Everything below concerns counterion. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2025-12-29. Numbers and descriptions here follow the published literature rather than marketing material.
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.
Identity and purity are established with reversed-phase high-performance liquid chromatography and mass spectrometry. The chromatogram shows the main peak and any truncated or oxidised by-products, while the mass spectrum confirms the expected 390 dalton mass. Amino acid analysis can corroborate composition when a sample's origin is uncertain. Counterion content, particularly residual trifluoroacetate from purification, is frequently reported alongside purity because it shifts the net mass of the solid.
Reference material is normally supplied as a lyophilised powder in a sealed vial. Product literature typically recommends storage at minus twenty degrees Celsius or colder, protected from light and moisture. Freeze-thaw cycling is usually avoided because repeated condensation can introduce water into the vial. Working solutions are commonly prepared fresh, aliquoted, and kept cold for short periods rather than stored at ambient temperature. Labelling the date of opening helps track how long a vial has been in use.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C14H22N4O9 | Derived from the four constituent residues |
| Molecular mass | About 390.35 Da | Monoisotopic value, confirmed by mass spectrometry |
| Residue sequence | Ala-Glu-Asp-Gly | Read from the N-terminus to the C-terminus |
| Common synonyms | Epithalon; AEDG | Both forms appear in reference catalogues |
| Net charge near neutral pH | Negative | Two acidic side chains give a low isoelectric point |
The compound is generally presented as a synthetic fragment of epithalamin, a pineal gland extract investigated in the former Soviet Union from the 1970s onward. Vladimir Khavinson and colleagues in Saint Petersburg developed short peptides modelled on such extracts, and epitalon became the most widely cited of those sequences. Most primary reports appeared in Russian-language journals or in proceedings with limited international circulation. Independent replication in laboratories outside that network remains sparse, and much repeated secondary material traces back to a small number of originating groups.
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.
Short peptides such as AEDG are normally supplied as a freeze-dried solid and are kept dry, cold, and shielded from light. Holding at minus twenty degrees Celsius is common for the long term, while a refrigerator suffices for brief periods before use. The material takes up moisture to some degree, so containers should stay sealed and be allowed to reach room temperature before opening, which limits condensation on the contents. Repeated warming and cooling of a single container is discouraged because it admits water and can lower the amount of intact peptide.
Dissolution is usually performed in water or a suitable aqueous buffer, and the resulting liquid is divided into single-use portions before freezing. Freeze-thaw cycling is a recognised source of loss for short peptides, since each cycle can encourage aggregation or adsorption onto container walls. Working solutions are generally kept cold and used within a short window, although published stability data specific to epitalon are thin. Containers should be marked with concentration and date, and solutions examined for cloudiness before use.
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.
Published studies on epitalon are dominated by a small number of research groups, and independent replication in other laboratories remains limited. Proposed mechanisms include activation of telomerase and modulation of melatonin rhythms, but the evidence for either rests mainly on cell cultures and animal models. Whether the peptide produces comparable effects in humans is an open question, and the absence of large controlled trials means the literature is best read as exploratory rather than settled.
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.
During the Qing dynasty, China opened itself to foreign trade under the Canton System through the port of Guangzhou (Canton), with traders from the East India Company visiting the port by the 1690s. Due to the growing British demand for Chinese tea and the Chinese Emperor's lack of interest in British commodities other than silver, British traders resorted to trade in opium as a high-value commodity for which China was not self-sufficient. The English traders had been purchasing small amounts of opium from India for trade since Ralph Fitch first visited in the mid-16th century. Trade in opium was standardized, with production of balls of raw opium, 1.1–1.6 kg (2.4–3.5 lb), 30% water content, wrapped in poppy leaves and petals, and shipped in chests of 60–65 kg (132–143 lb) (one picul). Chests of opium were sold in auctions in Calcutta with the understanding that the independent purchasers would then smuggle it into China. China had a positive balance sheet in trading with the British, which led to a decrease of the British silver stocks. Therefore, the British tried to encourage Chinese opium use to enhance their balance, and they delivered it from Indian provinces under British control. In India, its cultivation, as well as the manufacture and traffic to China, were subject to the British East India Company (BEIC), as a strict monopoly of the British government. There was an extensive and complicated system of BEIC agencies involved in the supervision and management of opium production and distribution in India.
