency.
The peptide is a synthetic analogue of epithalamin, a preparation extracted from bovine pineal glands. Investigators sought a short, chemically defined molecule that would reproduce some of the endocrine and gerontological observations attributed to the glandular extract. Proposed mechanisms centre on induction of telomerase activity, an effect reported in cultured human somatic cells in the early 2000s, together with influences on melatonin secretion and neuroendocrine regulation. Those mechanisms remain incompletely characterised, and the reported telomerase response has not been consistently reproduced by independent groups working in comparable systems.
Proposed mechanisms centre on cell-culture observations rather than a defined receptor interaction. Several reports describe increased expression of the telomerase catalytic subunit after exposure of cultured human cells, and the authors attributed the effect to short peptide fragments entering the nucleus and influencing gene transcription. No receptor for the tetrapeptide has been identified, and the free peptide is expected to be degraded rapidly by plasma peptidases. Whether any measurable fraction reaches intact tissues after administration remains an unresolved question rather than an established finding.
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.
== Medical uses == Cinnarizine is predominantly used to treat nausea and vomiting associated with motion sickness, vertigo, Ménière's disease, or Cogan's syndrome. It is one of only a few drugs that has a beneficial effect in the chronic treatment of the vertigo and tinnitus associated with Ménière's disease. In a clinical study (n=181), treatment with cinnarizine reduced the occurrence of moderate vertigo experience by 65.8% and extreme vertigo by 89.8%.
=== Muscle fiber growth === Muscle fibers grow when exercised and shrink when not in use. This is due to the fact that exercise stimulates the increase in myofibrils which increase the overall size of muscle cells. Well exercised muscles can not only add more size but can also develop more mitochondria, myoglobin, glycogen and a higher density of capillaries. However, muscle cells cannot divide to produce new cells, and as a result there are fewer muscle cells in an adult than in a newborn.
== Retail supplements == Pre-workout supplements are sold in a variety of retailers. The top-selling brands of pre-workout supplements in 2019 included Pre JYM Pre Workout by JYM Supplemental Science, ENGN Shred Pre Workout by EVLUTION Nutrition, and C4 Original Pre Workout by Cellucor. These brands were the top three in the overall bestseller category on leading bodybuilding informational website bodybuilding.com and Sports Illustrated. Some variations on common pre-workout products include sugar-free, creatine-free and stimulant-free options. The market size for pre-workout products was a $2.7 billion industry in 2008. In 2022 the market size for pre-workout had grown to $14.2 billion. Lack of regulation can mean that the ingredients used to prepare the product may not be of high quality and purity. This can mean the dose stated on the ingredients does not match the actual composition of the blend. Plant extracts in particular are often adulterated or of varying quality, but may be assumed by manufacturers to be pure and consistent. Also, protein powders used to prepare the blend may sometimes be contaminated with melamine, a plastic precursor which is sometimes added to produce false positive results for nitrogen content. Up to 50% of pre-workout blends analysed in one study were found to be contaminated with melamine.
Chidambaram issued clarifications, in the meantime, that the government was not against FIIs and was not immediately banning PNs. After the market opened at 10:55 am, the index staged a comeback and ended the day at 18715.82, down 336.04 from the last day's close. However, this would not be the end of the volatility. The next day (18 October 2007), the SENSEX tumbled by 717.43 points – 3.83 per cent – to close at 17,998.39 points. The slide continued the next day (19 October 2007), when the SENSEX fell 438.41 points to settle at 17,559.98 to the end of the week, after touching the lowest level of that week at 17,226.18 during the day. After detailed clarifications from the SEBI chief M. Damodaran regarding the new rules, the market made an 879-point gain on 23 October, thus signalling the end of the PN crisis.
