AEDG comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Updated 2026-06-27. Numbers and descriptions here follow the published literature rather than marketing material.
The compound is described in the literature as a derivative of epithalamin, a preparation obtained from bovine pineal tissue. Work on this peptide family was carried out mainly by a research group in Saint Petersburg beginning in the 1980s, and the substance was later registered for clinical use in Russia under the name Epitalon. Outside that region it is generally treated as a research chemical rather than an approved medicine. Statements about its biological activity rest on a relatively small number of studies, and independent replication remains limited.
In its supplied form epitalon is a white to off-white powder, usually lyophilized and often hygroscopic. It dissolves readily in water and in aqueous buffers, and it is commonly handled as the acetate or trifluoroacetate salt to improve stability during purification and drying. The amide backbone is labile in aqueous media, so solutions are less durable than the dry solid. Handling notes in the chemical literature therefore emphasize keeping the powder dry, cool and shielded from light until it is dissolved.
Epitalon is a synthetic tetrapeptide whose sequence is alanine-glutamate-aspartate-glycine, written in single-letter code as AEDG. The four residues are joined by three peptide bonds, giving a linear backbone with no branching and no disulfide bridges. Its calculated molecular mass for the free form is approximately 390.3 daltons, a figure that rises when the compound is supplied as an acetate or trifluoroacetate salt. Because the chain is short, the molecule is defined entirely by its residue order rather than by any folded three-dimensional structure.
Regulatory treatment differs by country. No formulation of epitalon holds a marketing authorisation as a medicine in the United States or the European Union, where material sold for laboratory use is handled as a research chemical and is not intended for human consumption. In Russia, several short peptide preparations from the same institute's peptide series are registered medicinal products, and epitalon appears in that national context. Elsewhere it is frequently offered as a cosmetic ingredient, a category with lighter requirements. Advertising claims about longevity or disease prevention are restricted in most jurisdictions, which limits how sellers describe the compound.
Freeze-dried epitalon is normally kept at minus twenty degrees Celsius in a sealed, desiccated container, protected from light. Short excursions at ambient temperature during shipping are generally tolerated, but repeated warming and cooling cycles encourage moisture uptake, which shortens shelf life. Once dissolved, the peptide is far less stable than the solid: aqueous solutions are subject to hydrolysis and to deamidation at the aspartate and glutamate residues. Working solutions are therefore held refrigerated and used within days, and repeated freezing and thawing of the same vial is best avoided.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic tetrapeptide | Four residues, linear chain |
| Residue sequence | Ala-Glu-Asp-Gly | Single-letter form AEDG |
| Calculated mass | 390.3 daltons | Value for the free, uncharged form |
| Appearance | White to off-white powder | Usually supplied lyophilized |
| Solubility | Freely soluble in water | Often handled as a salt form |
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.
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.
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.
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.
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.
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.
Dissolution is usually performed in water or a suitable aqueous buffer, and the resulting liquid is divided into single-use portions before freezing. Freeze-thaw cycling is a recognised source of loss for short peptides, since each cycle can encourage aggregation or adsorption onto container walls. Working solutions are generally kept cold and used within a short window, although published stability data specific to epitalon are thin. Containers should be marked with concentration and date, and solutions examined for cloudiness before use.
When reporting on the masses of extrasolar planets, astronomers often discuss them in terms of multiples of Jupiter's mass (MJ = 1.9 ×1027 kg). For example, "Astronomers recently discovered a planet outside our Solar System with a mass of approximately 3 Jupiters." Furthermore, the mass of Jupiter is nearly equal to one thousandth of the mass of the Sun.
==== Males ==== In the past, early onset of puberty in males has been associated with positive outcomes, such as leadership in high school and success in adulthood. However, recent studies have revealed that the risks and problems of early maturation in males might outweigh the benefits. Early-maturing males develop "more aggressive, law-breaking, and alcohol abusing" behaviors, which result in anger towards parents and trouble in school and with the police. Early puberty also correlates with increased sexual activity and a higher instance of teenage pregnancy, both of which can lead to depression and other psychosocial issues. On the other hand, late-maturing males develop lower self-esteem and confidence and generally have lower popularity among peers, due to their less-developed physiques. Also, they experience problems with anxiety and depression and are more likely to be afraid of sex than other males.
Deamination is the removal of an amino group from a molecule. Enzymes that catalyse this reaction are called deaminases. In the human body, deamination takes place primarily in the liver; however, it can also occur in the kidney. In situations of excess protein intake, deamination is used to break down amino acids for energy. The amino group is removed from the amino acid and converted to ammonia. The rest of the amino acid is made up of mostly carbon and hydrogen, and is recycled or oxidized for energy. Ammonia is toxic to the human system, and enzymes convert it to urea or uric acid by addition of carbon dioxide molecules (which is not considered a deamination process) in the urea cycle, which also takes place in the liver. Urea and uric acid can safely diffuse into the blood and then be excreted in urine.
