This is a working overview of succinimide formation, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-05-08 and is reviewed periodically as new material appears.
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.
Several names circulate for the same molecule, including epitalon, epithalone, epithalamin tetrapeptide, and the sequence code AEDG. A CAS registry number, 307297-39-8, is commonly cited for it, though catalogue entries should be checked against supplier documentation because mislabelled records occur. In its usual form the peptide carries free amino and carboxyl termini and is neither glycosylated nor lipidated. Researchers distinguish the defined tetrapeptide from epithalamin itself, a crude pineal preparation containing many peptides that is not chemically characterised.
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 |
|---|---|---|
| Peptide sequence | Ala-Glu-Asp-Gly | Single-letter form AEDG |
| Compound class | Synthetic tetrapeptide | Not a natural free peptide |
| Research origin | Russian gerontology institutes | Developed during the 1990s |
| Main research claim | Telomerase activation | Evidence mainly from cultured cells |
| Regulatory status | Not an approved drug | Handled as a research material |
Laboratory handling begins with dissolution of the lyophilized powder in water or a suitable aqueous buffer. The dry solid is the more stable form, so stock solutions are generally prepared only when required and kept cold afterwards. Repeated freezing and thawing of a solution is avoided because it encourages aggregation and gradual loss of the intact chain. Diluents and containers are selected to limit adsorption of a short peptide onto plastic surfaces and to reduce microbial growth in aqueous preparations.
Stability depends strongly on pH, temperature and the presence of oxygen and trace metals. Cleavage of the backbone proceeds faster under neutral to alkaline conditions, whereas acidic solutions tend to slow that reaction. The aspartate and glutamate side chains can undergo deamidation or imide formation over time, generating closely related impurities. Published stability data specific to epitalon are sparse, so the usable life of a given solution is best regarded as an open question that depends on buffer composition, concentration and storage temperature.
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.
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.
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.
Identity confirmation uses mass spectrometry, usually electrospray ionisation in positive mode or matrix-assisted laser desorption. The protonated free peptide produces a signal near three hundred and ninety-one daltons, while salt adducts shift that value slightly. Tandem mass spectrometry or amino acid analysis supplies sequence-level confirmation, which a single mass measurement cannot. Peptides containing aspartate can cyclise into succinimide intermediates that hydrolyse to isoaspartate isomers of identical mass. Because those isomers are difficult to separate chromatographically, identity and purity results carry more weight when interpreted together.
Additional evidence supporting the concept of an RNA world has resulted from research on viroids, the first representatives of a novel domain of "subviral pathogens". Viroids infect plants, where most are pathogens, and consist of short stretches of highly complementary, circular, single-stranded and non-coding RNA without a protein coat. They are extremely small, ranging from 246 to 467 nucleobases, compared to the smallest known viruses capable of causing an infection, with genomes about 2,000 nucleobases in length. Based on their characteristic properties, in 1989 plant biologist Theodor Diener argued that viroids are more plausible living relics of the RNA world than introns and other RNAs considered candidates at the time. Diener's hypothesis would be expanded by the research group of Ricardo Flores, and gained a broader audience when in 2014, a New York Times science writer published a popularized version of the proposal. The characteristics of viroids highlighted as consistent with an RNA world were their small size, high guanine and cytosine content, circular structure, structural periodicity, the lack of protein-coding ability and, in some cases, ribozyme-mediated replication. One aspect critics of the hypothesis have focused on is that the exclusive hosts of all known viroids, angiosperms, did not evolve until billions of years after the RNA world was replaced, making viroids more likely to have arisen through later evolutionary mechanisms unrelated to the RNA world than to have survived via a cryptic host over that extended period.
The systematic names and formulas given refer to hypothetical forms in which amino groups are unprotonated and carboxyl groups are undissociated. This convention is useful to avoid various nomenclatural problems but should not be taken to imply that these structures represent an appreciable fraction of the amino-acid molecules.
Examining the structure and function of the cornea at the molecular level, Investigating corneal cell biology, and Translational research initiatives dedicated to improving laser refractive surgery techniques that can help address certain complications that can arise following these procedures. Hafezi is considered to be a leading expert and key opinion leader in the development and translation of CXL and its multiple applications in the field of ophthalmology, including the treatment of corneal ectatic disorders like keratoconus, pellucid marginal degeneration and post-LASIK ectasia. Hafezi and his colleagues have also pioneered the use of CXL for the treatment of corneal infections, calling the technique "photoactivated chromophore for infectious keratitis cross-linking", or PACK-CXL. Hafezi has published almost 200 articles in various peer-reviewed scientific journals since 1993, including Nature Medicine, Nature Genetics, Investigative Ophthalmology & Visual Science (IOVS), the Journal of Refractive Surgery, and Cell Death & Differentiation. His work in the field of corneal collagen cross-linking has led him to receive a number of international awards. In 2014, 2016, 2018, 2020, 2023, 2025, and 2026 his peers ranked Hafezi as one of the top 100 most influential people in ophthalmology.
