This is a working overview of pineal peptides, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2025-08-12. Anything still debated is marked as such rather than presented as settled.
Regulatory treatment differs by country. No formulation of epitalon holds a marketing authorisation as a medicine in the United States or the European Union, where material sold for laboratory use is handled as a research chemical and is not intended for human consumption. In Russia, several short peptide preparations from the same institute's peptide series are registered medicinal products, and epitalon appears in that national context. Elsewhere it is frequently offered as a cosmetic ingredient, a category with lighter requirements. Advertising claims about longevity or disease prevention are restricted in most jurisdictions, which limits how sellers describe the compound.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Storage temperature, solid | Approximately -20 C | Sealed, desiccated, protected from light |
| Typical identity method | Electrospray mass spectrometry | Protonated ion expected near 391 |
| Typical purity method | Reversed-phase HPLC | Ultraviolet detection near 214 nm |
| Common synonyms | Epithalon, epithalone, AEDG | Spelling variants appear in supplier catalogues |
| Solution stability | Days at 2-8 C | Hydrolysis and deamidation limit shelf life |
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.
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.
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.
No pharmacopoeial monograph exists for this peptide, so quality rests on the supplier's internal specifications and on whatever independent testing a purchaser arranges. Certificates of analysis differ widely in which tests they report and in the limits applied. The counter-ion introduced during purification, commonly acetate or trifluoroacetate, changes the net peptide content of a given mass of powder, so two samples of equal weight may not contain equal amounts of the active sequence. Third-party laboratories can verify purity, identity, residual solvents, and counter-ion content for a fee, which makes documentation more informative than labelling.
Verification of a sample usually begins with reversed-phase high-performance liquid chromatography, which resolves the peptide from truncated sequences and other impurities and expresses purity as a percentage of total peak area. Mass spectrometry by electrospray ionisation or matrix-assisted laser desorption supplies an independent check, because the measured mass can be compared against the theoretical value for AEDG. Amino acid analysis or tandem mass spectrometry sequencing can confirm residue order. Each of these methods answers a different question: a purity figure does not establish identity, and an identity match does not establish how much of the material is intact peptide.
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.
==== Germany ==== The Federal Office for Radiation Protection has developed a radon map of Germany. The EU Directive 2013/59/Euratom (Radiation Protection Basic Standards Directive) introduced reference levels and the possibility for workers to have their workplace tested for radon exposure. In Germany, it was implemented in the Radiation Protection Act (Chapter 2 or Sections 124-132 StrlSchG) § 124-132 StrlSchG (in German) and the amended Radiation Protection Ordinance (Part 4 Chapter 1, Sections 153-158 StrlSchV). § 153-158 Act of (in German) The new radon protection regulations for workplaces and new residential buildings have been binding since January 2019. Extensive radon contamination and radon precautionary areas have been determined by the ministries of the environment of the federal states (as of June 15, 2021).
== Synthesis == Endorphin precursors are primarily produced in the pituitary gland. All three types of endorphins are fragments of the precursor protein proopiomelanocortin (POMC). At the trans-Golgi network, POMC binds to a membrane-bound protein, carboxypeptidase E (CPE). CPE facilitates POMC transport into immature budding vesicles. In mammals, proprotein convertase 1 (PC1) cleaves POMC into adrenocorticotropin (ACTH) and beta-lipotropin (β-LPH). β-LPH, a pituitary hormone with little opioid activity, is then continually fragmented into different peptides, including α-endorphin, β-endorphin, and γ-endorphin. Proprotein convertase 2 (PC2) is responsible for cleaving β-LPH into β-endorphin and γ-lipotropin. Formation of α-endorphin and γ-endorphin results from proteolytic cleavage of β-endorphin.
=== Gastrointestinal tract === In the gastrointestinal tract, KOR is expressed on myenteric and submucosal plexus neurons, where they modulate intestinal motility and secretion. Both KOR and MOR mRNAs are expressed in all investigated gastrointestinal regions in one study, with the stomach and proximal colon displaying the highest expression levels, and the duodenum exhibiting the lowest. KOR in the proximal colon represented 40% of the amount found in the brain. A higher number of neurons expressing KOR-like immunoreactivity are visualized in the myenteric plexus with a smaller number in the submucosal plexus, unlike the distribution pattern of MORs.
