If you have been reading about Epithalamin 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 2026-02-22. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C14H22N4O9 | Synthetic tetrapeptide, four residues |
| Nominal mass | Approximately 390 Da | Free peptide; salt forms differ |
| Appearance | White to off-white powder | Commonly supplied lyophilised |
| Solubility class | Freely soluble in water | Also dissolves in aqueous buffer |
| Typical storage | −20 °C, desiccated | Cold packs used during transport |
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.
Most experimental work has been carried out in cell culture and animal models. Several reports describe changes in telomerase activity and proliferation in cultured cells, while rodent studies have examined lifespan, melatonin rhythm and reproductive endpoints. Human data remain limited, and much of the published clinical material consists of small trials with incomplete reporting of methods and controls. Whether the cell and animal findings translate into measurable effects in people is an open question, and the mechanistic basis of the reported telomerase changes is not fully established.
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.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography with ultraviolet detection, frequently near 214 nanometers where the peptide bond absorbs. Mass spectrometry, most often with electrospray ionization, confirms the observed molecular mass and helps separate the intact peptide from truncated or modified forms. Amino acid analysis or tandem mass spectrometry can establish residue order. Purity is commonly quoted as an area percentage, yet such values are method-dependent, and comparisons between laboratories require matching column, gradient and detection wavelength.
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.
Experts anticipate that future microfluidic-based innovations for directed evolution campaigns will be driven in the commercial space, resulting in more simple and less expensive methods and tools that can be applied to biotechnologically-relevant enzymes.
Due to patent regulations, a single manufacturer (Roche Diagnostics) distributes cTnT. A host of diagnostic companies make cTnI immunoassay methods available on many different immunoassay platforms. Cardiac troponin elevation following cardiac cell necrosis starts within 2–3 hours, peaks in approx. 24 hours, and persists for 1–2 weeks. Lateral-flow tests ("rapid diagnostic kits") have been developed for cardiac troponin I. The more basic kinds are qualitative and detect cTnI > 0.5 ng/L. More advanced types allow a quantitative readout using colorimetry, electrochemical fluorescence, or a magnetic detector.
The United States occupied Iraq between the toppling of the Ba'athist Iraqi government and the dissolution of the Coalition Provisional Authority on 28 June 2004. Thereafter, the United States remained in Iraq after obtaining United Nations Security Council approvals and resolutions, negotiated with involvement from the Transitional Government of Iraq. On 1 January 2009, the Government of Iraq obtained full responsibility for security in all of Iraq. Consequently, United States Forces – Iraq did not have responsibility for, nor control of, any ground in Iraq. Its mission was limited to defense and security cooperation only.
Most ants are generalist predators, scavengers, and indirect herbivores, but a few have evolved specialised ways of obtaining nutrition. It is believed that many ant species that engage in indirect herbivory rely on specialized symbiosis with their gut microbes to upgrade the nutritional value of the food they collect and allow them to survive in nitrogen poor regions, such as rainforest canopies. Leafcutter ants (Atta and Acromyrmex) feed exclusively on a fungus that grows only within their colonies. They continually collect leaves which are taken to the colony, cut into tiny pieces and placed in fungal gardens. Ergates specialise in related tasks according to their sizes. The largest ants cut stalks, smaller workers chew the leaves and the smallest tend the fungus. Leafcutter ants are sensitive enough to recognise the reaction of the fungus to different plant material, apparently detecting chemical signals from the fungus. If a particular type of leaf is found to be toxic to the fungus, the colony will no longer collect it. The ants feed on structures produced by the fungi called gongylidia. Symbiotic bacteria on the exterior surface of the ants produce antibiotics that kill bacteria introduced into the nest that may harm the fungi.
