A practical reference on AEDG: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2025-11-25. Anything still debated is marked as such rather than presented as settled.
Storage practice centres on limiting moisture, oxygen, and repeated temperature cycling. Freeze-dried powder is generally held desiccated at minus twenty degrees Celsius or colder and protected from light. Reconstituted solutions are markedly less stable, and the aspartate-glycine junction is prone to succinimide formation at neutral to mildly alkaline pH. Portioning material into single-use aliquots reduces degradation compared with repeated freeze-thaw cycles. Stability data specific to this tetrapeptide remain scarce, so most handling guidance is extrapolated from general peptide chemistry rather than measured directly.
Documentation accompanying research peptides usually includes a certificate of analysis listing the batch number, purity figure, and test methods applied. Buyers comparing suppliers should check whether the reported purity refers to chromatographic area or to a mass-balance calculation, because the two are not equivalent. Counter-ion content, residual solvents, and water content are sometimes omitted from such certificates even though they affect the actual peptide mass present. Independent verification through a second laboratory is the most direct way to confirm that a supplied material matches its label.
Purity assessment of peptide reagents normally relies on reversed-phase high-performance liquid chromatography. A gradient of acetonitrile in water with trifluoroacetic acid, paired with a C18 stationary phase, separates the target tetrapeptide from truncated sequences and deletion analogues. Detection at 214 nanometres exploits absorbance of the peptide backbone, since the molecule contains no aromatic residue. Results are expressed as a percentage of total peak area. Values above ninety-five percent are typical for research-grade material, although reporting conventions vary between suppliers.
Material supplied for laboratory use is normally a lyophilised white to off-white powder that dissolves readily in water and in isotonic saline. Lyophilised cakes are hygroscopic and should be equilibrated to room temperature before opening to limit condensation on the solid. Solutions are typically prepared at milligram-per-millilitre concentrations and divided into single-use aliquots, because repeated freeze–thaw cycles degrade short peptides. Aqueous solutions are far less stable than the dry powder, and identity is usually verified by mass spectrometry alongside purity estimation from reversed-phase high-performance liquid chromatography.
Epitalon is a synthetic linear tetrapeptide with the sequence alanine–glutamate–aspartate–glycine, abbreviated AEDG. Its molecular formula is C14H22N4O9 and the calculated mass is approximately 390.35 g/mol. The compound is made by solid-phase peptide synthesis rather than extracted from tissue, although early work described it as a short fragment of a peptide fraction obtained from bovine pineal extract. In the research literature the spelling epitalon and the variant epithalone both appear, while AEDG is the standard code used in peptide nomenclature.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Freeze-dried solid |
| Solubility class | Freely soluble in water | Aqueous buffers also suitable |
| Typical storage temperature | Minus 20 degrees Celsius or colder | Desiccated and light protected |
| Typical analytical method | RP-HPLC with UV detection | 214 nm on C18 column |
| Identity confirmation | Electrospray mass spectrometry | Sequence verified separately |
Identity is normally established by reversed-phase high-performance liquid chromatography combined with mass spectrometry, a pairing that separates components and confirms molecular mass at once. Purity is quoted as a percentage from the chromatogram, and figures above ninety-five percent are a frequent commercial specification. Amino acid analysis or sequencing supplies further confirmation when required. Because many short peptides behave similarly under chromatography, retention time alone does not establish sequence; the mass measurement is what separates one tetrapeptide from another, and certificates should report both.
Short peptides such as AEDG are normally supplied as a freeze-dried solid and are kept dry, cold, and shielded from light. Holding at minus twenty degrees Celsius is common for the long term, while a refrigerator suffices for brief periods before use. The material takes up moisture to some degree, so containers should stay sealed and be allowed to reach room temperature before opening, which limits condensation on the contents. Repeated warming and cooling of a single container is discouraged because it admits water and can lower the amount of intact peptide.
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.
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.
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.
== Further reading == Fruton, Joseph S. Proteins, Enzymes, Genes: The Interplay of Chemistry and Biology. Yale University Press: New Haven, 1999. ISBN 0-300-07608-8 Kohler, Robert. From Medical Chemistry to Biochemistry: The Making of a Biomedical Discipline. Cambridge University Press, 1982.
