If you have been reading about aspartimide 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 2026-08-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
Because epitalon has no pharmacopoeial monograph, quality assessment depends on supplier documentation and independent testing. Certificates of analysis typically report a purity figure from a single chromatographic run, a measured mass and sometimes an appearance description, but methods and acceptance criteria are not harmonised across vendors. Third-party laboratories can repeat identity and purity measurements, and mismatches between labelled and measured peptide content have been described for research peptides generally. What constitutes adequate identity confirmation for a molecule of this size stays an open question, since mass agreement alone does not separate closely related sequences.
Identity testing for epitalon relies on reversed-phase high-performance liquid chromatography for purity and mass spectrometry for mass confirmation. Because the sequence contains no tryptophan or tyrosine, ultraviolet detection at 280 nanometres is insensitive, so chromatographic methods usually monitor absorbance near 214 nanometres, where the peptide backbone absorbs. Electrospray ionisation or matrix-assisted laser desorption/ionisation then checks the intact mass against the expected value near 390 daltons. Peptide mapping or amino acid analysis after acid hydrolysis can supplement these measurements, although such confirmatory work is seldom reported on commercial certificates of analysis.
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.
Epitalon is a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, commonly abbreviated AEDG. It was designed at the St. Petersburg Institute of Bioregulation and Gerontology as a short, chemically defined analogue of epithalamin, a fraction obtained from bovine pineal tissue. Small peptide bioregulators of this type formed a long-running line of work there from the 1980s onward. Because the molecule is produced by solid-phase synthesis rather than extraction, its composition is exact and its purity can be measured directly.
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.
| Property | Value | Notes |
|---|---|---|
| Analytical method | Reversed-phase HPLC | Purity determination, typically 214 nm |
| Mass confirmation | ESI or MALDI mass spectrometry | Compared with mass near 390 Da |
| Common synonyms | Epitalon, epithalon, AEDG | Naming differs between suppliers |
| Storage temperature | −20 °C or lower | Lyophilised powder, kept desiccated |
| Solution stability | Limited in neutral aqueous buffer | Aspartimide and hydrolysis pathways |
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 molecule is a short, linear, hydrophilic peptide that dissolves readily in water or aqueous buffer. Its principal chemical liabilities are hydrolytic rather than oxidative, since it contains no cysteine, methionine, or tryptophan residues. The aspartate–glycine step is a recognised site for aspartimide formation under mildly acidic or basic conditions, generating isoaspartate and succinimide-related products over time. Desiccated lyophilised powder held at −20 °C is comparatively stable, whereas dilute solutions degrade faster and are best frozen as single-use aliquots rather than thawed repeatedly.
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.
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.
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.
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.
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Combinatorial chemistry involves simultaneously synthesizing a large number of related compounds for high-throughput analysis. Chemical biologists are able to use principles from combinatorial chemistry in synthesizing active drug compounds and maximizing screening efficiency. Similarly, these principles can be used in areas of agriculture and food research, specifically in the syntheses of unnatural products and in generating novel enzyme inhibitors.
Tilidine is used in the form of hydrochloride or phosphate salt. In Germany, tilidine is available in a fixed combination with naloxone for oral administration (Valoron N and generics); the mixture of naloxone is claimed to lower the abuse liability of the opioid analgesic. This is so that if people take the medication orally (which is the way they are meant to) the opioid blocker, naloxone, has minimal effects on them but if they inject it the naloxone becomes bioavailable and hence antagonizes the effects of the tilidine producing withdrawal effects. In Switzerland the original Valoron brand with only tilidine and no naloxone is also available. As well as its use as an analgesic, tilidine is also commonly used in Germany for treatment of restless legs syndrome. The reverse ester is also known and is also a prodrug. Tilidine explicitly without Naloxone is a controlled substance in most countries, listed in the German BtMG, Austrian SMG, and in the USA under the Controlled Substances Act as ACSCN 9750 as a Narcotic under Schedule I, with an annual aggregate manufacturing quota of 10 grams in 2014. It is used as the hydrochloride (free base conversion ratio 0.882) and HCl hemihydrate (0.858).
