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 2025-10-17. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Amino acid sequence | Ala-Glu-Asp-Gly | Linear tetrapeptide, also written AEDG |
| Molecular mass | About 390.35 g/mol | Value calculated from the sequence |
| Appearance | White to off-white powder | Lyophilised material forms a loose cake |
| Solubility | Freely soluble in water | Also dissolves in isotonic saline |
| Storage | -20 °C, desiccated | Aliquot solutions to avoid freeze–thaw cycling |
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.
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.
Identity and purity are checked by reversed-phase high-performance liquid chromatography, usually with ultraviolet detection near 214 nanometres, where the peptide bond absorbs. Mass spectrometry confirms the expected mass and reveals whether truncation products or adducts are present. Acid hydrolysis followed by amino acid analysis gives the residue ratio, which should approximate one alanine, one glutamate, one aspartate and one glycine. Counter-ions such as acetate or trifluoroacetate remain in the dried product and lower net peptide content, so a stated purity figure on a label does not by itself describe how much peptide a vial holds.
This makes significant differences arise between the small 2p elements, which prefer multiple bonding, and the larger 3p and higher p-elements, which do not. Similar anomalies arise for the 1s, 2p, 3d, 4f, and the hypothetical 5g elements: the degree of this first-row anomaly is highest for the s-block, is moderate for the p-block, and is less pronounced for the d- and f-blocks. In the transition elements, an inner shell is filling, but the size of the atom is still determined by the outer electrons. The increasing nuclear charge across the series and the increased number of inner electrons for shielding somewhat compensate each other, so the decrease in radius is smaller. The 4p and 5d atoms, coming immediately after new types of transition series are first introduced, are smaller than would have been expected, because the added core 3d and 4f subshells provide only incomplete shielding of the nuclear charge for the outer electrons. Hence for example gallium atoms are slightly smaller than aluminium atoms. Together with kainosymmetry, this results in an even-odd difference between the periods (except in the s-block) that is sometimes known as secondary periodicity: elements in even periods have smaller atomic radii and prefer to lose fewer electrons, while elements in odd periods (except the first) differ in the opposite direction. Thus for example many properties in the p-block show a zigzag rather than a smooth trend along the group.
Red blood cells are used to restore oxygen-carrying capacity in people with anaemia due to trauma or other medical problems Whenever a red blood cell transfusion is being considered for a patient, it is good practice to consider not only the haemoglobin level, but also the overall clinical context, patient preferences, and whether there are alternative treatments. If a patient is stable and has a haematinic deficiency, they should be treated for the deficiency (iron deficiency, B12 deficiency, or folate deficiency) rather than being given a red blood cell transfusion. In adults, blood transfusion is typically recommended when hemoglobin levels are below 70 g/L (7 g/dL) in those who have stable vital signs, unless they have anemia due to a haematinic deficiency. Transfusing at a restrictive haemoglobin threshold of between 70 g/L to 80 g/L (7 to 8g/dL) decreased the proportion of people given a red blood cell transfusion by 41% across a broad range of clinical specialties, including those people who are critically ill. There is no evidence that a restrictive transfusion strategy are stronger associated with death or major adverse events (e.g. cardiac events, myocardial infarction, stroke, pneumonia, thromboembolism, infection) compared with a liberal transfusion strategy. There is not enough information in some patient groups to say whether a restrictive or liberal transfusion threshold is better.
== Treatment == The treatment is based on addressing obesity, thus reducing insulin resistance and its undesired effects. Insulin resistance can be treated with metformin and may have a positive impact on reproductive function. Pharmacological treatment by suppression of gonadotropin with estrogen-progesterone oral contraceptives can reduce the hyperandrogenism by decreasing LH (luteinizing hormone) levels. Even their sex hormone binding to globulin increase is also responsible for decreasing body's bio-availability of testosterone. Progestin treatment with desogestrel and norgestimate appears to have fewer androgenic side effects and may be safer to use in persons with abnormal lipid levels or hirsutism. Other proposed treatments include antiandrogenic medications, spironolactone (in combination with oral contraceptives to prevent menstrual cycle irregularities), flutamide, and the 5α-reductase inhibitor finasteride.