This inhibition can lead to a depletion of dopamine and norepinepherine in the brain due to the lack of the precursor L-DOPA (L-3,4-dyhydroxyphenylalanine) which is synthesized by tyrosine hydroxylase. This drug is rarely used and can cause depression, but it is useful in treating pheochromocytoma and also resistant hypertension. Older examples of inhibitors mentioned in the literature include oudenone and aquayamycin.
In late 2008, Valve released lifetime retail sales figures as part of a company profile in Game Informer magazine. The two main Half-Life games had sold 15.8 million units at retail (9.3 million for the first, 6.5 million for the second), while the Half-Life expansions had sold 1.9 million (Opposing Force: 1.1 million, Blue Shift: 800,000) and Half-Life 2 expansions 1.4 million units (all for Episode One) by the end of November 2008. Additionally, The Orange Box, which included Half-Life 2 and both of its episodic expansions, sold 3 million units at retail by November 2008. This put franchise sales at around 18.8 million full games (Half-Life: 9.3m, Half-Life 2: 6.5m) and approximately 6.3 million expansions (Opposing Force: 1.1m, Blue Shift: 0.8m, Episode One: 1.4m, Episode 2: 3.0m) at the same month. These figures did not account for digital sales. Half-Life: Counter-Strike sold 4.2 million units standalone by the same time, while its remake, Counter-Strike: Source was bundled with every sold retail copy of Half-Life 2. Forbes reported that, including digital sales, Half-Life 2 had sold over 12 million copies by February 2011.
Sources: en.wikipedia.org
This same study shows more inaccurate statements from the models when they advocate for candidates of the political right. AI researchers at Microsoft, OpenAI, universities and other organisations have suggested using "personhood credentials" as a way to overcome online deception enabled by AI models.
==== Monofloral ==== Monofloral honey is made primarily from the nectar of one type of flower. Monofloral honeys have distinctive flavors and colors because of differences between their principal nectar sources. To produce monofloral honey, beekeepers keep beehives in an area where the bees have access, as far as possible, to only one type of flower. In practice, a small proportion of any monofloral honey will be from other flower types. Typical examples of North American monofloral honeys are clover, orange blossom, sage, tupelo, buckwheat, fireweed, mesquite, sourwood, cherry, and blueberry. Some typical European examples include thyme, thistle, heather, acacia, dandelion, sunflower, lavender, honeysuckle, and varieties from lime and chestnut trees. In North Africa (e.g. Egypt), examples include clover, cotton, and citrus (mainly orange blossoms). The unique flora of Australia yields a number of distinctive honeys, with some of the most popular being yellow box, blue gum, ironbark, bush mallee, Tasmanian leatherwood, and macadamia. Mānuka honey, produced from the nectar of Leptospermum scoparium in New Zealand and parts of Australia, is darker in color and has an earthy, slightly bitter flavor profile compared with lighter honeys such as clover.
Semen is typically translucent with white, grey or even yellowish tint, with a viscous consistency similar to that of egg whites. Blood in the semen can cause a pink or reddish colour, known as hematospermia, and may indicate a medical problem which should be evaluated by a doctor if the symptom persists. After ejaculation, the latter part of the ejaculated semen coagulates immediately, forming globules, while the earlier part of the ejaculate typically does not. After a period typically ranging from 15 to 30 minutes, prostate-specific antigen present in the semen causes the decoagulation of the seminal coagulum. It is postulated that the initial clotting helps keep the semen in the vagina, while liquefaction frees the sperm to make their journey to the ova. A 2005 review found that the average reported viscosity of human semen in the literature was 3–7 centipoises (cP), or, equivalently, millipascal-seconds (mPa·s).
== Synthesis == After the biotech company Genentech discovered and patented the gene for BST in the 1970s, it became possible to synthesize the hormone using recombinant DNA technology to create recombinant bovine somatotropin (rBST), recombinant bovine growth hormone (rBGH), or artificial growth hormone.
Sources: en.wikipedia.org
The peptide contains four residues in the order alanine, glutamate, aspartate and glycine, abbreviated AEDG. The chain is linear and held together by three peptide bonds. Its calculated mass for the uncharged free form is about 390.3 daltons.
Epithalamin refers to a crude preparation derived from bovine pineal tissue, which contains many components. Epitalon is a single synthetic tetrapeptide identified from that material and produced by chemical synthesis. The two names are sometimes confused because early reports treated the synthetic peptide as an active fragment of the extract.
It has been registered for clinical use in Russia, where it is associated with a small family of short peptides. In most other jurisdictions it is not an approved medicine and is traded as a research chemical. Regulatory status varies by country and changes over time.
The solid is kept cold, dry and dark, typically at minus twenty degrees Celsius, in a sealed container with desiccant. Dissolved material is kept refrigerated and used promptly. Freezing and thawing a solution repeatedly is avoided because it accelerates degradation.