=== Examples === 1 IU of rhEGF is defined as the potency of 0.001 μg of a rhEGF in the "91/530" standard vial. One manufacturer reports that its rhEGF is 1.4 times as potent as the 91/530 standard. 12.5 IU of oxytocin is defined as the potency of 21 μg of pure peptide in the "76/575" standard vial. Before the purification of penicillin was perfected, the amounts were also described in "International Units" (and some non-international arbitrary "units" before them) to account for batch-to-batch variation. See Penicillin § Penicillin units.
Lipolysis, the removal of the fatty acid chains from the glycerol to which they are bound in their storage form as triglycerides (or fats), is carried out by lipases. These lipases are activated by high epinephrine and glucagon levels in the blood (or norepinephrine secreted by sympathetic nerves in adipose tissue), caused by declining blood glucose levels after meals, which simultaneously lowers the insulin level in the blood. Once freed from glycerol, the free fatty acids enter the blood, which transports them, attached to plasma albumin, throughout the body. Long-chain free fatty acids enter metabolizing cells (i.e. most living cells in the body except red blood cells and neurons in the central nervous system) through specific transport proteins, such as the SLC27 family fatty acid transport protein. Red blood cells do not contain mitochondria and are therefore incapable of metabolizing fatty acids; the tissues of the central nervous system cannot use fatty acids, despite containing mitochondria, because long-chain fatty acids (as opposed to medium-chain fatty acids) cannot cross the blood-brain barrier into the interstitial fluids that bathe these cells. Once inside the cell, long-chain-fatty-acid—CoA ligase catalyzes the reaction between a fatty acid molecule with ATP (which is broken down to AMP and inorganic pyrophosphate) to give a fatty acyl-adenylate, which then reacts with free coenzyme A to give a fatty acyl-CoA molecule.
The right-hand side strictly vanishes for a flat geometry only. As a consequence, the integral form of the continuity equation is difficult to define and not necessarily valid for a region within which spacetime is significantly curved (e.g. around a black hole, or across the whole universe).
== Synthesis of GnSAF == GnSAF is produced in the granulosa cells of the small sized antral follicles, which have the highest concentration of GnSAF. Concentrations of GnSAF bioactivity is inversely proportional to follicle size. Upon synthesis, GnSAF is released into peripheral circulation. Follicle-stimulating hormone (FSH) from the anterior pituitary stimulates and prolongs GnSAF biosynthesis in growing small antral follicles in the ovary. FSH induces expression and transcription of exons 12 and 13 of the HSA gene found in granulosa cells. During the early and mid-follicular phase, FSH is secreted to promote growth and proliferation of the granulosa cells, which increases GnSAF concentrations. Once the dominant ovarian follicle has been selected at mid-follicular phase, the non-dominant follicles undergo atresia. Without the presence of small follicles during the late follicular phase, GnSAF concentrations steadily decline to its lowest levels observable in the ovarian cycle. Additionally, the rate of GnSAF biosynthesis by the granulosa cells of the remaining dominant follicle decreases as the follicle approaches maturation. During the transition between luteal phase and follicular phase, GnSAF gradually increases from the late luteal phase and onwards due to the recruitment of follicles and concomitant rise of FSH. The time-course production of GnSAF depends on the serum FSH concentrations. Higher serum concentrations of FSH increases the potency of the attenuating effects of GnSAF on release of LH.
Sources: en.wikipedia.org
=== A public-health approach === A common critical view holds that the war on drugs has been costly and ineffective largely because US federal and state governments have chosen the wrong methods, focusing on interdiction and punishment rather than regulation and treatment of drug abuse and addiction. In the US, current public health-oriented interventions include harm reduction, drug courts, and Law Enforcement Assisted Diversion (LEAD) programs which give police treatment or social services options rather than arrest with minor drug offenses. Harm reduction approaches include provision of sterile syringes, medically supervised injection sites (SIF), and availability of the opioid overdose-countering drug naloxone. As an alternative to imprisonment, drug courts in the US identify substance-abusing offenders and place them under strict court monitoring and community supervision, as well as provide them with long-term treatment services. According to a National Drug Court Institute report, 16.4% of the nation's drug court graduates are rearrested and charged with a felony within one year of completing the program; overall 44.1% of released prisoners end up back in prison within one year. The drug court program is also significantly cheaper than imprisonment. Annual per offender cost is $20,000–$50,000 for imprisonment, and $2,500–$4,000 in the drug court system. A survey by the Substance Abuse and Mental Health Services Administration (SAMHSA) found that substance abusers who remain in treatment longer are less likely to resume their former drug habits.