The former has been found safe in people with well-controlled HIV, but was not tried in immunocompromised people due to replication concerns. The latter is considered safe for immunocompromised people by the US CDC,.
BioShock was bundled with The Elder Scrolls IV: Oblivion as a double pack on PC and Xbox 360 on July 7, 2009. A port to OS X systems was made by Feral Interactive and released in October 2009. In early 2008, IG Fun secured the rights to develop and publish a mobile phone version of BioShock. This version was developed as a top-down, two-dimensional platformer that attempted to recreate most of the plot and game elements of the original title; IG Fun worked with Irrational to determine the critical story elements they wanted to keep in the game. IG Fun recognized they would not be able to include the full storyline within a single mobile title, and so planned to split the title into three "episodes". Only the first episode was released. Another mobile port was developed by Tridev, known as BioShock 3D, released in 2010. Several parts of the game were reduced to single image graphics and the main gameplay engine had to use low-resolution and low-polygon models due to the limitations of mobile phones at the time of its release. A port to iOS devices done by the 2K China studio was released on August 27, 2014. The iOS version is content complete and functionally equivalent to the original Xbox 360 and Windows version, featuring either the use of touch-screen virtual gamepad controls or the use of a Bluetooth-enabled controller, and with a graphics engine optimized for iOS devices.
Sources: en.wikipedia.org
Emotion focused therapy/Emotionally focused therapy (EFT), not to be confused with Emotional Freedom Techniques, was initially informed by humanistic–phenomenological and Gestalt theories of therapy. "Emotion Focused Therapy can be defined as the practice of therapy informed by an understanding of the role of emotion in psychotherapeutic change. EFT is founded on a close and careful analysis of the meanings and contributions of emotion to human experience and change in psychotherapy. This focus leads therapist and client toward strategies that promotes the awareness, acceptance, expression, utilization, regulation, and transformation of emotion as well as corrective emotional experience with the therapist. The goals of EFT are strengthening the self, regulating affect, and creating new meaning". Similarly to some Psychodynamic therapy approaches, EFT pulls heavily from attachment theory. Pioneers of EFT are Les Greenberg and Sue Johnson. EFT is often used in therapy with individuals, and may be especially useful for couples therapy. Founded in 1998, Sue Johnson and others lead the International Centre for Excellence in Emotion Focused Therapy (ICEEFT) where clinicians can find EFT training internationally. EFT is also a commonly chosen modality to treat clinically diagnosable trauma.
==== Reversibility and irreversibility ==== In many cases, denaturation is reversible (the proteins can regain their native state when the denaturing influence is removed). This process can be called renaturation. This understanding has led to the notion that all the information needed for proteins to assume their native state was encoded in the primary structure of the protein, and hence in the DNA that codes for the protein, the so-called "Anfinsen's thermodynamic hypothesis". Denaturation can also be irreversible. This irreversibility is typically a kinetic, not thermodynamic irreversibility, as a folded protein generally has lower free energy than when it is unfolded. Through kinetic irreversibility, the fact that the protein is stuck in a local minimum can stop it from ever refolding after it has been irreversibly denatured.
The chief characteristic of proteins that allows their diverse set of functions is their ability to bind other molecules specifically and tightly. The region of the protein responsible for binding another molecule is known as the binding site and is often a depression or "pocket" on the molecular surface. This binding ability is mediated by the tertiary structure of the protein, which defines the binding site pocket, and by the chemical properties of the surrounding amino acids' side chains. Protein binding can be extraordinarily tight and specific; for example, the ribonuclease inhibitor protein binds to human angiogenin with a sub-femtomolar dissociation constant (< 10−15 M) but does not bind at all to its amphibian homolog onconase (> 1 M). Extremely minor chemical changes such as the addition of a single methyl group to a binding partner can sometimes suffice to nearly eliminate binding; for example, the aminoacyl tRNA synthetase specific to the amino acid valine discriminates against the very similar side chain of the amino acid isoleucine. Proteins can bind to other proteins as well as to small-molecule substrates. When proteins bind specifically to other copies of the same molecule, they can oligomerize to form fibrils; this process occurs often in structural proteins that consist of globular monomers that self-associate to form rigid fibers.