=== Graft-versus-host disease === Due to its immunosuppressant activity, rapamycin has been assessed as prophylaxis or treatment agent of graft-versus-host disease (GVHD), a complication of hematopoietic stem cell transplantation. While contrasted results were obtained in clinical trials, pre-clinical studies have shown that rapamycin can mitigate GVHD by increasing the proliferation of regulatory T cells, inhibiting cytotoxic T cells and lowering the differentiation of effector T cells.
Sources: en.wikipedia.org
=== Response to Russia and China === On March 6, 2026, Hegseth dismissed reports from CBS News and other outlets citing U.S. officials who claimed Russia was providing intelligence to Iran regarding American positions in the Middle East. Hegseth stated, "We're putting the other guys in danger, and that's our job. So we're not concerned about that. ... But the only ones that need to be worried right now are Iranians that think they're gonna live." However, four days later, he warned Russia against intervention following further reports of its alleged assistance in targeting U.S. military assets in the Middle East. While Hegseth initially dismissed China as "irrelevant" to the conflict in early March 2026, his stance shifted by the end of the month following reports of alleged technological support to Tehran. On March 31, he stated the U.S. was "addressing and mitigating" Chinese involvement. However, on April 16, Hegseth announced that Beijing had provided high-level assurances to the White House that it would not send weapons to Iran, citing direct communication between President Trump and Xi Jinping ahead of a planned summit in Beijing.
=== Regulations === Worldwide, most polities have no laws about circumcision of males, with religious infant circumcision legal in every country. A few countries have passed legislation on the procedure: Germany allows routine circumcision, while non-religious routine neonatal circumcision is regulated in South Africa and Sweden. No major medical organization recommends circumcising all males, and no major medical organization recommends banning the procedure. In the academic literature, there is general agreement among both supporters and opponents of the practice that an outright ban would be predominately ineffective and "harmful". A consensus to keep the procedure within the purview of medical professionals is found across all major medical organizations, which advise medical professionals to yield to some degree to parental preferences in their decision to circumcise. The Royal Dutch Medical Association, which expresses some of the strongest opposition to routine neonatal circumcision, argues that while there are valid reasons for banning it, doing so could lead parents who insist on it to turn to poorly trained practitioners instead of medical professionals. During the 2010s, several right-wing nationalist parties prominently called for the banning of circumcision. Randi Gressgård, Researcher at the Centre for Women's and Gender Research (SKOK) at the University of Bergen, argued that politicians that supported Norway's proposed circumcision ban debated circumcision in a manner which constituted "ethnocentrism".
=== Florists' attitudes === Many traditional retail florists have a deep-rooted disdain for modern wire services. This comes from the perception that companies such as FTD, 1800flowers, From You Flowers and Teleflora take floral orders away from the local business and extract excessive commission. FTD was formerly a co-op, owned by its member florists. In 1994 the board of directors made the decision to sell the co-op to Perry Capital. The revenue from the sale was disbursed amongst the member florists, more senior florists being paid substantially more than the more junior florists. At this point FTD became a for-profit company.
A rapidly increasing list of production techniques have been developed to enable graphene's use in commercial applications. Isolated 2D crystals cannot be grown via chemical synthesis beyond small sizes even in principle, because the rapid growth of phonon density with increasing lateral size forces 2D crystallites to bend into the third dimension. In all cases, graphene must bond to a substrate to retain its two-dimensional shape.
== Health hazards == Several chemical substances have been found to be effective in skin whitening, but some have been proven or suspected to be toxic. This includes compounds containing mercury, which can cause neurological and kidney problems. These products also contain collagen, which can be harmful to the skin. It is present in day creams and beauty masks. Collagen is an insoluble fibrous protein that is too large to penetrate the skin, thus it can clog pores. The use of these products can be hazardous to health, potentially causing acne, stretch marks, skin cancer, hypertension, or diabetes, especially when the product contains hydroquinone, mercury, cortisone, or vitamin A. Allergic reactions or undesirable effects, such as uneven hyperpigmentation or patchy depigmentation, can also occur. Among the ingredients, hydroquinone is also commonly found and is responsible for multiple side effects. It can interfere with the reagents used in capillary blood glucose meters, artificially raising blood glucose levels. In 1997, in Paris, the French police dismantled a network involved in the illegal trafficking of skin lightening products, primarily targeting Congolese migrants. Such products represent a significant market despite their health risks. Users resort to preparations containing mercury or bleach, or products containing corticosteroids or quinine. The Saint-Louis Hospital in Paris had to establish a specialized department to deal with the skin disorders caused by skin bleaching.
