If you have been reading about Khavinson and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2026-08-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
| 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.
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.
Material sold for research use varies widely in documented quality. A useful verification package includes a certificate of analysis that states peptide content rather than only net weight, the chromatographic method and column used, and a mass spectrum consistent with the expected mass. Independent testing by a third-party laboratory is occasionally reported. Statements of identity resting only on a supplier label provide little assurance, and the gap between nominal mass and actual peptide content can be substantial once counterions and residual water are counted.
Peptides of this size are generally stable as dry solids but degrade in solution over time. The principal routes are hydrolysis of the peptide backbone and oxidation, with hydrolysis favoured by elevated temperature and extreme pH. Aqueous solutions held at room temperature can show measurable loss of purity within days, while frozen aliquots are considerably more durable. Because the sequence contains neither cysteine nor methionine, oxidation is less of a concern than for many other peptides, but pH control during handling still matters.
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.
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.
== External links == The MEROPS online database for peptidases and their inhibitors: A01.007[link removed] Renin at the U.S. National Library of Medicine Medical Subject Headings (MeSH) Overview of all the structural information available in the PDB for UniProt: P00797 (Renin) at the PDBe-KB.
On the basis of these studies, as well as problems with allergies and clothing discoloration, PABA fell out of favor as a sunscreen. In 2008 it was banned as a sunscreen ingredient in the European Union and in 2019 the FDA proposed its limited use. However, water-insoluble PABA derivatives such as padimate O are currently used in some cosmetic products including mascara, concealer, and matte lipsticks. As of 2008, the advancement of new sunscreen is focused on developing a broad spectrum of active ingredients that provide consistent protection across all wavelengths, including UVA. Researchers are considering the PABA–TiO2 Hybrid Nanostructures that result from the method of aqueous in situ synthesis with PABA and TiO2.
=== 1950 === January 5: The UK recognizes the People's Republic of China. The Republic of China severs diplomatic relations with the United Kingdom. January 13: Because of the failure to replace Taiwan with the People's Republic of China in the United Nations Security Council the Soviet Union boycotts the United Nations by having their diplomat Yakov Malik not attend any United Nations Security Council meetings. January 18: China officially recognizes the Democratic Republic of Vietnam. January 21: The last Kuomintang soldiers surrender on continental China. January 31: President Truman announces the beginning of the development of a hydrogen bomb. February 3: Soviet Union establishes diplomatic relations with Indonesia through an exchange of telegrams between Indonesian Vice-president, Mohammad Hatta and Soviet Foreign Minister Andrey Vyshinsky. February 7: The UK and the US recognize the State of Vietnam. February 9: Senator Joseph McCarthy first claims without evidence that Communists have infiltrated the U.S. State Department, leading to a controversial series of anti-Communist investigations in the United States. February 12: The Soviet Union and the People's Republic of China sign a pact of mutual defense. March 11: Kuomintang leader Chiang Kai-shek moves his capital to Taipei, Taiwan, establishing a stand-off with the People's Republic of China. April 7: United States State Department Director of Policy Planning Paul Nitze issues NSC 68, a classified report, arguing for the adoption of containment as the cornerstone of United States foreign policy.
Moreover, one of the requirements includes the potential sperm donor to be able to live nearby the sperm bank in order to provide samples once to twice a month for at least a term of six months. Some controversy stems from the fact that donors father children for others, in the majority of cases, for single people or same-sex couples, but usually take no part in the upbringing of such children. The issue of sperm banks providing fertility services to single women and coupled lesbians so that they can have their own biological children by a donor is itself often controversial in some jurisdictions, but in many countries where sperm banks operate, this group form the main body of recipients. Donors usually do not have a say in who may be a recipient of their sperm. Another controversy centers around the use of sperm posthumously, or after the death of the sperm donor, as pioneered by California Cryobank. Within the United States, there were differences when it came to a child conceived after the father's death and the eligibility for survivor's benefits. Under California law, there was one court case (Vernoff vs. Astrue) in which the mother's child (conceived after the father's death) was not eligible for the survivor's benefits. However, Arizona courts had a different approach when it came to children who were born after a father's death, holding that the children were eligible for the survivors benefits. There have been numerous other stories of similar situations across different states in the United States and even the United Kingdom.
