Khavinson 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.
Last reviewed on 2026-08-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
（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.
Chemically, the molecule consists of four amino acid residues joined by three peptide bonds, with a free N-terminal amino group and a free C-terminal carboxyl group. Its molecular formula is C14H22N4O9, and its monoisotopic mass is approximately 390 daltons. The acidic glutamate and aspartate side chains give the peptide a net negative charge near neutral pH, a property that shapes its chromatographic behaviour and solubility profile. No disulfide bridges or other post-translational modifications are present, so the primary sequence alone defines the structure.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Linear tetrapeptide | Four residues joined by three peptide bonds |
| Sequence | Ala-Glu-Asp-Gly | Commonly abbreviated AEDG |
| Molecular formula | C14H22N4O9 | Free acid form |
| Monoisotopic mass | Approximately 390 Da | Matches values reported from mass spectrometry |
| Net charge near neutral pH | Negative | Contributed by glutamate and aspartate side chains |
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.
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.
The proposed relationship between epitalon and pineal function is a central part of its background. Khavinson's group reported that short peptides corresponding to regions of larger pineal proteins could influence gene expression in cells. Epitalon was framed as a synthetic analogue of an active fragment rather than a direct isolation product. Whether the tetrapeptide reproduces the effects of the parent extract is an open question, because comparative studies are limited and the parent extract itself is not a single defined substance.
Interest in epitalon is usually discussed within the broader field of short peptide bioregulators, a category that includes other synthetic di-, tri-, and tetrapeptides studied by the same research group. These compounds share a common rationale: that small fragments of tissue-derived proteins can retain biological activity and can be produced reproducibly. The category as a whole remains outside mainstream pharmacological consensus, and epitalon specifically has a limited presence in independent, non-Russian research literature, which shapes how its evidence base is described.
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 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.
=== Ultrasonication-assisted spray ionization === Ultrasonication-assisted spray ionization (UASI) is similar to the above techniques but uses an ultrasonic transducer to achieve atomization of the material and generate ions.
Topical hydrocortisone is a drug under the class of corticosteroids, which is used for the treatment of skin inflammation, itchiness and allergies. Some examples include insect bites, dermatitis and rash. Hydrocortisone was discovered by Nobel laureates Edward C. Kendall and Philip S. Hench in the 1930s while they were conducting research on rheumatoid arthritis. Its topical use was first recorded in the 1950s. The most common adverse effects after the application of topical hydrocortisone are burning and stinging sensations. Side effects after long-term usage include eyesight damage, elevated blood sugar levels and adrenal gland disorders. Topical hydrocortisone is available in several dosage forms such as solution, lotion, cream, ointment and spray. Some brand names for topical hydrocortisone include Anusol HC, Cortizone 10, and Synacort.
== Prognosis == Challenges presented to people affected by this condition include: psychologically coming to terms with the condition, difficulties with sexual function, infertility. Long-term studies indicate that with appropriate medical and psychological treatment, those with CAIS can be satisfied with their sexual function and psychosexual development. Individuals with this condition can lead active lives and expect a normal lifespan.
Sources: en.wikipedia.org
3 WBr5 + Al thermal gradient→475 °C → 240 °C 3 WBr4 + AlBr3 2 EuBr3 + H2 → 2 EuBr2 + 2 HBr 2 TaBr4 500 °C→ TaBr3 + TaBr5 Most metal bromides with the metal in low oxidation states (+1 to +3) are ionic. Nonmetals tend to form covalent molecular bromides, as do metals in high oxidation states from +3 and above. Both ionic and covalent bromides are known for metals in oxidation state +3 (e.g. scandium bromide is mostly ionic, but aluminium bromide is not). Silver bromide is very insoluble in water and is thus often used as a qualitative test for bromine.
=== Support selection === For a support material to be ideal, it must be hydrophilic, inert towards enzymes, biocompatible, microbial attack and compression resistant, and must be affordable. Support materials can be organic or inorganic, synthetic or natural (depending on the composition), since they are biomaterial types at the end. There is no universal type of a support material to be used for the immobilization of all enzymes. However, there are some commonly used supports such as silica-based carriers, acrylic resins, synthetic polymers, active membranes and exchange resins. One of the hardest processes before the immobilization process itself, is the selection of support material since it relies on the enzyme type, reaction of media, safety policy of hydrodynamic and reaction conditions. As different types of support give different physical and chemical characteristics and properties, which would effect enzyme function, such as: Hydrophilicity/hydrophobicity, surface chemistry, and pore size.
=== Example values === Values for log Kow typically range between -3 (very hydrophilic) and +10 (extremely lipophilic/hydrophobic). The values listed here are sorted by the partition coefficient. Acetamide is hydrophilic, and 2,2′,4,4′,5-Pentachlorobiphenyl is lipophilic.
Sources: en.wikipedia.org
==== In foals ==== Investigators from Brazil used foals in an attempt to quantify the pain of freeze branding compared to hot branding. Two groups of foals were fitted with heart monitors and randomly assigned either freeze branding or hot branding. Blood samples were taken 30 minutes before branding and then again, 30 and 60 minutes after branding. Hot brands were applied for 3 seconds or less and liquid nitrogen-chilled freeze brands were applied for 60 seconds (sic). The foals were video-recorded during their branding for later ethological analysis by two veterinarians. These experts in horse body language scrutinized the recordings and assigned scores based on how many indications of pain each foal exhibited during branding. The score ranged from 0 to 6 and attempted to quantify the distress, if any, shown by the foals. Cortisol levels were determined from the three blood samples and heart rates were recorded until 60 minutes after branding. No sham-branded control group was used. Their analysis of collected data indicated that "both hot and freeze iron branding induced stress responses in foals, with a similar increase in the cortisol levels and intense pain and escape behavioral response" but that freeze branding resulted in less autonomic (fight-or-flight) response, suggesting that hot branding was the more stressful of the two procedures. This, combined with the lesser severity of wounds created by the freeze brands led the experimenters to conclude that freeze branding was the better choice. The results led the authors to recommend the prohibition of hot branding.
== Medical Relevance == Historically, the focus of many insulin related metabolic diseases has focused on mature insulin. However, in recent years the importance of studying the structure and function of proinsulin or proinsulin:insulin ratio in relation to these diseases has become increasingly clear.
=== Synthesis === Progesterone is commercially produced by semisynthesis. Two main routes are used: one from yam diosgenin first pioneered by Marker in 1940, and one based on soy phytosterols scaled up in the 1970s. Additional (not necessarily economical) semisyntheses of progesterone have also been reported starting from a variety of steroids. For the example, cortisone can be simultaneously deoxygenated at the C-17 and C-21 position by treatment with iodotrimethylsilane in chloroform to produce 11-keto-progesterone (ketogestin), which in turn can be reduced at position-11 to yield progesterone.
Sources: en.wikipedia.org
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.
The compound came out of work on epithalamin, a peptide preparation derived from pineal tissue, conducted largely in Russian laboratories. Later studies in other countries examined it mainly in cell cultures and animal models.
The tetrapeptide sequence is a synthetic construct rather than a described circulating peptide. It was derived by analogy to peptide fractions obtained from tissue extracts, not isolated from blood or tissue as such.
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.