This is a working overview of AEDG, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-07-10 and is reviewed periodically as new material appears.
（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.
Chemically, the molecule consists of four amino acid residues joined by three peptide bonds, with a free N-terminal amino group and a free C-terminal carboxyl group. Its molecular formula is C14H22N4O9, and its monoisotopic mass is approximately 390 daltons. The acidic glutamate and aspartate side chains give the peptide a net negative charge near neutral pH, a property that shapes its chromatographic behaviour and solubility profile. No disulfide bridges or other post-translational modifications are present, so the primary sequence alone defines the structure.
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.
Epitalon is a synthetic four-amino-acid peptide with the sequence alanine-glutamate-aspartate-glycine, commonly abbreviated AEDG. Its molecular formula is C14H22N4O9, and its calculated molar mass is approximately 390.35 grams per mole. The compound is a short fragment related to a peptide fraction isolated from bovine pineal gland extracts, and it is normally supplied as a lyophilised powder intended for laboratory research. It is not a registered pharmaceutical product in most countries.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Linear tetrapeptide | Four residues joined by three peptide bonds |
| Sequence | Ala-Glu-Asp-Gly | Commonly abbreviated AEDG |
| Molecular formula | C14H22N4O9 | Free acid form |
| Monoisotopic mass | Approximately 390 Da | Matches values reported from mass spectrometry |
| Net charge near neutral pH | Negative | Contributed by glutamate and aspartate side chains |
Epitalon is a synthetic tetrapeptide with the amino acid sequence alanine-glutamate-aspartate-glycine, abbreviated Ala-Glu-Asp-Gly or AEDG. It was developed by the Russian researcher Vladimir Khavinson and colleagues during work on peptide bioregulators derived from the pineal gland. The compound is short enough to be produced by standard solid-phase peptide synthesis and is typically handled as a lyophilized white powder. Its small size distinguishes it from larger pineal peptides such as epithalamin, a complex extract from which the tetrapeptide was conceptually derived.
The four residues give epitalon a molecular formula of C14H22N4O9 and a molecular weight near 390.35 daltons. The presence of two acidic residues, glutamate and aspartate, makes the free peptide strongly acidic, while the alanine and glycine ends provide neutral, nonpolar character. This combination produces a molecule with substantial water solubility. Because there are no cysteine, methionine, or tryptophan residues, the peptide lacks the most common oxidation-sensitive side chains, which simplifies handling compared with many longer peptides.
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.
=== Side effects === Sulfonylureas – as opposed to metformin, the thiazolidinediones, pramlintide and other newer treatments – may induce hypoglycemia as a result of excesses in insulin production and release. Hypoglycemia appears to happen more often with sulfonylureas than compared to other treatments. This typically occurs if the dose is too high, and the patient is fasting. Some people attempt to change eating habits to prevent this, however it can be counterproductive. Like insulin, sulfonylureas can induce weight gain, mainly as a result of their effect to increase insulin levels and thus use of glucose and other metabolic fuels. Other side-effects are: gastrointestinal upset, headache and hypersensitivity reactions. Skin reactions and dark-colored urine, which indicates a liver injury, are other side effects that have been observed. The safety of sulfonylurea therapy in pregnancy is unestablished. Prolonged hypoglycemia (4 to 10 days) has been reported in children borne to mothers taking sulfonylureas at the time of delivery. Impairment of liver or kidney function increase the risk of hypoglycemia, and are contraindications. Since other antidiabetic drugs cannot be used either under these circumstances, insulin therapy is typically recommended during pregnancy and in liver and kidney failure, although some of the newer agents offer potentially better options. A 2011 Cochrane review found evidence that treatment of LADA using sulfonylureas lead to earlier insulin dependence in approximately 30% of cases.
== Activity and stability == Pepsin is most active in acidic environments between pH 1.5 to 2.5. Accordingly, its primary site of synthesis and activity is in the stomach (pH 1.5 to 2). In humans the concentration of pepsin in the stomach reaches 0.5 – 1 mg/mL. Pepsin is inactive at pH 6.5 and above; however, pepsin is not fully denatured or irreversibly inactivated until pH 8.0. Therefore, pepsin in solutions of up to pH 8.0 can be reactivated upon re-acidification. The stability of pepsin at high pH has significant implications on disease attributed to laryngopharyngeal reflux. Pepsin remains in the larynx following a gastric reflux event. At the mean pH of the laryngopharynx (pH = 6.8) pepsin would be inactive but could be reactivated upon subsequent acid reflux events resulting in damage to local tissues. Pepsin exhibits a broad cleavage specificity. Pepsin will digest up to 20% of ingested amide bonds. Residues in the P1 and P1' positions are most important in determining cleavage probability. Generally, hydrophobic amino acids at P1 and P1' positions increase cleavage probability. Phenylalanine, leucine and methionine at the P1 position, and phenylalanine, tryptophan and tyrosine at the P1' position result in the highest cleavage probability. Cleavage is disfavoured by positively charged amino acids histidine, lysine and arginine at the P1 position.