==== Alpha-particle spectroscopy ==== Alpha-particle spectroscopy is a method of measuring the radionuclides based on emission of α particles. They can be measured by a variety of detectors, including liquid scintillation counters, gas ionization detectors, and ion-implanted silicon semiconductor detectors. Typical alpha-particle spectrometers have low backgrounds and measure particles ranging from 3 to 10 MeV. Radionuclides that decay through α emission tend to eject α particles with discrete, characteristic energies between 4 and 6 MeV. These energies become attenuated as they pass through the layers of sample. Increasing the distance between the source and the detector can lead to improved resolution, but decreased particle detection. The advantages of alpha-particle spectroscopy include relatively inexpensive equipment costs, low backgrounds, high selectivity, and good throughput capabilities with the use of multi-chamber systems. There are also disadvantages of alpha-particle spectroscopy. One disadvantage is that there must be significant sample preparation to obtain useful spectroscopy sources. Also, spectral interferences or artifacts from extensive preparation prior to counting, to minimize this high purity acids are needed. Another disadvantage is that measurements require a large quantity of material which can also lead to poor resolution. Also, undesired spectral overlap and long analysis times are disadvantages.
== See also == Substituted methoxyphenethylamine Scaline § Related compounds Dimethoxyphenethylamine 3-Methoxytyramine Mescaline 3-Methoxy-4-ethoxyphenethylamine (MEPEA; 3-desmethoxyescaline) 3-Methoxy-4-allyloxyphenethylamine (MAPEA; 3-desmethoxyallylescaline) Pachycereus pringlei § Constituents and effects
No nihonium atoms were observed after chemical separation, implying an unexpectedly large retention of nihonium atoms on PTFE surfaces. This experimental result for the interaction limit of nihonium atoms with a PTFE surface (−ΔHPTFEads(Nh) > 45 kJ/mol) disagrees significantly with previous theory, which expected a lower value of 14.00 kJ/mol. This suggests that the nihonium species involved in the previous experiment was likely not elemental nihonium but rather nihonium hydroxide, and that high-temperature techniques such as vacuum chromatography would be necessary to further probe the behaviour of elemental nihonium. Bromine saturated with boron tribromide has been suggested as a carrier gas for experiments on nihonium chemistry; this oxidises nihonium's lighter congener thallium to thallium(III), providing an avenue to investigate the oxidation states of nihonium, similar to earlier experiments done on the bromides of group 5 elements, including the superheavy dubnium. A 2024 experiment at the GSI, producing 284Nh via the 243Am+48Ca reaction as daughter of 288Mc, studied the adsorption of nihonium and moscovium on SiO2 and gold surfaces. The adsorption enthalpy of nihonium on SiO2 was determined experimentally as −ΔHSiO2ads(Nh) = 58+8−3 kJ/mol (68% confidence interval). Nihonium was determined to be less reactive with the SiO2 surface than its lighter congener thallium, but more reactive than its closed-shell neighbours copernicium and flerovium. This arises because of the relativistic stabilisation of the 7p1/2 shell.
Sources: en.wikipedia.org
It is a four-amino-acid peptide built from alanine, glutamate, aspartate and glycine in that order. Its formula is C14H22N4O9, and it is made by chemical synthesis rather than extracted from tissue. The synthetic peptide is a single defined molecule, unlike the pineal extracts it is often compared with.
No. The two spellings refer to the same tetrapeptide, and the difference reflects transliteration from Russian. Laboratories and catalogues use both forms interchangeably. The material is also indexed as AEDG, taken from the one-letter codes of its residues.
Epithalamin is a mixed preparation derived from animal pineal tissue and contains many peptides. Epitalon is one synthetic sequence chosen for study from that broader mixture. Statements about one do not transfer directly to the other.
Sealed lyophilised powder is normally kept at minus twenty degrees Celsius or below, away from light and moisture. Vials are allowed to reach room temperature before opening to limit condensation. Repeated warming and cooling of the same vial is discouraged.