Everything below concerns tetrapeptide. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2025-10-31. Numbers and descriptions here follow the published literature rather than marketing material.
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.
The four residues give epitalon a molecular formula of C14H22N4O9 and a molecular weight near 390.35 daltons. The presence of two acidic residues, glutamate and aspartate, makes the free peptide strongly acidic, while the alanine and glycine ends provide neutral, nonpolar character. This combination produces a molecule with substantial water solubility. Because there are no cysteine, methionine, or tryptophan residues, the peptide lacks the most common oxidation-sensitive side chains, which simplifies handling compared with many longer peptides.
The proposed relationship between epitalon and pineal function is a central part of its background. Khavinson's group reported that short peptides corresponding to regions of larger pineal proteins could influence gene expression in cells. Epitalon was framed as a synthetic analogue of an active fragment rather than a direct isolation product. Whether the tetrapeptide reproduces the effects of the parent extract is an open question, because comparative studies are limited and the parent extract itself is not a single defined substance.
| 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.
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.
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 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.
Published evidence comes mainly from Russian-language journals and from a single research group, with small sample sizes and limited independent replication. A few laboratories outside that group have examined related peptides and reported weaker or absent telomerase effects, so the central claim is best described as contested rather than settled. Rodent studies report modest changes in some ageing markers and in survival, but designs vary and control conditions are often sparse. No large randomised trial in humans has been published, and long-term safety data in healthy populations are correspondingly thin.
In February 2019, Sergey Lavrov stated that the withdrawal from the INF Treaty would not lead to "a new Cold War". The Russian news agency TASS reported the Russian Foreign Minister Sergey Lavrov stating: "I don't think that we should talk about a new Cold War", adding that the US development of low-yield nuclear warheads (the first of which entered production in January 2019) had increased the potential for the use of nuclear weapons. Speaking to the press in Berlin on 8 November 2019, a day before the 30th anniversary of the fall of the Berlin Wall, US secretary of state Mike Pompeo warned of the dangers posed to the West by Russia and China. He said: "Today, Russia – led by a former KGB officer once stationed in Dresden [Vladimir Putin] – invades its neighbours and slays political opponents". Jonathan Marcus of the BBC opined that Pompeo "appeared to be declaring the outbreak of a second [Cold War]".
=== Julia Braverman-Graham === Julia Braverman-Graham (Erika Christensen) is Sydney and Victor's mother, Joel's wife, and Zeek and Camille's fourth and youngest child and second daughter. She is a lawyer at a top corporate firm while her husband, Joel, supports her ambitions by serving as a stay-at-home dad to their daughter. Julia is sometimes competitive and it is difficult for her to let go and relax. Julia's go-getting personality and by-the-book approach is the opposite of her sister Sarah's, but they turn to one another for support. During the second season, Joel and Julia are celebrating their eight-year anniversary. After unsuccessfully trying to conceive a second child, Julia is told she has scarring in her uterus and that it will be extremely difficult for her to conceive again. Julia and Joel decide to adopt a young boy named Victor. During the fourth season, after missing Sydney's dance recital and Victor's first baseball game, as well as a discovery deadline for the law firm (a costly mistake for the firm), she quits her job at the firm. She then attempts to become a stay-at-home mom while Joel goes back to work. In season five, Julia begins to struggle with staying at home and feeling out of place. She begins a friendship with Ed, a dad at her children's school, and it begins to turn into an emotional affair. Eventually she sees the dangers and goes to break it off, but instead they kiss. Later in the season, after separating with Joel over her relationship with Ed, Julia has a one-night stand with Mr.
Split-thickness A split-thickness skin graft (STSG) includes the epidermis and part of the dermis. Its thickness depends on the donor site and the needs of the person receiving the graft. It can be processed through a skin mesher which makes apertures onto the graft, allowing it to expand up to four times its size. For larger expansions the modified MEEK technique can be used, allowing it to expand up to nine times its size. Split-thickness grafts are frequently used as they can cover large areas and the rate of autorejection is low. The same site can be harvested again after six weeks. The donor site heals by re-epithelialisation from the dermis and surrounding skin and requires dressings. Full-thickness A full-thickness skin graft consists of the epidermis and the entire thickness of the dermis. The donor site is either sutured closed directly or covered by a split-thickness skin graft. Composite graft A composite graft is a small graft containing skin and underlying cartilage or other tissue. Donor sites include, for example, ear skin and cartilage to reconstruct nasal alar rim defects.
== As a drug target == NAMPT has increasingly been researched as a potential drug target, with activators of NAMPT having potential applications as anti-aging drugs, while inhibitors of NAMPT may be useful for the treatment of certain forms of cancer. Because cancer cells utilize increased glycolysis, and because NAD enhances glycolysis, iNAMPT is often amplified in cancer cells. APO866 (FK866) is an experimental drug that inhibits this enzyme. It was tested for treatment of advanced melanoma, cutaneous T-cell lymphoma (CTL), and refractory or relapsed B-chronic lymphocytic leukemia, but was dropped from development due to disappointing efficacy results in trials. However, it has been shown to inhibit epithelial–mesenchymal transition (EMT) and inhibit tumor-associated angiogenesis, and may be useful for other medical indications. Anti-aging biomedical company Calico has licensed the experimental P7C3 analogs involved in enhancing iNAMPT activity. P7C3 compounds have been shown in a number of publications to be beneficial in animal models for age-related neurodegeneration.
