A practical reference on Pineal peptide: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-02-06. Anything still debated is marked as such rather than presented as settled.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Sequence | Ala-Glu-Asp-Gly | Written in three-letter amino acid code |
| Single-letter code | AEDG | Form used in most catalogue entries |
| Typical purity specification | 95 percent or higher | Value read from the HPLC chromatogram |
| Storage, dry solid | Minus 20 degrees Celsius, desiccated | Sealed container, protected from light |
| Handling, solution | Divide into single-use portions | Limits losses from freeze-thaw cycling |
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.
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.
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.
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.
Identity and purity are checked by reversed-phase high-performance liquid chromatography, usually with ultraviolet detection near 214 nanometres, where the peptide bond absorbs. Mass spectrometry confirms the expected mass and reveals whether truncation products or adducts are present. Acid hydrolysis followed by amino acid analysis gives the residue ratio, which should approximate one alanine, one glutamate, one aspartate and one glycine. Counter-ions such as acetate or trifluoroacetate remain in the dried product and lower net peptide content, so a stated purity figure on a label does not by itself describe how much peptide a vial holds.
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.
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.
== Medical Uses == Treosulfan in combination with fludarabine is indicated as part of conditioning treatment prior to allogeneic haematopoietic stem cell transplantation in adults with malignant and non malignant diseases, and in children older than one month with malignant diseases.
Acetyl transacylase transfers the acetyl group of acetyl-CoA onto the sulfhydryl group of Acyl Carrier Protein (ACP), releasing CoA and forming acetyl-ACP. An equivalent reaction occurs for malonyl-CoA, in which malonyl transacylase transfers the malonyl group from malonyl-CoA to the sulfhydryl group of Acyl Carrier Protein (ACP), releasing CoA and forming malonyl-ACP. These two reactions are essential, as they prime the acetyl and malonyl groups for condensation in the subsequent chain elongation reaction step. After the production of acetyl-ACP and malonyl-ACP, fatty acid synthesis begins to cycle through repetitions of the following reaction sequence: condensation → reduction → dehydration → reduction. Ultimately, this elongation reaction sequence repeats through 7 cycles to form one molecule of (16C) palmitate, as malonyl-CoA (the carbon donor) adds 2 carbons to the growing chain per cycle. During the third reaction of fatty acid synthesis, acetyl-ACP and malonyl-ACP undergo a condensation reaction catalyzed by the enzyme β-ketoacyl-ACP synthase (also known as acyl-malonyl-ACP condensing enzyme), which produces the four-carbon acetoacetyl-ACP molecule and one molecule of CO2. Notably, the reaction of two-carbon acetyl-ACP with three-carbon malonyl-ACP is more favorable than that of two, two-carbon acetyl-ACP molecules reacting together. The fourth step of fatty acid elongation is the reduction of acetoacyl-ACP to β-hydroxyacyl-ACP, in a reaction catalyzed by 3-ketoacyl-ACP reductase.
The South African Border War, also known as the Namibian War of Independence, and sometimes denoted in South Africa as the Angolan Bush War, was a largely asymmetric conflict that occurred in Namibia (then South West Africa), Zambia, and Angola from 26 August 1966 to 21 March 1990. It was fought between the South African Defence Force (SADF) and the People's Liberation Army of Namibia (PLAN), an armed wing of the South West African People's Organisation (SWAPO). The South African Border War was closely intertwined with the Angolan Civil War.