== Drug interactions == Loperamide is a substrate of P-glycoprotein; therefore, the concentration of loperamide increases when given with a P-glycoprotein inhibitor. Common P-glycoprotein inhibitors include quinidine, ritonavir, and ketoconazole. Loperamide can decrease the absorption of some other drugs. As an example, saquinavir concentrations can decrease by half when given with loperamide. Loperamide is an antidiarrheal agent, which decreases intestinal movement. As such, when combined with other antimotility drugs, the risk of constipation is increased. These drugs include other opioids, antihistamines, antipsychotics, and anticholinergics.
The new regime was intended to be transitory, but gradually closed in on itself and became a full dictatorship with the promulgation of the Fifth Institutional Act in 1968. Oppression was not limited to those who resorted to guerrilla tactics to fight the regime, but also reached institutional opponents, artists, journalists and other members of civil society, inside and outside the country through "Operation Condor". Like other authoritarian regimes, due to an economic boom, known as the "economic miracle", the Brazilian military dictatorship reached a peak in popularity in the early 1970s. Slowly, however, the wear and tear of years of dictatorial power had not slowed the repression, even after the defeat of the leftist guerrillas. The inability to deal with the economic crises of the period and popular pressure made a redemocratization policy inevitable, which from the regime side was led by Generals Ernesto Geisel and Golbery do Couto e Silva. With the enactment of the Amnesty Law in 1979, Brazil began a slow return to democracy, which was completed during the 1980s.
== Oxford == Oxford University Press, which publishes the Oxford English Dictionary and many other dictionaries, announces an Oxford Dictionaries UK Word of the Year and an Oxford Dictionaries US Word of the Year; sometimes these are the same word and simply dubbed Word of the Year. The word need not have been coined within the year or twelve months but it does need to have become prominent or notable during that time. There is no guarantee that the Word of the Year will be included in any Oxford dictionary if it's not present. The Oxford Dictionaries Words of the Year are selected by editorial staff from each of the Oxford dictionaries. The selection team is made up of lexicographers and consultants to the dictionary team, and editorial, marketing, and publicity staff.
=== Nickel exposure === Nickel is both naturally abundant – it is the fifth most common element on earth – and widely used in industry and commercial goods. Workplace nickel exposure is common in many industries, and the performance of normal work tasks can result in nickel skin levels sufficient to elicit dermatitis. Within the workplace, individuals may be exposed to significant amounts of nickel, airborne from the combustion of fossil fuels or from contact with tools that are nickel plated. Historically, workplaces where prolonged contact with soluble nickel has been high have shown high risks for allergic contact nickel dermatitis. For example, nickel dermatitis was common in the past among nickel platers. Outbreaks of nickel allergy from consumer goods have been documented throughout the 20th century, with jewelry, stocking suspenders, and metallic buttons on blue jeans each resulting in dermatitis at the point of contact. Nickel can also be present in food and drinking water; ingestion of increased nickel is not associated with systemic allergic disease, but is associated with flare-ups of dermatitis or aggravation of vesicular hand eczema. Similarly, aggravation of dermatitis has been reported in response to nickel-containing surgical implants or dental gear. The risk of an object eliciting nickel allergy is linked to the amount of nickel released by its surface (and not to its total nickel content). Suspected objects can be screened by wiping the surface with a 1% dimethylglyoxime solution that turns pink if more than 0.5 μg/cm2 per week is released by the surface.
Sources: en.wikipedia.org
In late 2025, a former senior officer told the inquiry that British forces in Afghanistan executed suspects as well as unarmed civilians, including children, during operations and nothing was done despite widespread knowledge about the activities. On 1 December 2025, the officer, known as N1466, at the time the Assistant Chief of Staff for Operations in the UK Special Forces Headquarters, said that during a raid, SAS operatives shot at a mosquito net until there was no movement. He stated, "When the net was uncovered it was women and children. The incident was covered up and the individual who did the shooting was given some form of award to make it look legitimate." N1466 also confirmed that evidence supporting allegations of war crimes was not passed to military police. In May 2026, the inquiry published a summary of the account of a former chief of staff, known as N2252. The officer explained to the inquiry in 2024 that the reason for the lack of referral – breaching every British military officer's "legal obligation to alert military police if they become aware that someone under their command may have committed a war crime" – was because it was believed that an investigation could disrupt operations and damage morale. An additional factor was that some of the evidence had originated from a rival special forces regiment.
