tetrapeptide raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-01-29 and is reviewed periodically as new material appears.
Documentation accompanying research peptides usually includes a certificate of analysis listing the batch number, purity figure, and test methods applied. Buyers comparing suppliers should check whether the reported purity refers to chromatographic area or to a mass-balance calculation, because the two are not equivalent. Counter-ion content, residual solvents, and water content are sometimes omitted from such certificates even though they affect the actual peptide mass present. Independent verification through a second laboratory is the most direct way to confirm that a supplied material matches its label.
Purity assessment of peptide reagents normally relies on reversed-phase high-performance liquid chromatography. A gradient of acetonitrile in water with trifluoroacetic acid, paired with a C18 stationary phase, separates the target tetrapeptide from truncated sequences and deletion analogues. Detection at 214 nanometres exploits absorbance of the peptide backbone, since the molecule contains no aromatic residue. Results are expressed as a percentage of total peak area. Values above ninety-five percent are typical for research-grade material, although reporting conventions vary between suppliers.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Freeze-dried solid |
| Solubility class | Freely soluble in water | Aqueous buffers also suitable |
| Typical storage temperature | Minus 20 degrees Celsius or colder | Desiccated and light protected |
| Typical analytical method | RP-HPLC with UV detection | 214 nm on C18 column |
| Identity confirmation | Electrospray mass spectrometry | Sequence verified separately |
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.
Laboratory handling begins with dissolution of the lyophilized powder in water or a suitable aqueous buffer. The dry solid is the more stable form, so stock solutions are generally prepared only when required and kept cold afterwards. Repeated freezing and thawing of a solution is avoided because it encourages aggregation and gradual loss of the intact chain. Diluents and containers are selected to limit adsorption of a short peptide onto plastic surfaces and to reduce microbial growth in aqueous preparations.
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.
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.
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.
Human data are limited to small studies, often without the randomization, blinding, or control groups expected in contemporary clinical research. Reported outcomes have included changes in melatonin levels, immune markers, and subjective measures, but sample sizes were generally too small to support firm conclusions. Some reviews treat the peptide as promising while noting methodological weaknesses; others question whether the observed effects are specific. The compound is frequently discussed in longevity-focused communities, where enthusiasm often outpaces the published evidence. Separating established findings from speculation is therefore important when reading summaries of this research.
Epitalon emerged from research conducted in Saint Petersburg by Vladimir Khavinson and colleagues, who studied short peptides as potential regulators of aging. The work built on epithalamin, a pineal gland extract reported to influence neuroendocrine function. Epitalon was designed as a synthetic counterpart with a defined sequence, allowing reproducible experiments that extracts could not support. Early publications described effects on melatonin rhythms and lifespan in animal models. These findings circulated mainly in Russian-language journals during the 1990s, which limited their visibility among English-speaking researchers.
The most widely cited claim is that epitalon activates telomerase and thereby extends telomere length. Supporting evidence comes largely from cultured human cells, where treatment was associated with increased telomerase activity and delayed replicative senescence. Telomerase activation is a biologically consequential effect, since the enzyme is largely silenced in most somatic cells. However, the route by which a short peptide would reach and act on the enzyme's regulatory machinery has not been established. Independent replication in human trials is scarce, so the link between cell-culture observations and whole-body aging remains an open question.
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.
Discussions in the literature often conflate three distinct entities: the pineal extract epithalamin, the isolated tetrapeptide AEDG, and commercial preparations sold under similar names. Reviews citing older Russian-language studies sometimes omit detail on purity, route of administration and control groups, which makes cross-study comparison difficult. Researchers working with the compound generally note the need for independent replication, standardized enzyme assays, and clearer reporting of peptide identity. These caveats are relevant when weighing claims that appear in secondary sources rather than in primary reports.
（TG:@pojiaai）Epitalon is a synthetic linear tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, abbreviated AEDG. It emerged from work on epithalamin, a peptide fraction prepared from bovine pineal tissue, and was designed as a short, chemically defined analogue of that extract. Early publications came mainly from Russian laboratories studying pineal peptides and aging-related endpoints. The compound appears in the literature under several spellings, including epithalon and epithalone, which complicates systematic searching. Its small size makes solid-phase assembly and routine analytical characterization straightforward.
Study and case report form (CRF) design and metadata definition Central or site-based data entry with edit checks, derivations, and discrepancy management Batch loading and standardized extracts for analysis and reporting Medical thesaurus management for coding adverse events, medical history, and medications Laboratory data management with demographic-aware reference ranges and result flagging
=== Other common diseases === EpiVacCorona, a peptide-based vaccine against COVID-19. IC41 is a peptide vaccine candidate against the Hepatitis C virus. It consists of five synthetic peptides along with the synthetic adjuvant called poly-l-arginine. Multimeric-001 is the most efficient peptide vaccine candidate against influenza. It contains B- and T-cell epitopes from Hemagglutinin. Matrix I and nucleoprotein are combined into a single recombinantly-expressed polypeptide. Alzheimer peptide vaccines: CAD106, UB311, Lu, AF20513, ABvac40, ACI-35, AADvac-1.