== Associated clinical conditions == Hyperaldosteronism is abnormally increased levels of aldosterone, while hypoaldosteronism is abnormally decreased levels of aldosterone. A measurement of aldosterone in blood may be termed a plasma aldosterone concentration (PAC), which may be compared to plasma renin activity (PRA) as an aldosterone-to-renin ratio.
=== Label-free drug screening === Thermofluor has been extensively used in drug screening campaigns. Because Thermofluor detects high affinity binding sites for small molecules on proteins, it can find hits that bind to active site subsites, cofactor sites, or allosteric binding sites with equal efficacy. The method typically requires the use of screening compound concentrations at >10x the desired binding threshold. Setting 5 μM as a reasonable hit threshold consequently requires a test ligand concentration of 50 to 100 μM in the sample well. For most drug compound libraries, where many compounds are not soluble beyond ~100 μM, screening multiple compounds is consequently not feasible owing to solubility issues. Thermofluor screens do not require the development of custom screening reagents (e.g. cleavable substrate analogs), do not require any radioactive reagents, and are generally less sensitive to the effects of compounds that are chemically reactive with protein active site residues, and that consequently show up as undesirable hits in enzyme activity screens.
Sources: en.wikipedia.org
A mass spectrometer resolves the m/z of particles, where m is the accurate mass. As one can glance from the monoisotopic masses, the two molecules are very close in weight. When using a insufficiently powerful mass spectrometer such as a quadrupole mass analyser or a quadrupolar ion trap, the two molecules will show their m/z peaks blended together into one peak. If a high-resolution instrument like an orbitrap or an ion cyclotron resonance is used, these two molecules can be distinguished. The nominal mass is much easier to calculate than the exact monoisotopic mass and serves as an approximation of it. When two particles have the same nominal mass, their monoisotopic masses are usually too close to each other to be resolved using low-resolution instrument. The added precision of monoisotopic mass is very useful when analyzing small organic compounds since compounds with similar weights will not be differentiated if the nominal mass is used. For example, when comparing tyrosine which has a molecular structure of C9H11NO3 with a monoisotopic mass of 182.081 Da and methionine sulphone C5H11NO4S which clearly are 2 different compounds but methionine sulphone has a 182.048 Da.
== Medical uses == Norgestrienone was used in hormonal contraception to prevent pregnancy. It has typically been used as an oral contraceptive at a dosage of 2 mg/day in combination with ethinylestradiol and 350 μ/day when used alone.
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=== Aviation === AEG C.VIII, a World War I German armed reconnaissance aircraft AGO C.VIII, a World War I German reconnaissance aircraft Cierva C.8, a 1926 Spanish experimental autogyro De Havilland Canada C-8 Buffalo, a military transport aircraft of the 1960s Fairchild C-8, a military transport aircraft of the 1930s Fokker C.VIII, a 1928 Dutch reconnaissance aircraft Chicago Express Airlines (defunct) IATA code
Sources: en.wikipedia.org
It is a synthetic tetrapeptide. Its sequence was derived from research on peptide fractions of bovine pineal extract, and the intact AEDG sequence has not been demonstrated as an abundant free peptide in human tissue.
AEDG is the one-letter code for the four amino acids alanine, glutamate, aspartate and glycine in that order. The same molecule is written in three-letter form as Ala-Glu-Asp-Gly.
Identity is normally confirmed by mass spectrometry against the calculated mass of roughly 390.35 g/mol. Purity is then estimated by reversed-phase high-performance liquid chromatography with ultraviolet detection.
The usual approach is reversed-phase HPLC with ultraviolet detection, reported as a percentage of total peak area. Mass spectrometry is used alongside chromatography to confirm identity rather than purity alone.