== Further reading == Glutathione synthetase deficiency at NLM Genetics Home Reference Beutler, E; Gelbart, T; Pegelow, C (1986). "Erythrocyte glutathione synthetase deficiency leads not only to glutathione but also to glutathione-S-transferase deficiency". Journal of Clinical Investigation. 77 (1): 38–41. doi:10.1172/JCI112298. PMC 423305. PMID 3944259.
== Veterinary use == Ivermectin is routinely used to control parasitic worms in the gastrointestinal tract of ruminant animals. These parasites normally enter the animal when it is grazing, pass the bowel, and set and mature in the intestines, after which they produce eggs that leave the animal via its droppings and can infest new pastures. Ivermectin is only effective in killing some of these parasites, because of an increase in anthelmintic resistance. This resistance has arisen from the persistent use of the same anthelmintic drugs for the past 40 years. Resistance to ivermectin has also been reported in cattle tick (Rhipicephalus microplus) populations from the Brazilian Amazon, including resistant populations identified in western Pará. Additionally, the use of Ivermectin for livestock has a profound impact on dung beetles, such as T. lusitanicus, as it can lead to acute toxicity within these insects. In dogs, ivermectin is routinely used as prophylaxis against heartworm. Dogs with defects in the P-glycoprotein gene (MDR1), often collie-like herding dogs, can be severely poisoned by ivermectin. The mnemonic "white feet, don't treat" refers to Scotch collies that are vulnerable to ivermectin. Some other dog breeds (especially the Rough Collie, the Smooth Collie, the Shetland Sheepdog, and the Australian Shepherd), also have a high incidence of mutation within the MDR1 gene (coding for P-glycoprotein) and are sensitive to the toxic effects of ivermectin. For dogs, the insecticide spinosad may have the effect of increasing the toxicity of ivermectin.
At the same time, the need for such a system was becoming increasingly pressing. In 1932, Winston Churchill and his friend, confidant and scientific advisor Frederick Lindemann travelled by car in Europe, where they saw the rapid rebuilding of the German aircraft industry. It was in November of that year that Stanley Baldwin gave his famous speech, stating that "The bomber will always get through". In the early summer of 1934, the RAF carried out large-scale exercises with up to 350 aircraft. The forces were split, with bombers attempting to attack London, while fighters, guided by the Observer Corps, attempted to stop them. The results were dismal. In most cases, the vast majority of the bombers reached their target without ever seeing a fighter. To address the one-sided results, the RAF gave increasingly accurate information to the defenders, eventually telling the observers where and when the attacks would be taking place. Even then, 70 per cent of the bombers reached their targets unhindered. The numbers suggested any targets in the city would be destroyed. Squadron Leader P. R. Burchall summed up the results by noting that "a feeling of defencelessness and dismay, or at all events of uneasiness, has seized the public." In November, Churchill gave a speech on "The threat of Nazi Germany" in which he pointed out that the Royal Navy could not protect Britain from an enemy who attacked by air. Through the early 1930s, a debate raged within British military and political circles about strategic airpower.
All our advice to the commander in chief [went] through the chief of our section, who was a career civil servant. His guiding principle was to tell the commander in chief things that the commander in chief liked to hear... To push the idea of ripping out gun turrets, against the official mythology of the gallant gunner defending his crew mates... was not the kind of suggestion the commander in chief liked to hear. On hearing the news of the bombing of Hiroshima:
Sources: en.wikipedia.org
Reversed-phase high-performance liquid chromatography with ultraviolet detection at 214 nanometres is the usual approach. Peak area percentage provides a purity figure relative to other components in the sample. Mass spectrometry is then applied to confirm identity.
Aspartate can cyclise into a succinimide intermediate that later hydrolyses back as isoaspartate. Both forms share the same molecular mass, so mass spectrometry alone cannot tell them apart. This shapes how purity data should be interpreted.
Freeze-dried material is normally kept desiccated below minus twenty degrees Celsius and shielded from light. Solutions are prepared shortly before use and held cold. Repeated thawing is avoided because it accelerates aggregation and degradation.
It is a synthetic tetrapeptide. Its sequence was derived from research on peptide fractions of bovine pineal extract, and the intact AEDG sequence has not been demonstrated as an abundant free peptide in human tissue.