== Side effects == Nausea, ejaculation failure, insomnia, diarrhea, dry mouth, somnolence, dizziness, tremor, headache, excessive sweating, fatigue, restless legs syndrome and decreased libido are the common adverse effects associated with sertraline with the greatest difference from placebo. Those that most often result in interruption of the treatment are nausea, diarrhea, and insomnia. The incidence of diarrhea is higher with sertraline – especially when prescribed at higher doses – in comparison with other SSRIs. Over more than six months of sertraline therapy for depression, people showed no significant weight increase. A 30-month-long treatment with sertraline for OCD also resulted in no significant weight gain. Although the difference did not reach statistical significance, the average weight gain was lower for fluoxetine (1%) but higher for citalopram, fluvoxamine and paroxetine (2.5%). Of the sertraline group, 4.5% gained a large amount of weight (defined as more than 7% gain). This result compares favorably with placebo, where, according to the literature, 3–6% of patients gained more than 7% of their initial weight. The large weight gain was observed only among female members of the sertraline group; the significance of this finding is unclear because of the small size of the group. Over a two-week treatment of healthy volunteers, sertraline slightly improved verbal fluency but did not affect word learning, short-term memory, vigilance, flicker fusion time, choice reaction time, memory span, or psychomotor coordination.
== Medical use == According to phase III randomized trials, a cangrelor–clopidogrel combination is safe and has been found to be more effective than standard clopidogrel treatment at reducing ischemic events in the heart, without increasing major bleeding in the treatment of stenotic coronary arteries. The advantages of this drug combination are most prominent in patients with myocardial infarction. Available antiplatelet drugs have delayed onset and offset of action. Since cangrelor's effects are immediate and quickly reversed, it is a more desirable drug for elective treatment of stenotic coronary arteries, high risk acute coronary syndromes treated with immediate coronary stenting, and for bridging those surgery patients who require P2Y12 inhibition. Evidence regarding cangrelor therapy is limited by the lack studies assessing cangrelor administration in conjunction with either prasugrel or ticagrelor. Cangrelor been approved for adults undergoing percutaneous coronary intervention (PCI).
==== Alzheimer's Disease ==== Alterations in AMPAR trafficking and function have been observed in Alzheimer's disease models. Dysregulation of the Q/R editing site of the GluA2 subunit affects calcium permeability, influencing dendritic spine morphology and contributing to neurodegeneration and memory deficits.
Sources: en.wikipedia.org
Chromosome 3 open reading frame 5 (C3orf52), also known as TTMP or TPA-Induced Transmembrane Protein (accession: NP_078892), is an uncharacterized protein encoded in humans by the C3orf52 gene. C3orf52 is located on the plus strand of chromosome 3, at gene locus q.13.2. C3orf52 encodes a transmembrane protein which is believed to be responsible for regulating some aspect of epithelial tissue and evidence supports a theory of C3orf52 acting in some capacity to impact hair loss in humans due to interactions with lysophosphatidic acid production required for hair follicle formation.
Australian Football Hall of Fame (inducted 2011) Essendon Football Club Team of the Century (half-forward flank) Champions of Essendon: no. 3 Essendon captain: 1998–2005 Norm Smith Medal: 2000 Brownlow Medal: 1996 Australian Football Media Association Player of the Year: 1996 5× All-Australian team: 1995, 1996, 2000, 2001, 2003 5× Crichton Medal: 1994, 1995, 1996, 2003, 2007 2× Essendon leading goalkicker: 1995, 1996 Jim Stynes Medal: 2000 2× Australia representative honours in international rules football: 2000 (c), 2004 3× Anzac Medal: 2000, 2003, 2004 Yiooken Award: 2007 AFL Rising Star nominee: 1993
When medications do not include specific disposal instructions, patients should not flush medications in the toilet, but instead use medication take-back programs to reduce the amount of pharmaceutical waste in sewage and landfills. If no take-back programs are available, prescription drugs can be discarded in household trash after they are crushed or dissolved and then mixed in a separate container or sealable bag with undesirable substances like cat litter or other unappealing material (to discourage consumption).
The hypothesized existence of an RNA world does not exclude a "Pre-RNA world", where a metabolic system based on a different nucleic acid is proposed to pre-date RNA. A candidate nucleic acid is peptide nucleic acid (PNA), which uses simple peptide bonds to link nucleobases. An alternative—or complementary—theory of RNA origin is proposed in the PAH world hypothesis, whereby polycyclic aromatic hydrocarbons (PAHs) mediate the synthesis of RNA molecules. PAHs are the most common and abundant of the known polyatomic molecules in the visible Universe and are a likely constituent of the primordial sea. PAHs and fullerenes (also implicated in the origin of life) have been detected in nebulae. Some of the difficulties of producing the precursors on earth are bypassed by another alternative or complementary theory for their origin, panspermia. It discusses the possibility that the earliest life on this planet was carried here from somewhere else in the galaxy, possibly on meteorites similar to the Murchison meteorite. Sugar molecules, including ribose, have been found in meteorites.
== Chemical analysis == The total nitrogen content of organic matter is mainly formed by the amino groups in proteins. The total Kjeldahl nitrogen (TKN) is a measure of nitrogen widely used in the analysis of (waste) water, soil, food, feed and organic matter in general. As the name suggests, the Kjeldahl method is applied. More sensitive methods are available.
Sources: en.wikipedia.org
Reversed-phase high-performance liquid chromatography with ultraviolet detection at 214 nanometres is the usual approach. Peak area percentage provides a purity figure relative to other components in the sample. Mass spectrometry is then applied to confirm identity.
Aspartate can cyclise into a succinimide intermediate that later hydrolyses back as isoaspartate. Both forms share the same molecular mass, so mass spectrometry alone cannot tell them apart. This shapes how purity data should be interpreted.
Freeze-dried material is normally kept desiccated below minus twenty degrees Celsius and shielded from light. Solutions are prepared shortly before use and held cold. Repeated thawing is avoided because it accelerates aggregation and degradation.
It is a four-amino-acid peptide with the sequence alanine-glutamate-aspartate-glycine. The chain is unmodified and contains only standard proteinogenic residues, which makes it straightforward to produce by solid-phase synthesis and to characterise by standard peptide methods.