First generation vaccines are whole-organism vaccines – either live and weakened, or killed forms. Live, attenuated vaccines, such as smallpox and polio vaccines, are able to induce killer T-cell (TC or CTL) responses, helper T-cell (TH) responses and antibody immunity. However, attenuated forms of a pathogen can convert to a dangerous form and may cause disease in immunocompromised vaccine recipients (such as those with AIDS). While killed vaccines do not have this risk, they cannot generate specific killer T-cell responses and may not work at all for some diseases. Second generation vaccines were developed to reduce the risks from live vaccines. These are subunit vaccines, consisting of specific protein antigens (such as tetanus or diphtheria toxoid) or recombinant protein components (such as the hepatitis B surface antigen). They can generate TH and antibody responses, but not killer T cell responses. RNA vaccines and DNA vaccines are examples of third generation vaccines. In 2016 a DNA vaccine for the Zika virus began testing at the National Institutes of Health. Separately, Inovio Pharmaceuticals and GeneOne Life Science began tests of a different DNA vaccine against Zika in Miami. Manufacturing the vaccines in volume was unsolved as of 2016. Clinical trials for DNA vaccines to prevent HIV are underway. mRNA vaccines such as BNT162b2 were developed in the year 2020 with the help of Operation Warp Speed and massively deployed to combat the COVID-19 pandemic.
The Canadian Penning Trap Mass Spectrometer (CPT) is one of the major pieces of experimental equipment that is installed on the ATLAS superconducting heavy-ion linac facility at the Physics Division of the Argonne National Laboratory. It was developed and operated by physicist Guy Savard and a collaboration of other scientists at Argonne, the University of Manitoba, McGill University, Texas A&M University and the State University of New York.
Sources: en.wikipedia.org
Contrail, also known as vapor trail – Long, thin artificial clouds that sometimes form behind aircraft Dilution (equation) – Chemistry concept Evaporation – Vaporization of a liquid from its surface Henry's law – Gas law regarding proportionality of dissolved gas Vaporizer (disambiguation)
Incandescent lights are filled with argon, to preserve the filaments at high temperature from oxidation. It is used for the specific way it ionizes and emits light, such as in plasma globes and calorimetry in experimental particle physics. Gas-discharge lamps filled with pure argon provide lilac/violet light; with argon and some mercury, blue light. Argon is also used for blue and green argon-ion lasers.
===== Triple combination ===== The combination of metformin with dapagliflozin and saxagliptin is available in the United States as Qternmet XR. The combination of metformin with pioglitazone and glibenclamide is available in India as Accuglim-MP, Adglim MP, and Alnamet-GP; and in the Philippines as Tri-Senza. The combination of metformin with pioglitazone and lipoic acid is available in Turkey as Pional.
From the 17th century onward, tobacco smoking became virtually central to European social, economic, and cultural history and beyond, entrenching itself in daily rituals, trade networks, and even international conflicts. By the late 17th century, tobacco was used not only for smoking but also as an insecticide. After World War II, over 2,500 tons of nicotine insecticide were used worldwide, but by the 1980s the use of nicotine insecticide had declined below 200 tons. This was due to the availability of other insecticides that are cheaper and less harmful to mammals. The nicotine content of popular American-brand cigarettes has increased over time, and one study found that there was an average increase of 1.78% per year between the years of 1998 and 2005. Although methods of production of synthetic nicotine have existed for decades, it was believed that the cost of making nicotine by laboratory synthesis was cost prohibitive compared to extracting nicotine from tobacco. However, recently synthetic nicotine started to be found in different brands of e-cigarettes and oral pouches and marketed as "tobacco-free".
== Units of measurement == BAC is the mass of alcohol per unit volume of blood. The SI unit is kilogram per cubic metre (kg/m3), though it is commonly reported as grams per liter (g/L). Reporting conventions vary by country. In the United States and several other countries, BAC is expressed as a percentage, such as 0.05%. This corresponds to 0.05 grams per deciliter of blood. The same concentration may be expressed as 0.5‰ or 50 mg% in other jurisdictions.