Sources: en.wikipedia.org
==== MeSH D12.776.624.776.355 – cyclin-dependent kinase inhibitor proteins ==== MeSH D12.776.624.776.355.100 – cyclin-dependent kinase inhibitor p15 MeSH D12.776.624.776.355.200 – cyclin-dependent kinase inhibitor p16 MeSH D12.776.624.776.355.300 – cyclin-dependent kinase inhibitor p18 MeSH D12.776.624.776.355.400 – cyclin-dependent kinase inhibitor p19 MeSH D12.776.624.776.355.500 – cyclin-dependent kinase inhibitor p21 MeSH D12.776.624.776.355.600 – cyclin-dependent kinase inhibitor p27 MeSH D12.776.624.776.355.700 – cyclin-dependent kinase inhibitor p57
Fentanyl has started to be mixed into illicitly manufactured opioids and benzodiazepines. Fentanyl contamination in cocaine, methamphetamine, ketamine, MDMA, and other drugs is common. A kilogram of heroin laced with fentanyl may sell for more than US$100,000, but the fentanyl itself may be produced far more cheaply, for about US$6,000 per kilogram. While Mexico and China are the primary source countries for fentanyl and fentanyl-related substances trafficked directly into the United States, India is emerging as a source for finished fentanyl powder and fentanyl precursor chemicals. The United Kingdom illicit drug market is no longer reliant on China, as domestic fentanyl production is replacing imports. The intravenous dose causing 50% of opioid-naive experimental subjects to die (LD50) is "3 mg/kg in rats, 1 mg/kg in cats, 14 mg/kg in dogs, and 0.03 mg/kg in monkeys." The LD50 in mice has been given as 6.9 mg/kg by intravenous administration, 17.5 mg/kg intraperitoneally, 27.8 mg/kg by oral administration, The safety margin in rats is ~280. The LD50 in humans is unknown. In 2023, overdose deaths in the US and Canada reached record numbers. While overdoses involving fentanyl in the United States have decreased in 2024, the overall percentage of overdoses involving fentanyl has remained stable between 70% and 80% from 2021 to 2024. According to a 2023 report from the United Nations Office on Drugs and Crime (UNODC), the increased numbers of deaths are not related to an increased number of users but to the lethal effects of fentanyl itself.
=== Space science and planetary research === Space science and planetary research at the University of Arizona are largely conducted through the Lunar and Planetary Laboratory (LPL), which has led or contributed to numerous NASA missions. The university received more than $325 million for the LPL to lead NASA's 2007–08 Phoenix Mars Mission, which explored the Martian Arctic. It later received another $800 million for the OSIRIS-REx mission, the first mission in U.S. history to collect a sample from an asteroid. The LPL's contributions to the Cassini mission orbiting Saturn were larger than those of any other university in the world. University researchers designed and operated the spacecraft's atmospheric radiation and imaging investigations. The university also operates the HiRISE camera aboard the Mars Reconnaissance Orbiter. The spacecraft reached Mars in March 2006 after traveling 300 million miles. The University of Arizona-designed camera was led by planetary scientist Alfred McEwen, the project's principal investigator. HiRISE captured high-resolution images of the planet. In 2011, University of Arizona alumnus and planetary scientist Lujendra Ojha and his research team used HiRISE imagery to identify evidence of liquid water on the surface of Mars. NASA confirmed the discovery in 2015. The university receives more NASA grants annually than the next nine top NASA-Jet Propulsion Laboratory-funded universities combined. In August 2007, the University of Arizona, under the direction of planetary scientist Peter Smith, led the Phoenix Mars Mission.
== See also == Black box Bus analyzer Computer data logging: logging APIs, server logs & syslog, web logging & web counters Continuous emissions monitoring system Runtime intelligence Sequence of events recorder SensorML Shock and vibration data logger Temperature data logger
=== Determining quality === Once tempeh is produced, it is divided into three categories based on its quality: good, unfinished, and inedible. Good tempeh includes beans that are bound into a firm, compact cake by a dense, uniform, white mycelium, which should permeate the entire cake; the beans should be barely visible. The odor of good tempeh should be pleasant, clean, subtly sweet or resemble the aroma of mushrooms. The entire tempeh should lift as a single, cohesive cake without crumbling when shaken gently. Unfinished tempeh has beans that are bound together loosely by a sparse white mycelium, hence it crumbles easily. Unfinished tempeh should be incubated longer unless it has been incubated more than eight hours past the recommended time. If it has been incubated for enough time and still remains unfinished, it should be discarded. Inedible tempeh has beans with foul odor, resembling strong ammonia or alcohol, indicating the development of undesirable bacteria due to excess moisture or overheating. Inedible tempeh cake is wet, slimy, and mushy with a collapsed structure. Its color is tan to brown and mold develops in sparse patches.