Sources: en.wikipedia.org
== External links == Prof. Matthias Tschöp (16 May 2012). Medicine: Prof. Matthias Tschöp. Alexander von Humboldt Foundation. Prof. Matthias Tschöp, Chair of Metabolic Diseases, TUM School of Medicine
Asthma, bronchiectasis, and chronic obstructive pulmonary disease (COPD) that includes chronic bronchitis, and emphysema, are all obstructive lung diseases characterised by airway obstruction. This limits the amount of air that is able to enter alveoli because of constriction of the bronchial tree, due to inflammation. Obstructive lung diseases are often identified because of symptoms and diagnosed with pulmonary function tests such as spirometry. Many obstructive lung diseases are managed by avoiding triggers (such as dust mites or smoking), with symptom control such as bronchodilators, and with suppression of inflammation (such as through corticosteroids) in severe cases. A common cause of chronic bronchitis, and emphysema, is smoking; and common causes of bronchiectasis include severe infections and cystic fibrosis. The definitive cause of asthma is not yet known, but it has been linked to other atopic diseases. The breakdown of alveolar tissue, often as a result of tobacco-smoking leads to emphysema, which can become severe enough to develop into COPD. Elastase breaks down the elastin in the lung's connective tissue that can also result in emphysema. Elastase is inhibited by the acute-phase protein, alpha-1 antitrypsin, and when there is a deficiency in this, emphysema can develop. With persistent stress from smoking, the airway basal cells become disarranged and lose their regenerative ability needed to repair the epithelial barrier.
The causes are many and can be divided into conditions that have either true or perceived muscle weakness. True muscle weakness is a primary symptom of a variety of skeletal muscle diseases, including muscular dystrophy and inflammatory myopathy. It occurs in neuromuscular diseases, such as myasthenia gravis. Perceived muscle weakness occurs in diseases such as sleep disorders, and depression.
=== Education === Al-Fawzan enrolled in the public school in Ash-Shamasiyyah in 1950 (1369 AH). He completed his education at Al-Faysaliyyah School in Buraydah in 1952 (1371 AH), and was appointed as a primary school teacher. He then enrolled at the Ma'had Al-'Ilmī (The Institute of Knowledge) in Buraydah when it opened in 1954 (1373 AH), and graduated from it in 1958 (1377 AH). He joined the Kullīyat Ash-Sharīʿah (The College of Sharīʿah) in Riyadh and graduated in 1962 (1381 AH). Al-Fawzan later obtained a master’s degree in fiqh in the field of inheritance law, with a thesis titled: "Al-Taḥqīqāt Al-Marḍiyyah fī Al-Mabāḥith Al-Farḍiyyah" (A Satisfactory investigation into the issues of obligatory Shares in Inheritance). He subsequently obtained a doctorate in fiqh from the same college, with a dissertation titled: "Aḥkām Al-Aṭʿimah fī Al-Sharīʿah Al-Islāmiyyah" (The Rulings of Foods in the Islamic Sharīʿah).
Synthetic molecular motors are molecular machines capable of continuous directional rotation under an energy input. Although the term "molecular motor" has traditionally referred to a naturally occurring protein that induces motion (via protein dynamics), some groups also use the term when referring to non-biological, non-peptide synthetic motors. Many chemists are pursuing the synthesis of such molecular motors. The basic requirements for a synthetic motor are repetitive 360° motion, the consumption of energy and unidirectional rotation. The first two efforts in this direction, the chemically driven motor by Dr. T. Ross Kelly of Boston College with co-workers and the light-driven motor by Ben Feringa and co-workers, were published in 1999 in the same issue of Nature. As of 2020, the smallest atomically precise molecular machine has a rotor that consists of four atoms.