Sources: en.wikipedia.org
The missing technique that made radar practical was the use of pulses to determine range by measuring the time between the transmission of the signal and reception of the reflected signal. This would allow a single station to measure angle and range simultaneously. In 1924, two researchers at the Naval Research Laboratory in the United States, Merle Tuve and Gregory Briet, decided to recreate Appleton's experiment using timed pulsed signals instead of the changing wavelengths. The application of this technique to a detection system was not lost on those working in the field, and such a system was prototyped by W. A. S. Butement and P. E. Pollard of the British Signals Experimental Establishment (SEE) in 1931. The War Office proved uninterested in the concept and the development remained little known outside SEE.
In an exclusive interview filmed at Howe's studio within the historic tower, the lead concept artist behind Peter Jackson's The Lord of the Rings and The Hobbit film trilogies endorsed augmented reality and the Cybel'Art protocol as the future of fantasy art, declaring: "Fantasy is a profession of the future through augmented reality and initiatives like yours."
The most common cause of ketoacidosis is a deficiency of insulin in type 1 diabetes or late-stage type 2 diabetes. This is called diabetic ketoacidosis and is characterized by hyperglycemia, dehydration and metabolic acidosis. Other electrolyte disturbances such as hyperkalemia and hyponatremia may also be present. A lack of insulin in the bloodstream allows unregulated fatty acid release from adipose tissue which increases fatty acid oxidation to acetyl CoA, some of which is diverted to ketogenesis. This raises ketone levels significantly above what is seen in normal physiology.
Azoospermia factor (AZF) is one of several proteins or their genes, which are coded from the AZF region on the human male Y chromosome. Deletions in this region are associated with inability to produce sperm. Subregions within the AZF region are AZFa (sometimes AZF1), AZFb and AZFc (together referred to as AZF2). AZF microdeletions are one of the major causes of male infertility for azoospermia (complete absence of sperm in the ejaculate) and severe oligozoospermia (less than 5 million spermatozoa in the ejaculate) males. AZF is the term used by the HUGO Gene Nomenclature Committee. Of the 15% of couples who are affected by infertility, 50% of those cases are due to the male partner. 15-30% of male factor infertility cases can be correlated with genetic abnormalities. One of the most commonly identified genetic abnormalities in male factor infertility are microdeletions on the long arm of the Y chromosome (Yq), specifically at a region known as the azoospermic factor (AZF) region. In certain circumstances, men with AZF mutations can turn to assisted reproductive technologies (ART), such as intracytoplasmic sperm injection (ICSI), to help them overcome their suboptimal sperm quality. However, it may be more important for clinicians to screen for Yq microdeletions, due to a growing body of evidence that AZF microdeletions have the capability to be vertically transmitted to male offspring. Minor et al. demonstrated that an AZFc mutation was vertically transmitted over three generations via fathers receiving reproductive assistance through ICSI.
GB patent 1472793, John B. Glen; Roger James & Bob-James Munroe, "Pharmaceutical Compositions", published 4 May 1977, assigned to Imperial Chemical Industries Ltd Archived 5 June 2021 at the Wayback Machine
Sources: en.wikipedia.org
The molecule lacks aromatic residues, so it absorbs weakly near 280 nanometres, the wavelength applied to many other peptides. The peptide bond absorbs strongly below 220 nanometres, making 214 nanometres a practical compromise. Gradient methods must therefore use mobile phases with low ultraviolet absorbance to keep the baseline clean.
Neutral and slightly basic aqueous conditions promote aspartimide formation at the aspartate-glycine step, often followed by deamidation. Elevated temperature and repeated freeze-thaw cycles accelerate the loss. Acidic solutions and dry lyophilised powder are comparatively stable over short periods.
No monograph exists in the United States Pharmacopeia or the European Pharmacopoeia, and no widely distributed certified reference standard is available. Purity and identity therefore rest on supplier methods that are not harmonised. This absence is the main reason reported purities are difficult to compare between sources.
No. Epithalamin is a peptide-containing extract of bovine pineal glands, while epitalon is a single synthetic tetrapeptide. The extract contains many peptides and other tissue components, so its composition varies between batches in ways that a synthesised sequence does not.