Sources: en.wikipedia.org
== Spontaneous resolution and related specialized techniques == Via the process known as spontaneous resolution, 5-10% of all racemates crystallize as mixtures of enantiopure crystals. This phenomenon allowed Louis Pasteur to separate left-handed and right-handed sodium ammonium tartrate crystals. These experiments underpinned his discovery of optical activity. In 1882 he went on to demonstrate that by seeding a supersaturated solution of sodium ammonium tartrate with a d-crystal on one side of the reactor and a l-crystal on the opposite side, crystals of opposite handedness will form on the opposite sides of the reactor. Spontaneous resolution has also been demonstrated with racemic methadone. In a typical setup 50 grams dl-methadone is dissolved in petroleum ether and concentrated. Two millimeter-sized d- and l-crystals are added and after stirring for 125 hours at 40 °C two large d- and l-crystals are recovered in 50% yield. Another form of direct crystallization is preferential crystallization also called resolution by entrainment of one of the enantiomers. For example, seed crystals of (−)-hydrobenzoin induce crystallization of this enantiomer from an ethanol solution of (±)-hydrobenzoin.
==== Orientation ==== Most often, a burial will be oriented to a specific direction for religious purposes, as are the case for persons of the Abrahamic faiths. Standard Jewish burials are made supine east-west, with the head at the western end of the grave, in order to face Jerusalem. In other cases, the body may be buried on a north-south axis, or, simply facing towards the exit of the cemetery or burial grounds. This is done in order to facilitate the return to Israel foretold of all those who are resurrected at the end of time following the coming of the Messiah. Historically, Christian burials followed similar principles, where the body was placed east-west, to mirror the layout of Christian churches, which were themselves oriented as such for much the same reason; to view the coming of Christ on Judgment day (Eschaton). In many Christian traditions, ordained clergy are traditionally buried in the opposite orientation, and their coffins carried likewise, so that at the General Resurrection they may rise facing, and ready to minister to, their people. In an Islamic funeral, the grave should be aligned perpendicular to the Qibla (the direction to the Kaaba in Mecca) with the face turned to the right along the Qibla.
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Einstein hosts one of the three inaugural MSTPs launched by the National Institutes of Health (NIH) in 1964. This fully-funded dual doctoral MD/PhD program provide integrated graduate and clinical training for aspiring physician-scientists. The MSTP includes waived tuition, a stipend, subsidized housing, and a sesquiennial retreat to the Edith Macy Conference Center. The first year of the program integrates medical school preclerkship curriculum with graduate school coursework and lab rotations. In the second year, trainees complete preclinical medical courses, take USMLE Step 1, and choose a PhD advisor based on lab rotations. Years three to five focus on PhD research, publication, and optional clinical activities, followed by intensive clinical clerkships in years six and seven after dissertation defense. While working in the lab, students engage in both pathology case studies and clinics to maintain clinical skills.
== Manufacturing == Propofol, as a commercial sterile emulsified formulation, is considered difficult to manufacture. It was initially formulated in Cremophor for human use, but this original formulation was implicated in an unacceptable number of anaphylactic events. It was eventually manufactured as a 1% emulsion in soybean oil. Sterile emulsions represent complex formulation, the stability of which is dependent on the interplay of many factors such as micelle size and distribution.
Sources: en.wikipedia.org
No. Epithalamin is a heterogeneous peptide fraction obtained from pineal gland extract and contains many components. Epitalon is a single synthetic tetrapeptide with the sequence Ala-Glu-Asp-Gly. Researchers synthesised the shorter peptide while attempting to identify active sequences within the extract.
No endogenous peptide with this exact sequence has been described as a circulating hormone or signalling molecule. The tetrapeptide was designed as a synthetic analogue based on fragments observed in pineal preparations. Any activity discussed in the literature therefore refers to administered material rather than to a natural pool of the compound.
It is not an approved medicine in major jurisdictions and does not appear in the major pharmacopoeias. Material is usually distributed as a research chemical or laboratory reagent. Such labelling places handling responsibility on the purchaser and does not indicate that a regulatory body has reviewed the substance.
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.