Having a front end means that this part of the body encounters stimuli, such as food, favouring cephalisation, the development of a head with sense organs and a mouth. Many bilaterians have a combination of circular muscles that constrict the body, making it longer, and an opposing set of longitudinal muscles, that shorten the body; these enable soft-bodied animals with a hydrostatic skeleton to move by peristalsis. They also have a gut that extends through the basically cylindrical body from mouth to anus. Many bilaterian phyla have primary larvae which swim with cilia and have an apical organ containing sensory cells. However, over evolutionary time, descendant spaces have evolved which have lost one or more of each of these characteristics. For example, adult echinoderms are radially symmetric (unlike their larvae), while some parasitic worms have extremely simplified body structures. Genetic studies have considerably changed zoologists' understanding of the relationships within the Bilateria. Most appear to belong to two major lineages, the protostomes and the deuterostomes. It is often suggested that the basalmost bilaterians are the Xenacoelomorpha, with all other bilaterians belonging to the subclade Nephrozoa. However, this suggestion has been contested, with other studies finding that xenacoelomorphs are more closely related to Ambulacraria than to other bilaterians.
Indium has greater solubility in liquid mercury than any other metal (more than 50 mass percent of indium at 0 °C). Indium displays a ductile viscoplastic response, found to be size-independent in tension and compression. However it does have a size effect in bending and indentation, associated to a length-scale of order 50–100 μm, significantly large when compared with other metals.
Sources: en.wikipedia.org
=== Evaluating approaches to AI === No established unifying theory or paradigm has guided AI research for most of its history. The unprecedented success of statistical machine learning in the 2010s eclipsed all other approaches (so much so that some sources, especially in the business world, use the term "artificial intelligence" to mean "machine learning with neural networks"). This approach is mostly sub-symbolic, soft and narrow.
The same day, Greenland's government mulled the creation of a task force with representatives from local authorities to prepare residents for potential disruptions to daily life, including guidance recommending that households keep five days of food supplies. Additionally, PM Jens-Frederik Nielsen stated that a military conflict could not be ruled out. The Joint Arctic Command announced plans to expand its military exercises, potentially conducting them on a year-round basis. A Danish defence analyst interviewed by Times Radio said Denmark discussed plans to station around 1,000 Danish ground forces in Greenland, in addition to other capabilities and allied contributions. An investigation by Times Radio suggested that it would be very hard for the US to successfully invade Greenland due to a combination of lack of US Arctic capabilities, the geography of Greenland, and Danish knowledge of the area, preparedness and Arctic training.
=== Neuronal membrane === The brain preferentially uses choline to synthesize acetylcholine. This limits the amount of choline available to synthesize phosphatidylcholine. When the availability of choline is low or the need for acetylcholine increases, phospholipids containing choline can be catabolized from neuronal membranes. These phospholipids include sphingomyelin and phosphatidylcholine. Supplementation with citicoline can increase the amount of choline available for acetylcholine synthesis and aid in rebuilding membrane phospholipid stores after depletion. Citicoline decreases phospholipase stimulation. This can lower levels of hydroxyl radicals produced after an ischemia and prevent cardiolipin from being catabolized by phospholipase A2. It can also work to restore cardiolipin levels in the inner mitochondrial membrane.
== Conferences == In May 2010, the Foundation sponsored a conference on "Creatine in Health, Medicine and Sport", held at Downing College, Cambridge. This was followed by the first Macular Carotenoids Conference also held at Downing College in July 2011 which led to a book, Carotenoids and Retinal Disease. Further conferences on Macular Carotenoids at Downing College were held in 2013 and 2015. The BON (Brain and Ocular Nutrition) Conference is to be held 11–13 July 2018 again at Downing College, Cambridge.
Sources: en.wikipedia.org
The solid is kept cold, dry and dark, typically at minus twenty degrees Celsius, in a sealed container with desiccant. Dissolved material is kept refrigerated and used promptly. Freezing and thawing a solution repeatedly is avoided because it accelerates degradation.
Reversed-phase chromatography with ultraviolet detection gives a purity percentage, while mass spectrometry confirms identity. Amino acid analysis checks the residue composition. Buyers typically request a certificate of analysis showing these measurements for the specific lot.
It is not authorised as a medicine in the United States or the European Union. Material is sold there as a research chemical or cosmetic ingredient. Some related short peptides are registered drugs in Russia, which is a distinct national situation rather than a general approval.
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.