Sources: en.wikipedia.org
Diffusion force caused by concentration gradient—all particles including ions diffuse from higher concentration to lower. Electrostatic force caused by electrical potential gradient—cations like protons H+ diffuse down the electrical potential, anions in the opposite direction. These two gradients together can be expressed as an electrochemical gradient, providing energy for abiogenic synthesis. The proton motive force measures the potential energy stored as proton and voltage gradients across a membrane (differences in proton concentration and electrical potential). The surfaces of mineral particles inside deep-ocean hydrothermal vents have catalytic properties similar to those of enzymes, and can create simple organic molecules, such as methanol (CH3OH) and formic, acetic, and pyruvic acids out of the dissolved CO2 in the water, if driven by an applied voltage or by reaction with H2 or H2S. Starting in 1981, researchers proposed that life might have started at hydrothermal vents, that spontaneous chemistry in the Earth's crust driven by rock–water interactions at disequilibrium thermodynamically underpinned life's origin, and that the founding lineages of the archaea and bacteria were H2-dependent autotrophs that used CO2 as their terminal acceptor in energy metabolism. In 2016, Martin suggested that the LUCA "may have depended heavily on the geothermal energy of the vent to survive". That same year, RNA was produced in synthetic alkaline hydrothermal chimneys simulating deep-sea vents. Researchers were able to generate RNA oligomers of up to 4 units in length.
=== Non-modifiable === Scandinavian or Northern European ancestry; Dupuytren's has been called the "Viking disease", though it is also widespread in some Mediterranean countries, e.g., Spain and Bosnia. Dupuytren's is uncommon among groups including Chinese and Africans. In June 2023 a study found that gene variants that were inherited from Neanderthals dramatically increased the odds of developing the condition Male sex; men are 80% more likely to develop the condition Age of 50 or over (5% to 15% of men in that group in the US); the likelihood of getting Dupuytren's disease increases with age A family history (60% to 70% of those affected have a genetic predisposition to Dupuytren's contracture)
== Non-human infections == Streptococcus agalactiae was historically studied as a disease of cattle that harmed milk production, leading to its name "agalactiae" which means "absence of milk". Strains of bovine and human bacteria are generally interchangeable, with evidence of transmission from animals to humans and vice versa.
== Further reading == Carruthers JD, Fagien S, Joseph JH, Humphrey SD, Biesman BS, Gallagher CJ, et al. (January 2020). "DaxibotulinumtoxinA for Injection for the Treatment of Glabellar Lines: Results from Each of Two Multicenter, Randomized, Double-Blind, Placebo-Controlled, Phase 3 Studies (SAKURA 1 and SAKURA 2)". Plastic and Reconstructive Surgery. 145 (1): 45–58. doi:10.1097/PRS.0000000000006327. PMC 6940025. PMID 31609882. Solish N, Carruthers J, Kaufman J, Rubio RG, Gross TM, Gallagher CJ (December 2021). "Overview of DaxibotulinumtoxinA for Injection: A Novel Formulation of Botulinum Toxin Type A". Drugs. 81 (18): 2091–2101. doi:10.1007/s40265-021-01631-w. PMC 8648634. PMID 34787840.
Sources: en.wikipedia.org
Reversed-phase high-performance liquid chromatography is run alongside mass spectrometry. The chromatogram separates components and gives a purity figure, while the mass spectrum confirms that the measured molecular mass matches the expected sequence. Neither measurement on its own is treated as sufficient.
Long-term holding is usually at minus twenty degrees Celsius in a sealed, desiccated container. A refrigerator is adequate for short intervals before use. Light exposure is normally avoided as well. Allowing a cold container to warm before opening reduces moisture condensation on the contents.
Repeated cycles are generally avoided. Each freeze and thaw can promote aggregation or loss of peptide to container surfaces, which reduces the amount available for later work. Dividing a solution into single-use portions at the outset is the usual way to limit this problem.
Epitalon is a synthetic four-amino-acid peptide with the sequence alanine–glutamate–aspartate–glycine, also written AEDG. It was developed in Russian gerontology research and is studied for proposed effects on telomerase, melatonin regulation, and neuroendocrine function. It is not an approved pharmaceutical in the United States or the European Union.