This is a working overview of Lyophilized powder, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-04-26. Anything still debated is marked as such rather than presented as settled.
Literature searches for this compound must account for several spelling variants. Indexing databases contain epitalon, epithalon, epithalone, and AEDG, and relevant records are scattered across Russian-language and English-language journals that do not consistently cross-cite. Early publications describe the parent extract as a mixture of many peptides, whereas later work addresses the single synthetic tetrapeptide. That shift in nomenclature complicates comparison between studies, because extract data and tetrapeptide data are sometimes cited interchangeably. A search strategy omitting the alternate spellings will return an incomplete set of references.
Reported biological findings come mainly from cell culture and rodent experiments. Those studies describe changes in telomerase catalytic subunit expression, melatonin rhythm amplitude, and antioxidant enzyme activity after peptide exposure. Human data are sparse and consist of small trials with limited blinding and inconsistent endpoints. The proposed mechanisms remain hypotheses rather than established facts, and there is no consensus on whether effects observed in animals carry over to people. Independent replication outside the original research groups is limited, which is a recognised gap in the published literature.
The parent extract epithalamin was characterised as a low-molecular-weight fraction of pineal tissue rather than a single defined chemical entity. Researchers fractionated it and tested successive fragments for activity, a screening approach typical of peptide discovery work in that era. Epitalon emerged from that process as one of the shorter sequences of interest. Because the original extract was never fully resolved into individual components, claims about which constituent drives a given effect rest on inference. This distinction matters when reading older reports that attribute extract observations to the tetrapeptide itself.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic tetrapeptide | Four amino acid residues |
| Residue sequence | Ala-Glu-Asp-Gly | Abbreviated AEDG |
| Approximate mass | 390.35 Da | Monoisotopic, free base form |
| Parent preparation | Epithalamin extract | Derived from pineal tissue |
| Common spelling variants | Epithalon, epithalone, AEDG | Affects literature retrieval |
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.
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.
Storage recommendations center on limiting moisture, heat, and light. The dry powder is generally kept at minus 20 degrees Celsius, and some suppliers recommend minus 80 degrees for long-term archival. Once dissolved, solutions are usually aliquoted and frozen to avoid repeated freeze-thaw cycles, which can promote aggregation or degradation. Aqueous stability depends on pH and concentration, and buffered saline is often preferred over plain water for biological work. Stability data specific to epitalon remain limited, so general peptide-handling practices are applied by analogy rather than from product-specific validation.
Epitalon is a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, abbreviated AEDG. Its molecular formula is C14H22N4O9 and its calculated monoisotopic mass is approximately 390.35 daltons. The compound does not occur naturally as a free peptide; it is produced by solid-phase peptide synthesis. Because it contains two acidic residues and no basic residues, the neutral form carries a net negative charge at physiological pH. This charge profile influences how the peptide behaves in solution and during chromatographic analysis.
Laboratory-grade epitalon is typically supplied as a lyophilized powder. Purity is commonly assessed with reverse-phase high-performance liquid chromatography, often paired with mass spectrometry to confirm molecular identity. Amino acid analysis and peptide mapping can provide additional confirmation of sequence. Certificates of analysis for research materials frequently report purity above 95 percent, although the methods behind such figures vary between suppliers. The absence of a pharmacopeial monograph means that no single standardized assay defines the compound, so reported results depend on the analytical protocol chosen.
Studies have shown that common misconceptions about the effectiveness and necessity of antibiotics to treat common mild illnesses contribute to their overuse. Important to the conversation of antibiotic use is the veterinary medical system. Veterinary oversight is required by law for all medically important antibiotics. Veterinarians use the Pharmacokinetic/pharmacodynamic model (PK/PD) approach to ensuring that the correct dose of the drug is delivered to the correct place at the correct timing.
