This is a working overview of Mass spectrometry, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2025-09-28. Anything still debated is marked as such rather than presented as settled.
In its supplied form epitalon is a white to off-white powder, usually lyophilized and often hygroscopic. It dissolves readily in water and in aqueous buffers, and it is commonly handled as the acetate or trifluoroacetate salt to improve stability during purification and drying. The amide backbone is labile in aqueous media, so solutions are less durable than the dry solid. Handling notes in the chemical literature therefore emphasize keeping the powder dry, cool and shielded from light until it is dissolved.
Epitalon is a synthetic tetrapeptide whose sequence is alanine-glutamate-aspartate-glycine, written in single-letter code as AEDG. The four residues are joined by three peptide bonds, giving a linear backbone with no branching and no disulfide bridges. Its calculated molecular mass for the free form is approximately 390.3 daltons, a figure that rises when the compound is supplied as an acetate or trifluoroacetate salt. Because the chain is short, the molecule is defined entirely by its residue order rather than by any folded three-dimensional structure.
The compound is described in the literature as a derivative of epithalamin, a preparation obtained from bovine pineal tissue. Work on this peptide family was carried out mainly by a research group in Saint Petersburg beginning in the 1980s, and the substance was later registered for clinical use in Russia under the name Epitalon. Outside that region it is generally treated as a research chemical rather than an approved medicine. Statements about its biological activity rest on a relatively small number of studies, and independent replication remains limited.
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.
Stability of the tetrapeptide follows ordinary peptide chemistry rather than any unusual structural feature. The aspartate-glycine pair is prone to aspartimide formation under mildly basic or neutral conditions, and deamidation can follow, altering both mass and chromatographic retention. Dry lyophilised powder kept at or below minus twenty degrees Celsius is the usual handling recommendation, with repeated freeze-thaw cycles avoided. Once dissolved in neutral aqueous buffer, degradation proceeds over days to weeks depending on pH and temperature, while acidic conditions generally slow the aspartimide route. A formal stability-indicating study has not been published in the indexed literature.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic tetrapeptide | Four residues, linear chain |
| Residue sequence | Ala-Glu-Asp-Gly | Single-letter form AEDG |
| Calculated mass | 390.3 daltons | Value for the free, uncharged form |
| Appearance | White to off-white powder | Usually supplied lyophilized |
| Solubility | Freely soluble in water | Often handled as a salt form |
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.
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.
Regulatory treatment differs by country. No formulation of epitalon holds a marketing authorisation as a medicine in the United States or the European Union, where material sold for laboratory use is handled as a research chemical and is not intended for human consumption. In Russia, several short peptide preparations from the same institute's peptide series are registered medicinal products, and epitalon appears in that national context. Elsewhere it is frequently offered as a cosmetic ingredient, a category with lighter requirements. Advertising claims about longevity or disease prevention are restricted in most jurisdictions, which limits how sellers describe the compound.
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.
The peptide is a synthetic analogue of epithalamin, a preparation extracted from bovine pineal glands. Investigators sought a short, chemically defined molecule that would reproduce some of the endocrine and gerontological observations attributed to the glandular extract. Proposed mechanisms centre on induction of telomerase activity, an effect reported in cultured human somatic cells in the early 2000s, together with influences on melatonin secretion and neuroendocrine regulation. Those mechanisms remain incompletely characterised, and the reported telomerase response has not been consistently reproduced by independent groups working in comparable systems.
Published work on this compound consists mainly of in vitro experiments, animal studies, and small clinical investigations, a substantial share of which appeared in Russian-language journals. Sample sizes are generally small, control conditions differ between studies, and several endpoints rely on markers whose clinical meaning is itself debated. Reviews of the longevity field treat the peptide as an early example of telomerase-directed research rather than an established intervention. Regulatory treatment varies by country: some jurisdictions place it under prescription controls, others treat it as a laboratory material, and importation may be restricted regardless of local status.
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.
In September 2022, NewsGuard Technologies reported that among the TikTok searches it had conducted and analyzed from the US, 19.4% surfaced misinformation such as questionable or harmful content about COVID-19 vaccines, homemade remedies, the 2020 US elections, the Russian invasion of Ukraine, the Robb Elementary School shooting, and abortion. NewsGuard suggested that in contrast, results from Google were of higher quality. Mashable's own test from Australia found innocuous results after searching for "getting my COVID vaccine" but suggestions such as "climate change is a myth" after typing in "climate change". In November 2023, Singaporean Law and Home Affairs Minister K. Shanmugam applied for court orders requiring TikTok to provide information on the identity of three users that he accuses of spreading false and defamatory information about him. The users had shared on TikTok an article published by celebscritic.com alleging that K. Shanmugam was involved in an extra-marital affair. According to an investigation published in September 2025 by Moldovan newspaper Ziarul de Gardă, before the 2025 Moldovan parliamentary election, hundreds of accounts with false identities were created to spread Russian propaganda in TikTok and Facebook. That month, Bloomberg reported, citing European officials and documents of undisclosed origin, that Russia had prepared a plan to interfere in the election, which would have included a disinformation campaign in both Romanian and Russian on Facebook, Telegram and TikTok.
The resulting roGFP variants, named roGFP1-R1 through roGFP1-R14, are much more suitable for live-cell imaging. The roGFP1-R12 variant has been used to monitor redox potential in bacteria and yeast, but also for studies of spatially-organized redox potential in live, multicellular organisms such as the model nematode C. elegans. In addition, roGFPs are used to investigate the topology of ER proteins, or to analyze the ROS production capacity of chemicals.
