epithalamin is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Last reviewed on 2026-01-21. Where a claim depends on a specific study, the study is described rather than over-claimed.
Material sold for research use varies widely in documented quality. A useful verification package includes a certificate of analysis that states peptide content rather than only net weight, the chromatographic method and column used, and a mass spectrum consistent with the expected mass. Independent testing by a third-party laboratory is occasionally reported. Statements of identity resting only on a supplier label provide little assurance, and the gap between nominal mass and actual peptide content can be substantial once counterions and residual water are counted.
Peptides of this size are generally stable as dry solids but degrade in solution over time. The principal routes are hydrolysis of the peptide backbone and oxidation, with hydrolysis favoured by elevated temperature and extreme pH. Aqueous solutions held at room temperature can show measurable loss of purity within days, while frozen aliquots are considerably more durable. Because the sequence contains neither cysteine nor methionine, oxidation is less of a concern than for many other peptides, but pH control during handling still matters.
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.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Lyophilized solid |
| Solubility | Freely soluble in water | Also dissolves in polar organic solvents |
| Typical storage temperature | −20 °C or below | Sealed, desiccated, protected from light |
| Primary purity assay | Reversed-phase HPLC | Ultraviolet detection near 214 nm |
| Identity confirmation | Mass spectrometry | Electrospray ionization commonly used |
Reference material is normally supplied as a lyophilised powder in a sealed vial. Product literature typically recommends storage at minus twenty degrees Celsius or colder, protected from light and moisture. Freeze-thaw cycling is usually avoided because repeated condensation can introduce water into the vial. Working solutions are commonly prepared fresh, aliquoted, and kept cold for short periods rather than stored at ambient temperature. Labelling the date of opening helps track how long a vial has been in use.
Solubility is high in water, phosphate-buffered saline and normal saline, a pattern that follows from the two acidic residues in the chain. The peptide dissolves poorly in non-polar solvents such as hexane or chloroform. Stock solutions are often prepared in water first and then diluted into the buffer of interest. Because the molecule is small and hydrophilic, filtration through a low-protein-binding membrane is usually straightforward, and visible particulates are uncommon in freshly made solutions.
Identity and purity are established with reversed-phase high-performance liquid chromatography and mass spectrometry. The chromatogram shows the main peak and any truncated or oxidised by-products, while the mass spectrum confirms the expected 390 dalton mass. Amino acid analysis can corroborate composition when a sample's origin is uncertain. Counterion content, particularly residual trifluoroacetate from purification, is frequently reported alongside purity because it shifts the net mass of the solid.
Epitalon is the common name for a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, usually abbreviated AEDG. All four residues are proteinogenic amino acids, and the free peptide has a calculated mass near 390 grams per mole. Because the chain is short and carries no modifications, it is assembled readily by solid-phase synthesis and is distributed mainly as a freeze-dried solid for laboratory work. Catalogue listings use the spellings epitalon, epithalone, and simply AEDG, and the three refer to the same sequence.
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.
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.
The peptide emerged from research carried out in Saint Petersburg from the late 1980s onward, where investigators searched for shorter active fragments of a pineal preparation known as epithalamin. The name epitalon was chosen to reflect that parent extract. Early reports described effects on neuroendocrine markers and on the lifespan of laboratory animals. Much of that work appeared in Russian-language journals, with English translations following later, which affects how readily the original protocols can be assessed by outside groups.
Published studies on epitalon are dominated by a small number of research groups, and independent replication in other laboratories remains limited. Proposed mechanisms include activation of telomerase and modulation of melatonin rhythms, but the evidence for either rests mainly on cell cultures and animal models. Whether the peptide produces comparable effects in humans is an open question, and the absence of large controlled trials means the literature is best read as exploratory rather than settled.
In an exothermic reaction, the temperature in the sample cell increases upon addition of ligand. This causes the feedback power to the sample cell to be decreased (remember: a reference power is applied to the reference cell) in order to maintain an equal temperature between the two cells. In an endothermic reaction, the opposite occurs; the feedback circuit increases the power in order to maintain a constant temperature (isothermal operation). Observations are plotted as the power needed to maintain the reference and the sample cell at an identical temperature against time. As a result, the experimental raw data consists of a series of spikes of heat flow (power), with every spike corresponding to one ligand injection. These heat flow spikes/pulses are integrated with respect to time, giving the total heat exchanged per injection. By integrating each peak from the baseline, the total heat associated with each injection is obtained, including both reaction-specific and non-reaction-related contributions. The pattern of these heat effects as a function of the molar ratio [ligand]/[macromolecule] can then be analyzed to give the thermodynamic parameters of the interaction under study.
Bacterial infections such as mycoplasma, Legionnaires' disease, syphilis, listeriosis, or E. coli. Viral infections such Epstein-Barr virus, cytomegalovirus, mumps, varicella, rubella, adenovirus, HIV, influenza, or hepatitis C. Parasitic infections such as malaria or trypanosomiasis. Other autoimmune diseases such as systemic lupus erythematosus. Certain types of cancers such as lymphoma, chronic lymphocytic leukemia, Waldenström macroglobulinemia, multiple myeloma, and Kaposi sarcoma. In children, cold agglutinin disease is often secondary to an infection, such as Mycoplasma pneumonia, mononucleosis, and HIV.