=== Solid culture media === Agarose plate may sometimes be used instead of agar for culturing organisms as agar may contain impurities that can affect the growth of the organism or some downstream procedures such as polymerase chain reaction (PCR). Agarose is also harder than agar and may therefore be preferable where greater gel strength is necessary, and its lower gelling temperature may prevent causing thermal shock to the organism when the cells are suspended in liquid before gelling. It may be used for the culture of strict autotrophic bacteria, plant protoplast, Caenorhabditis elegans, other organisms and various cell lines.
Sources: en.wikipedia.org
=== Thermal modulation === Thermal modulators use broad temperature differentials (by way of hot and cold jets) to trap and release analytes eluting out of the primary column. Commercial devices typically use two-stage modulation either via a quad jet approach (where there are two pairs of jets to trap and release the analytes on two different sections of the column) or a delay loop (where the column loops back between a single pair of jets). Both approaches ensure there are two opportunities to focus the analytes. There are also different versions of thermal modulators based on what is used to cool the cold jet (a stream of dry gas, usually air or nitrogen). Liquid nitrogen cooled loop system provide the lowest temperature for thermal modulation, meaning it is capable of modulating volatiles from C2. However, there is the compromise that liquid nitrogen is expensive and causes additional health and safety concerns. Alternatively, consumable-free thermal modulators are available that use a closed cycle refrigeration unit to cool the cold jet.
As part of a comprehensive modernization of German radiation protection law, which is largely based on Directive 2013/59/Euratom, the provisions of the X-Ray Ordinance have been incorporated into the revised Radiation Protection Ordinance. Among many other measures, contaminated food was withdrawn from the market on a large scale. Parents were strongly advised not to let their children play in sandboxes. Some of the contaminated sand was replaced. In 1989, the Federal Office for Radiation Protection was incorporated into the Ministry of the Environment. On April 30, 2003, a new precautionary radiation protection law was promulgated to implement two EU directives on the health protection of persons against the dangers of ionizing radiation during medical exposure. The protection of workers from optical radiation (infrared radiation (IR), visible light (VIS) and ultraviolet radiation (UV)), which falls under the category of non-ionizing radiation, is regulated by the Ordinance on the Protection of Workers from Artificial Optical Radiation of 19 July 2010. It is based on the EU Directive 2006/25/EC of April 27, 2006. On March 1, 2010, the "Act on the Protection of Humans from Non-Ionizing Radiation" (NiSG), BGBl. I p. 2433, came into force, according to which the use of sunbeds by minors has been prohibited since August 4, 2009, in accordance with § 4 NiSG [Network and Information Systems Security Ordinance – NIS Ordinance] (in German) A new Radiation Protection Act came into force in Germany on October 1, 2017.
The attorney general presented six science witnesses, two more than had testified for the ACLU, presumably on the grounds that quantity made up for evident lack of quality. There would have been more had not a serious case of disappearing witnesses set in as the second week wore on. Dean Kenyon, a biologist from San Francisco State University, fled town after watching the demolition of four of the state's witnesses on day 1 of the second week. And Henry Voss, a computer scientist from California, was rapidly withdrawn at the last minute when, in pretrial deposition, he too began to expound on things satanic and demonical. The Arkansas attorney general apparently threatened to sue Bird after this interference:
=== Bipolar disorder === In a small clinical study, pentazocine, a KOR agonist, rapidly reduced acute manic symptoms in bipolar disorder patients. The therapeutic mechanism is postulated to involve KOR agonist-mediated suppression of excessive dopaminergic signaling in reward pathways and striatal circuits that drive manic hyperactivity and impulsivity. Complete desensitization of KOR renders the receptor unable to gate dopaminergic signaling, thereby lifting the inhibitory constraint and disinhibiting phasic dopamine and norepinephrine release. Temporary KOR sensitization during acute mania may reverse this disinhibition.
Avalglucosidase alfa, sold under the brand name Nexviazyme, is an enzyme replacement therapy medication used for the treatment of glycogen storage disease type II (Pompe disease). The most common side effects include headache, fatigue, diarrhea, nausea, joint pain (arthralgia), dizziness, muscle pain (myalgia), itching (pruritus), vomiting, difficulty breathing (dyspnea), skin redness (erythema), feeling of "pins and needles" (paresthesia) and skin welts (urticaria). Avalglucosidase alfa was approved for medical use in the United States in August 2021, and in the European Union in June 2022.
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.
Epitalon is a synthetic tetrapeptide composed of four amino acids: alanine, glutamate, aspartate, and glycine. It is written as Ala-Glu-Asp-Gly. The free peptide has a molecular weight of about 390 daltons and is normally supplied as a lyophilized powder.