Béjar stated that his expressions on the Navy were about a bomb plot against the Minister of War in 1975, and an attack against two Cuban fishing boats off the coast of Peru in 1977. Declassified documents show that the US Embassy suspected that these attacks were carried out by right-wing sectors of the Navy, which were unhappy with the military junta's close ties to Cuba at the time.
Alamethicin is a channel-forming peptide antibiotic, produced by the fungus Trichoderma viride. It belongs to peptaibol peptides which contain the non-proteinogenic amino acid residue Aib (2-aminoisobutyric acid). This residue strongly induces formation of alpha-helical structure. The peptide sequence is
==== Gastrointenstinal tract ==== Age-related changes in OPRK1 gene expression were observed in mouse gastrointestinal tract, with mRNA expression significantly decreased in the distal ileum in 12-month-old mice compared to 6-month-old animals, though no statistically significant differences were detected in the stomach and colon. Protein expression of dynorphin in the colon was lower in older mice.
Sources: en.wikipedia.org
== Legality == In the United States, a letter from Terrence L. Boos, Ph.D., Chief Drug & Chemical Evaluation Section Diversion Control Division at the DEA shows they consider nor-BNI a Schedule II substance as a derivative of noroxymorphone due to its broad definition in the CSA covering "derivatives". However, no court cases are known to exist for its prosecution and it is possible this could be challenged in court.
With use, muscles consume energy derived from both fat and glycogen. Due to the large size of leg muscles, walking, running and cycling are the most effective means of exercise to reduce body fat. Exercise affects macronutrient balance. During moderate exercise, equivalent to a brisk walk, there is a shift to greater use of fat as a fuel. To maintain health, the American Heart Association recommends a minimum of 30 minutes of moderate exercise at least 5 days a week. The Cochrane Collaboration found that exercising alone led to limited weight loss. In combination with diet, however, it resulted in a 1 kilogram weight loss over dieting alone. A 1.5 kilograms (3.3 pounds) loss was observed with a greater degree of exercise. Even though exercise as carried out in the general population has only modest effects, a dose response curve is found and very intense exercise can lead to substantial weight loss. During 20 weeks of basic military training with no dietary restriction, obese military recruits lost 12.5 kg (28 lb). High levels of physical activity seem to be necessary to maintain weight loss. A pedometer appears useful for motivation. Over an average of 18-weeks of use, physical activity increased by 27% resulting in a 0.38 decrease in BMI. Signs that encourage the use of stairs as well as community campaigns have been shown to be effective in increasing exercise in a population. The city of Bogotá, Colombia, for example, blocks off 113 kilometers (70 mi) of roads every Sunday and on holidays to make it easier for its citizens to get exercise.
berberine and oxyberberine caffeic acid ethyl ester isovanillin ferulic acid (+/-)-5,5'-dimethoxylariciresinol methyl beta-orsellinate obacunone limonin and 12alpha-hydroxylimonin nomilin γ-Fagarine canthin-6-one 4-methoxy-N-methyl-2-quinolone palmatine and oxypalmatine (+/-)-lyoniresinol β-sitosterol stigmasterine amurenlactone A amurenamide A phellodensins and phellodenols (2R)-sodium 3-phenyllactate jatrorrhizine an isocoumarin, 3-acetyl-3,4-dihydro-5,6-dimethoxy-1H-2-benzopyran-1-one Ala-Pro-Trp-Cys, a glutathione S-transferase activating peptide
Cardiovascular: dyslipidemia (e.g., increased LDLTooltip low-density lipoprotein levels, decreased HDLTooltip high-density lipoprotein levels, reduced apo-A1Tooltip apolipoprotein A1 levels), atherosclerosis, elevated hematocrit, hypertension, left ventricular hypertrophy, cardiomyopathy, myocardial hypertrophy, polycythemia/erythrocytosis, arrhythmias, thrombosis (e.g., embolism, stroke), myocardial infarction, sudden death. Hepatic: elevated liver function tests (ASTTooltip aspartate aminotransferase, ALTTooltip alanine aminotransferase, bilirubin, LDHTooltip lactic dehydrogenase, ALPTooltip alkaline phosphatase), hepatotoxicity, jaundice, hepatic steatosis, hepatocellular adenoma, hepatocellular carcinoma, cholestasis, peliosis hepatis; all mostly or exclusively with 17α-alkylated AAS. Renal: renal hypertrophy, nephropathy, acute renal failure (secondary to rhabdomyolysis), focal segmental glomerulosclerosis, renal cell carcinoma. Others: glucose intolerance, insulin resistance, immune dysfunction.
Sources: en.wikipedia.org
The peptide contains four residues in the order alanine, glutamate, aspartate and glycine, abbreviated AEDG. The chain is linear and held together by three peptide bonds. Its calculated mass for the uncharged free form is about 390.3 daltons.
Epithalamin refers to a crude preparation derived from bovine pineal tissue, which contains many components. Epitalon is a single synthetic tetrapeptide identified from that material and produced by chemical synthesis. The two names are sometimes confused because early reports treated the synthetic peptide as an active fragment of the extract.
It has been registered for clinical use in Russia, where it is associated with a small family of short peptides. In most other jurisdictions it is not an approved medicine and is traded as a research chemical. Regulatory status varies by country and changes over time.
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.