The 550-metre (1,804 ft) Crystal Palace pneumatic railway was exhibited at the Crystal Palace in 1864. This was a prototype for a proposed Waterloo and Whitehall Railway that would have run under the River Thames linking Waterloo and Charing Cross. Digging commenced in 1865 but was halted in 1868 due to financial problems. In 1867 at the American Institute Fair in New York, Alfred Ely Beach demonstrated a 100-foot (30 m) long, 6-foot (1.8 m) diameter pipe that was capable of moving 12 passengers plus a conductor. One year after New York City's first-ever elevated rail line went into service; in 1869, the Beach Pneumatic Transit Company of New York secretly constructed a 312-foot (95 m) long, 8.9-foot (2.7 m) diameter pneumatic subway line under Broadway, to demonstrate the possibilities of the new transport mode. The line only operated for a few months, closing after Beach was unsuccessful in getting permission to extend it – Boss Tweed, a corrupt influential politician, did not want it to go ahead as he was intending to personally invest into competing schemes for an elevated rail line.
Tiagabine, sold under the brand name Gabitril, is an anticonvulsant medication which is used in the treatment of epilepsy. It is also used off-label in the treatment of insomnia and anxiety disorders. However, off-label use is discouraged as the drug has been associated with new-onset seizures in people without epilepsy. Tiagabine is taken orally. Side effects of tiagabine include dizziness, asthenia, non-specific nervousness, muscle tremors, diarrhea, depression, and emotional lability. The drug acts as a selective GABA transporter 1 (GAT-1) blocker or GABA reuptake inhibitor, and hence acts as an indirect GABA receptor agonist, increasing GABAergic signaling in the brain. It may increase activation of both GABAA and GABAB receptors. The effects of tiagabine on sleep resemble those of GABAA receptor agonists like gaboxadol and muscimol, primarily enhancing slow wave sleep, and differ from those of GABAA receptor positive allosteric modulators like benzodiazepines and Z drugs. The drug's elimination half-life is 4.5 to 9 hours, but can be shorter in people taking enzyme-inducing anticonvulsants. Tiagabine was discovered in 1988 and was introduced for medical use in 1997. Generic formulations have become available. The drug is not a controlled substance in the United States.
== External links == Drug Interactions: What You Should Know. U.S. Food and Drug Administration, Center for Drug Evaluation and Research, September 2013 COVID 19 Drug interaction check tool University of Liverpool
Sources: en.wikipedia.org
=== In popular culture === The movie A Civil Action, starring John Travolta, was based on the Grace groundwater contamination lawsuits in Woburn, Massachusetts. The PBS television show P.O.V., which highlights independent films, in August 2007 premiered the movie Libby, Montana which documents the thousands of people in Libby, Montana, that have been exposed to and are suffering the effects of asbestos exposure. The show also discusses the criminal indictments of many Grace executives for covering up asbestos related illnesses and deaths. PBS also aired Dust to Dust, a documentary produced by Michael Brown Productions, Inc. in 2002. Dust to Dust reports on the more than 200 people who have died from asbestos exposure in Libby, Montana. The film focuses on the plights of several of these individuals and the damage done over almost 30 years while the mine was operated by W. R. Grace. NPR aired a piece on All Things Considered discussing the criminal charges against W. R. Grace. A U.S. attorney general alleges that the company and managers of the mine in Libby, Montana, knew about the dangers of the asbestos they were dumping into the air for over 20 years. On February 19, 2008, the NPR-produced radio show Here and Now broadcast a story about the film Libby, Montana, which details the asbestos contamination in the town of that name. On April 22, 2009, the television and radio program Democracy Now! broadcast two segments on the trial of W. R. Grace and some of its employees related to the asbestos contamination in Libby, Montana.