== Death and race continuation == On March 27, 2012, True failed to return after heading out for a run in the Gila Wilderness, part of the Gila National Forest in southwestern New Mexico. He departed from the Wilderness Lodge in Gila, saying he was going for a 12-mile (19 km) run. A subsequent mountain rescue effort involved three aircraft and at least nine search and rescue teams in off-road vehicles and on horseback, looking across 200,000 acres (81,000 ha) of high desert. Searchers included ultra-runners such as Scott Jurek, Kyle Skaggs, Timothy Olson, and many athletes and friends who had participated in the 51 mile Copper Canyon Ultra Marathon. On March 31, True was found dead with his legs dangling in a stream. The local sheriff said there were "no obvious signs of trauma", although True had scrapes and abrasions on his hands, arms, and knees, suggesting a fall. His remains were removed by horseback. Because of difficult terrain and remote location, the recovery was not completed until April 1. An autopsy was inconclusive with respect to the actual cause of death, revealing, however, that True was suffering from idiopathic cardiomyopathy, which had caused the left ventricle of his heart to become enlarged.
=== Functionalization === Many properties of nanoparticles, notably stability, solubility, and chemical or biological activity, can be radically altered by coating them with various substances — a process called functionalization. Functionalized nanomaterial-based catalysts can be used for catalysis of many known organic reactions. For example, suspensions of graphene particles can be stabilized by functionalization with gallic acid groups. For biological applications, the surface coating should be polar to give high aqueous solubility and prevent nanoparticle aggregation. In serum or on the cell surface, highly charged coatings promote non-specific binding, whereas polyethylene glycol linked to terminal hydroxyl or methoxy groups repel non-specific interactions. By the immobilization of thiol groups on the surface of nanoparticles or by coating them with thiomers high (muco)adhesive and cellular uptake enhancing properties can be introduced. Nanoparticles can be linked to biological molecules that can act as address tags, directing them to specific sites within the body specific organelles within the cell, or causing them to follow specifically the movement of individual protein or RNA molecules in living cells. Common address tags are monoclonal antibodies, aptamers, streptavidin, or peptides. These targeting agents should ideally be covalently linked to the nanoparticle and should be present in a controlled number per nanoparticle.
Sources: en.wikipedia.org
molar concentration Also molarity, amount concentration, or substance concentration. A measure of the concentration of a chemical species, especially of a solute in a solution, in terms of the amount of the species per unit volume of solution. Molarity is typically expressed in units of moles per litre (mol/L); a solution with a concentration of exactly 1 mol/L is commonly said to be 1 molar, abbreviated 1 M. Contrast molality.
During the Great Migration, millions of African Americans left the rural South for urban areas in the North. Alaska was purchased from Russia in 1867. The Compromise of 1877 is generally considered the end of the Reconstruction era, as it resolved the electoral crisis following the 1876 presidential election and led President Rutherford B. Hayes to reduce the role of federal troops in the South. Immediately, the Redeemers began evicting the Carpetbaggers and quickly regained local control of Southern politics in the name of white supremacy. African Americans endured a period of heightened, overt racism following Reconstruction, a time often considered the nadir of American race relations. A series of Supreme Court decisions, including Plessy v. Ferguson, emptied the Fourteenth and Fifteenth Amendments of their force, allowing Jim Crow laws in the South to remain unchecked, sundown towns in the Midwest, and segregation in communities across the country, which would be reinforced in part by the policy of redlining later adopted by the federal Home Owners' Loan Corporation. An explosion of technological advancement, accompanied by the exploitation of cheap immigrant labor, led to rapid economic expansion during the Gilded Age of the late 19th century. It continued into the early 20th, when the United States already outpaced the economies of Britain, France, and Germany combined. Tycoons led the nation's expansion in the railroad, petroleum, and steel industries, as the United States emerged as a pioneer of the automotive industry.
== Patents == US patent 3987302, George S. Hurst, Marvin G. Payne, Edward B. Wagner, "Resonance ionization for analytical spectroscopy", issued October 19, 1976 US patent 4,442,354, Hurst, G. Samuel, James E. Parks, James E. & Schmitt, Harold W, "Method of analyzing for a component in a sample", issued April 10, 1984
Sources: en.wikipedia.org
The powder is normally kept at −20 °C or below in a sealed, moisture-protected container. Letting the vial reach room temperature before opening helps prevent condensation on the contents.
Reversed-phase HPLC with ultraviolet detection is the usual approach, often paired with mass spectrometry. Together the two methods address both chromatographic purity and molecular identity.
Differences arise from the analytical method, the detection wavelength, and whether the number refers to the peptide or to total powder mass. Counterion and water content can lower the actual peptide fraction considerably.
It is a four-amino-acid peptide built from alanine, glutamate, aspartate and glycine in that order. Its formula is C14H22N4O9, and it is made by chemical synthesis rather than extracted from tissue. The synthetic peptide is a single defined molecule, unlike the pineal extracts it is often compared with.