Potassium (19K) has 25 known isotopes from 34K to 57K as well as 31K, as well as an unconfirmed report of 59K. Three of those isotopes occur naturally: the two stable forms 39K (93.26%) and 41K (6.72%), and the long-lived radioisotope 40K (0.012%). Naturally occurring radioactive 40K decays with a half-life of 1.248×109 years. 89% of those decays are to stable 40Ca by beta decay, whilst 11% are to 40Ar by either electron capture or positron emission. This latter decay branch has produced an isotopic abundance of argon on Earth which differs greatly from that seen in gas giants and stellar spectra. 40K has the longest known half-life for any positron-emitting nuclide. The long half-life of this primordial radioisotope is caused by a highly spin-forbidden transition: 40K has a nuclear spin of 4, while both of its decay daughters are even–even isotopes with spins of 0. 40K occurs in natural potassium in sufficient quantity that large bags of potassium chloride commercial salt substitutes can be used as a radioactive source for classroom demonstrations. 40K is the largest source of natural radioactivity in healthy animals and humans, greater even than 14C. In a human body of 70 kg mass, about 4,300 nuclei of 40K decay per second. The decay of 40K to 40Ar is used in potassium-argon dating of rocks. Minerals are dated by measurement of the concentration of potassium and the amount of radiogenic 40Ar that has accumulated. 40K has also been extensively used as a radioactive tracer in studies of weathering.
Sources: en.wikipedia.org
On 18 September 2026, the United States, Denmark, and Greenland reached an agreement in which the United States would receive the rights to an expanded military footprint in Greenland with greater security control, without, according to the Danish and Greelandic governments, conditionally transferring much military sovereignty of Greenland to the United States. The agreement was signed on 22 September 2026.
Shanimol Osman (born 30 May 1966) is an Indian politician from Kerala. She currently serves as the Deputy Speaker of the Kerala Legislative Assembly. She represents Aroor constituency in the Kerala Legislative Assembly since 21 May 2026. Shanimol is a member of the Indian National Congress.
Platelets also promote angiogenesis and tissue regeneration to maintain overall vascular integrity by releasing growth factors like vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF). Their multifunctional role displays the challenge of innovating synthetic platelets capable of effectively replicating their physiological functions.
Sources: en.wikipedia.org
Membrane osmometry is a method that relates the osmotic pressure of a solution to its number-average molar mass, but is less effective in species that can permeate the membrane. Additionally, the absolute molar mass can be determined using sedimentation equilibrium experiments or using independently determined sedimentation and diffusion coefficients. Other methods replace SEC with different separation techniques such as asymmetric flow field flow fractionation (AF4) or involve different detection systems such as matrix assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS).
In phase one, the dosages of noggin, a regulator protein, as well as rhBMP-2 were properly calibrated, and in phase two these proteins carried on synthetic calcium phosphate matrix (CPM) were then injected into the ACL region. The results of this procedure also demonstrated an improvement in the collagen fiber formation between the tendon and the bone. Hence, all three treatments were seen to improve the efficacy of tendon-to-bone healing via the different bone growth factors: SHMSP, bone protein, and rhBMP-2.
=== Relationship to Nazism and antisemitism === Various statements made by Jung in the 1930s have been cited as evidence of both contempt and sympathy for Nazism. In 1933, after the Nazis gained power in Germany, Jung became the president of the new International General Medical Society for Psychotherapy (Allgemeine Ärztliche Gesellschaft für Psychotherapie); the professional body aimed to have affiliated organizations in different countries. The German affiliated organization was the Deutsche Allgemeine Ärztliche Gesellschaft für Psychotherapie, led by Matthias Göring, an Adlerian psychotherapist, and a cousin of the prominent Nazi Hermann Göring, excluded Jews. In 1933, the society's journal, Zentralblatt für Psychotherapie, published a statement endorsing Nazi positions, and Hitler's book Mein Kampf. Jung's response to this was twofold. In "The State of Psychotherapy Today", published in 1934 in the Zentralblatt für Psychotherapie, Jung wrote: "The Aryan unconscious has a greater potential than the Jewish unconscious" and "The Jew, who is something of a nomad, has never yet created a cultural form of his own and as far as we can see never will".
Chloroplasts have their own ribosomes, which they use to synthesize a small fraction of their proteins. Chloroplast ribosomes are about two-thirds the size of cytoplasmic ribosomes (around 17 nm vs 25 nm). They take mRNAs transcribed from the chloroplast DNA and translate them into protein. While similar to bacterial ribosomes, chloroplast translation is more complex than in bacteria, so chloroplast ribosomes include some chloroplast-unique features. Small subunit ribosomal RNAs in several Chlorophyta and euglenid chloroplasts lack motifs for Shine-Dalgarno sequence recognition, which is considered essential for translation initiation in most chloroplasts and prokaryotes. Such loss is also rarely observed in other plastids and prokaryotes. An additional 4.5S rRNA with homology to the 3' tail of 23S is found in "higher" plants.
Sources: en.wikipedia.org
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.
That question is not settled. Cell culture studies have reported increased telomerase activity after treatment, but comparable evidence from controlled human trials is lacking. Any claim about telomere lengthening in people should be treated as unproven.
It has not completed the large, controlled trials required for drug approval in major jurisdictions. Most human reports involve small samples and limited follow-up. As a result, it is sold as a research chemical rather than a licensed pharmaceutical product.
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.