The Spanish American wars of independence (Spanish: Guerras de independencia hispanoamericanas) were a series of conflicts across the Spanish Empire in the early 19th century. They began shortly after the outbreak of the Peninsular War and formed part of the broader Napoleonic Wars. The process unfolded in two main phases. First, the Spanish Monarchy broke up, beginning in Spain in 1808 with the invasion by the French Empire, the Spanish uprising against the Bonapartes, the vacancy of the throne, and the emergence of juntas later replicated in America. This unfolded as it did because the monarchy's basic cellular structure was the cabildo (town council, or ayuntamiento). Second, attempts at reconstruction failed and became a war in their own right: Cádiz sought a pan-Hispanic state, Ferdinand VII sought to restore the Crown returned to him by Napoleon, and in the Americas Bolívar, Iturbide and others tried to build large federations or empires. The result was the fragmentation of the Hispanic world into multiple states that largely reconstituted the old Spanish administrative boundaries under uti possidetis. The conflicts were multilateral, involving factions grouped into two camps: Royalists, who favoured continued Spanish rule, and Patriots, who supported independent monarchies or republics separate from Spain and from one another. They led to the independence of most of Spanish America and, through Balkanization, to Hispanic America. Defined strictly by military campaigns, they ran from the 1809 Battle of Chacaltaya (Bolivia) to the 1829 Battle of Tampico (Mexico).
The first ionisation energy of an element or molecule is the energy required to move the most loosely held electron from one mole of gaseous atoms of the element or molecules to form one mole of gaseous ions with electric charge +1. The factors affecting the first ionisation energy are the nuclear charge, the amount of shielding by the inner electrons and the distance from the most loosely held electron from the nucleus, which is always an outer electron in main group elements. The first two factors change the effective nuclear charge the most loosely held electron feels. Since the outermost electron of alkali metals always feels the same effective nuclear charge (+1), the only factor which affects the first ionisation energy is the distance from the outermost electron to the nucleus. Since this distance increases down the group, the outermost electron feels less attraction from the nucleus and thus the first ionisation energy decreases. This trend is broken in francium due to the relativistic stabilisation and contraction of the 7s orbital, bringing francium's valence electron closer to the nucleus than would be expected from non-relativistic calculations. This makes francium's outermost electron feel more attraction from the nucleus, increasing its first ionisation energy slightly beyond that of caesium. The second ionisation energy of the alkali metals is much higher than the first as the second-most loosely held electron is part of a fully filled electron shell and is thus difficult to remove.
from Piedmontese beef) has a place on the specialist market due to its high palatability and tenderness, at least for purebred myostatin-deficient strains the expenses and (especially in cattle) necessity of veterinary supervision place them at a disadvantage in the bulk market.
== Animal tissue == Animal tissues are grouped into four basic types: connective, muscle, nervous, and epithelial. Organs are formed by the functional grouping together of two or more different tissue types. While most animals can generally be considered to contain the four tissue types, the manifestation of these tissues can differ depending on the type of organism. For example, the origin of the cells comprising a particular tissue type may differ developmentally for different classifications of animals. Tissue appeared for the first time in the diploblasts, but modern forms only appeared in triploblasts. The epithelium in all animals is derived from the ectoderm and endoderm (or their precursor in sponges), with a small contribution from the mesoderm, forming the endothelium, a specialized type of epithelium that composes the vasculature. By contrast, a true epithelial tissue is present only in a single layer of cells held together via occluding junctions called tight junctions, to create a selectively permeable barrier. This tissue covers all organismal surfaces that come in contact with the external environment such as the skin, the airways, and the digestive tract. It serves functions of protection, secretion, and absorption, and is separated from other tissues below by a basal lamina. The connective tissue and the muscular are derived from the mesoderm. The nervous tissue is derived from the ectoderm.
Sources: en.wikipedia.org
It is based on epithalamin, a peptide-rich preparation obtained from pineal gland tissue and studied in the former Soviet Union. Researchers later identified the tetrapeptide AEDG as a constituent fragment of that material. Modern supplies are produced by chemical synthesis rather than tissue extraction.
No. Epithalamin is a heterogeneous extract containing many peptides, while epitalon is a single synthesised tetrapeptide. Publications sometimes treat findings from the two as equivalent, which is a common source of confusion. Their compositions differ and they are not interchangeable in analytical terms.
Most published work uses cell cultures or rodents because those models are faster and less costly to run. The few human trials that have been reported are small, and several lack control groups or blinding. This restricts what can reasonably be concluded about effects in people.
The dry powder is typically held at -20 degrees Celsius or lower, protected from light and moisture. Allowing a sealed vial to reach room temperature before opening reduces condensation on its contents. Conditions stated on a supplier certificate of analysis take precedence over general guidance.