=== Modern usage === As part of standard TB chemotherapy, isoniazid is now typically administered alongside at least three other drugs—ethambutol, pyrazinamide, and rifampin—for six to nine months. Isoniazid is also included on the World Health Organization's List of Essential Medicines. The World Health Organization classifies isoniazid as critically important for human medicine.
Sources: en.wikipedia.org
== History == In the mid-1980s, McDonald's sought to introduce menu items positioned as fresher or lighter options to compete with the Whopper from rival chain Burger King. Reporting on the chain's expansion into fresh vegetables noted that McDonald's had historically resisted placing lettuce and tomato on burgers, fearing the hot meat would wilt the ingredients and make the bun soggy. McDonald's developed a dual-compartment sandwich package that physically separated the hot and cold components. The burger was invented by Wil May, a Lufkin, Texas franchisee. It rolled out nationwide in 1985 as the McDLT. McDonald's use of polystyrene foam packaging became a frequent target of environmental criticism during the late 1980s. Activists often cited the McDLT's large container as a symbol of excessive waste. In late 1990, amid growing public and regulatory pressure, McDonald's announced it would phase out foam packaging. The chain discontinued the McDLT in January 1991, replacing it with the McLean Deluxe, a lower-fat burger that did not use the dual-compartment packaging. McDonald's revisited the "hot and cold" concept in later years with the Big N' Tasty, though it was served in standard cardboard and paper packaging. In 2025, Al Roker said he wished McDonald's would bring back the McDLT.
Indigenous Americans in northern Peru also used bottle gourds as floats for fishing nets. Bulletproof vest – Ichcahuipilli, was a military armor used by various Mesoamerican cultures. It consisted of a layered cotton shirt, at least 2 inches thick, hardened with brine and other substances. It was originally intended to protect the wearer against projectiles and other weaponry, such as spears, arrows, and obsidian swords, but later was discovered to be capable of stopping musket shots. Bunk bed – the Iroquoian longhouses housed several families together. The concept of bunk beds was developed by these Native American peoples, since these longhouses included several bed combinations which featured one bed built on top of another, akin to bunk beds in modern times.
==== MeSH D13.570.800 – ribonucleosides ==== MeSH D13.570.800.096 – adenosine MeSH D13.570.800.096.250 – adenosine-5'-(n-ethylcarboxamide) MeSH D13.570.800.096.262 – s-adenosylhomocysteine MeSH D13.570.800.096.264 – s-adenosylmethionine MeSH D13.570.800.096.300 – 2-chloroadenosine MeSH D13.570.800.096.300.200 – cladribine MeSH D13.570.800.096.500 – isopentenyladenosine MeSH D13.570.800.096.630 – phenylisopropyladenosine MeSH D13.570.800.286 – cytidine MeSH D13.570.800.286.300 – azacitidine MeSH D13.570.800.330 – dichlororibofuranosylbenzimidazole MeSH D13.570.800.410 – formycins MeSH D13.570.800.410.200 – coformycin MeSH D13.570.800.453 – guanosine MeSH D13.570.800.453.500 – nucleoside q MeSH D13.570.800.573 – inosine MeSH D13.570.800.573.130 – didanosine MeSH D13.570.800.573.450 – inosine pranobex MeSH D13.570.800.573.900 – thioinosine MeSH D13.570.800.573.900.500 – methylthioinosine MeSH D13.570.800.790 – ribavirin MeSH D13.570.800.810 – showdomycin MeSH D13.570.800.840 – toyocamycin MeSH D13.570.800.850 – tubercidin MeSH D13.570.800.892 – uridine MeSH D13.570.800.892.176 – azauridine MeSH D13.570.800.892.250 – 3-deazauridine MeSH D13.570.800.892.628 – pseudouridine MeSH D13.570.800.892.800 – tetrahydrouridine MeSH D13.570.800.892.829 – thiouridine
Sources: en.wikipedia.org
It is a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, often abbreviated AEDG. The molecule is linear and contains no modified residues, so it is fully described by its sequence.
The compound came out of work on epithalamin, a peptide preparation derived from pineal tissue, conducted largely in Russian laboratories. Later studies in other countries examined it mainly in cell cultures and animal models.
The tetrapeptide sequence is a synthetic construct rather than a described circulating peptide. It was derived by analogy to peptide fractions obtained from tissue extracts, not isolated from blood or tissue as such.
It is a synthetic tetrapeptide built from alanine, glutamate, aspartate and glycine. The four residues are joined by standard peptide bonds, giving a linear chain rather than a branched structure.