Sources: en.wikipedia.org
Mrs Justice Cheema-Grubb tells Alid: "The murder of Terence Carney was a terrorist act in which you hoped to influence the British government. You hoped to frighten the British people and undermine the freedoms they enjoy." The UK Health Security Agency confirms the number of cases of cryptosporidiosis in south Devon has risen to 46. Sir Paul McCartney has become the first billionaire British musician according to the 2024 Sunday Times Rich List. 18 May South West Water tells residents in most of Brixham, south Devon they no longer have to boil water before drinking it, but continues to advise households in upper Brixham, Hillhead and Kingswear to do so. The Met Office issues a weather warning for severe thunderstorms for Wales, south west England and the West Midlands. A number of people are reported to be isolating on the cruise ship MV Ventura with gastrointestinal symptoms. Technical problems result in customers being unable to use the M&S website and app for several hours. Declassified documents clear the Welsh Guards of any responsibility in the Argentinian Air Force bombing of RFA Sir Galahad on 8 June 1982, leading to the biggest loss of British lives during the Falklands War; some had blamed the Welsh Guards for disobeying orders to leave the ship, where 48 crewmen were killed. 19 May – South West Water apologises after 30 households in south Devon were wrongly told they could stop boiling water. 20 May The results of a public inquiry into the contaminated blood scandal are published.
== History == The Roman anatomist Galen commented on Hippocrates' work, classifying teeth as bones, noting their distinct characteristics compared to other bones. He was the first to discover nerves in teeth and identified seven cranial nerves in his research.
American kestrels feed largely on small animals such as grasshoppers, crickets, butterflies, moths, dragonflies, beetles, lizards, mice, voles, shrews, frogs, and small birds. The kestrel has also been reported to have killed scorpions, snakes, bats, and squirrels. The kestrel is able to maintain high population densities, at least in part because of the broad scope of its diet. The American kestrel's primary mode of hunting is by perching and waiting for prey to come near. The bird is characteristically seen along roadsides or fields perched on objects such as trees, overhead power lines, or fence posts. It also hunts by kiting, hovering in the air with rapid wing beats and scanning the ground for prey. Other hunting techniques include low flight over fields, or chasing insects and birds in the air. Prey is most often caught on the ground, though occasionally they take birds in flight. Before striking, the kestrel characteristically bobs its head and tail, then makes a direct flight toward the prey to grab it in its talons. Much like the red-tailed hawk, American kestrels conserve energy in a hunt and pick their attacks with care as to position and odds of success. During the breeding season, the bird will carry large prey back to its mate or young. One study found that an American kestrel pair "foraged in ways that minimized the costs of energy acquisition in its particular situation". For example, if the success rate for catching prey decreases significantly in a particular area, the bird will move to a different area.
A radioisotope thermoelectric generator (RTG, RITEG), or radioisotope power system (RPS), is a type of nuclear battery that uses an array of thermocouples to convert the heat released by the decay of a suitable radioactive material into electricity by the Seebeck effect. This type of generator has no moving parts and is ideal for deployment in remote and harsh environments for extended periods with no risk of parts wearing out or malfunctioning. RTGs are usually the most desirable power source for unmaintained situations that need a few hundred watts (or less) of power for durations too long for fuel cells, batteries, or generators to provide economically, and in places where solar cells are not practical. RTGs have been used as power sources in satellites, space probes, and uncrewed remote facilities such as a series of lighthouses built by the Soviet Union inside the Arctic Circle. Safe use of RTGs requires containment of the radioisotopes long after the productive life of the unit. The expense of RTGs tends to limit their use to niche applications in rare or special situations.
Sources: en.wikipedia.org
No. Epithalamin is a peptide-containing extract of bovine pineal glands, while epitalon is a single synthetic tetrapeptide. The extract contains many peptides and other tissue components, so its composition varies between batches in ways that a synthesised sequence does not.
It is not recognised as an endogenous peptide hormone. The four-residue sequence can appear inside larger proteins and in digestive fragments of dietary protein, but no dedicated pathway producing it as a signalling molecule has been identified.
Several cell-culture reports describe increased telomerase activity after treatment, measured by enzyme assays or by transcript levels. Results differ between cell types and laboratories, and measured telomere lengthening has been reported in some studies but not in others, which leaves the physiological relevance open.
It is a synthetic tetrapeptide built from alanine, glutamate, aspartate and glycine. The four residues are joined by standard peptide bonds, giving a linear chain rather than a branched structure.