Sources: en.wikipedia.org
== Personal life == Liebling has made dubious claims that he turned to drug dealing during the 1970s, smuggling substances for the Medellin Cartel through Virginia and Colombia during the height of the Pablo Escobar era. He went as far as to claim he earned "tens of millions - sometimes in cash" during this period, but "blew it all, every dime of it on [his] own personal whoring, car-buying, house-buying for [his] friends, buying Ferraris and chinchilla coats and diamond rings for broads and flaunting it." In the 1980s, Liebling was in a relationship with Cheri Blade, a member of the band Chained Lace, with whom Pentagram often toured. He married Hallie Liebling on November 25, 2009. The couple welcomed their son, Robert Joseph Liebling, in 2010, when Hallie was 24 years old. They have been separated since around 2013.
=== From specimen collection === Most causes of in vitro hemolysis are related to specimen collection. Difficult collections, unsecure line connections, contamination, and incorrect needle size, as well as improper tube mixing and incorrectly filled tubes are all frequent causes of hemolysis. In vitro hemolysis during specimen collection can cause inaccurate laboratory test results by contaminating the surrounding plasma with the contents of hemolyzed red blood cells. For example, the concentration of potassium inside red blood cells is much higher than in the plasma and so an elevated potassium level is usually found in biochemistry tests of hemolyzed blood. After the blood collection process, in vitro hemolysis can still occur in a sample due to external factors, such as prolonged storage, incorrect storage conditions and excessive physical forces by dropping or vigorously mixing the tube.
== Early life == Chain was born in Wilmington, Delaware, attended high school at Fork Union Military Academy and was a member of Fork Union Chapter of DeMolay International. He earned a Bachelor of Arts degree in history in 1956 and was awarded an honorary doctorate in humane letters in 1990, both from Denison University. While at Denison University, General Chain was a member of the Sigma Alpha Epsilon fraternity. In 1971 he graduated from the National War College and concurrently earned a master's degree in international affairs from George Washington University.
The density of francium is expected to be around 2.48 g/cm3 (Mendeleev's method extrapolates 2.4 g/cm3). Another calculation gives a much higher value of 3.57 g/cm3. Francium is predicted to have a bulk modulus of 2.1–2.6 GPa. Linus Pauling estimated the electronegativity of francium at 0.7 on the Pauling scale, the same as caesium; the value for caesium has since been refined to 0.79, but there are no experimental data to allow a refinement of the value for francium. Francium has a slightly higher ionization energy than caesium, 392.811(4) kJ/mol as opposed to 375.7041(2) kJ/mol for caesium, as would be expected from relativistic effects, and this would imply that caesium is the less electronegative of the two. Francium should also have a higher electron affinity than caesium and the Fr− ion should be more polarizable than the Cs− ion.
=== Research === G-CSF when given early after exposure to radiation may improve white blood cell counts, and is stockpiled for use in radiation incidents. Mesoblast planned in 2004 to use G-CSF to treat heart degeneration by injecting it into the blood-stream, plus SDF (stromal cell-derived factor) directly to the heart. G-CSF has been shown to reduce inflammation, reduce amyloid beta burden, and reverse cognitive impairment in a mouse model of Alzheimer's disease. Due to its neuroprotective properties, G-CSF is currently under investigation for cerebral ischemia in a clinical phase IIb and several clinical pilot studies are published for other neurological disease such as amyotrophic lateral sclerosis A combination of human G-CSF and cord blood cells has been shown to reduce impairment from chronic traumatic brain injury in rats.
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.
Vladimir Khavinson and colleagues at research institutes in Saint Petersburg developed and studied the peptide. Their program examined short peptides as regulators of aging and neuroendocrine function. Epitalon was one of several compounds produced by that group.