Everything below concerns certificate of analysis. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2025-09-10. Numbers and descriptions here follow the published literature rather than marketing material.
Published work on this peptide almost always uses intranasal delivery, with drops or a spray applied to the nasal mucosa. Some animal experiments have used subcutaneous or intraperitoneal injection, and a smaller number have compared routes directly. Oral administration is not a focus of the literature, because short peptides of this size are broken down by digestive enzymes and cross intestinal barriers poorly. How much of an intranasal dose reaches the bloodstream intact in humans remains an open question.
Animal studies have examined behaviour in tests of anxiety, memory retention and stress response, and several report changes in neurotrophic or neurotransmitter-related markers. The human evidence base is much smaller, consisting mainly of short trials conducted in Russia with limited reporting in English-language journals. Sample sizes are modest and outcome measures vary between studies, so the findings are best described as preliminary. Independent replication under modern trial standards has not been widely reported.
Peptide stability depends strongly on temperature, moisture, and pH. Lyophilized Selank is generally most stable when stored cold and dry, with freezer temperatures commonly used for long-term storage. In solution, the compound is susceptible to hydrolysis and to microbial growth if it is not handled aseptically. The C-terminal proline-rich extension appears to slow enzymatic cleavage relative to tuftsin, though quantitative degradation rates vary with the matrix and the conditions tested. Published stability data specific to Selank remain sparse.
Quality assessment of Selank samples typically combines purity determination with identity confirmation and counter-ion analysis. Purity is usually reported as a percentage by chromatographic area, with values above 95 percent often quoted for research-grade material. Water content and residual solvents are checked in lyophilized batches because they affect both stability and accurate mass determination. A reported purity figure does not by itself establish that a sample is the intended sequence, so orthogonal methods are needed to rule out sequence isomers or truncation products.
Characterization of Selank in laboratory settings relies on standard peptide analytical techniques. Reverse-phase high-performance liquid chromatography separates the peptide from related impurities and degradation products, while mass spectrometry confirms molecular identity through accurate mass measurement. Amino acid analysis and peptide sequencing verify the primary structure when reference material is unavailable. Because Selank is a short chain, fragmentation-based analysis produces a diagnostic ion pattern that supports confident identification.
| Property | Value | Notes |
|---|---|---|
| Common route | Intranasal | Also injected in some animal work |
| Solubility class | Freely soluble in water | Solid form is hygroscopic |
| Typical storage | About -20 degrees Celsius | Keep desiccated and dark |
| Purity method | Reverse-phase HPLC | Reported as area percent |
| Confirmatory method | Mass spectrometry | Verifies expected molecular mass |
Peptide bonds are vulnerable to protease attack, and Selank is no exception. Measured half-life in serum is short, on the order of minutes in several reports, which explains why intranasal administration is the common route described in the literature. Absorption across the nasal mucosa partially bypasses first-pass hepatic metabolism. Quantitative data on human bioavailability remain limited and are difficult to compare across studies.
Lyophilised material kept dry at minus 20 degrees Celsius or colder is the most stable form, and suppliers commonly state a shelf life of two years or more under those conditions. Once dissolved, degradation accelerates through hydrolysis and deamidation, particularly at alkaline pH or elevated temperature. Working solutions are usually divided into single-use aliquots to avoid repeated freeze-thaw cycles. The choice of reconstitution solvent affects both stability and the ionic strength of the final preparation.
Reverse-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres is the standard purity method. Mass spectrometry, typically electrospray ionisation, confirms identity through the expected mass-to-charge pattern. Amino acid analysis can verify composition independently. Chiral purity requires separate techniques such as derivatisation followed by chromatographic separation, and such data are rarely reported for research-grade material.
Lyophilized material is generally stable for extended periods when kept dry at or below minus twenty degrees Celsius. Working solutions are less stable, and common practice is to aliquot and freeze them so that repeated freeze-thaw cycles are avoided. Aqueous solutions are sensitive to pH extremes and to microbial growth, so short-term storage at refrigerator temperature is typical. Oxidation and hydrolysis are the principal degradation routes. Reconstitution with sterile water or a mild buffer is standard, and solutions should be protected from light.
Regulatory treatment varies by jurisdiction. In Russia the compound is a registered prescription product, while in the European Union and the United States it is generally handled as a research chemical without a marketing authorization. Suppliers therefore operate outside pharmaceutical oversight, and buyers rely on supplier documentation for purity and identity claims. Chain of custody and third-party testing are the main verification tools. Analysts note that the absence of a pharmacopoeial monograph for research-grade material limits standardization across vendors.
Enzymatic stability motivates the extra three residues at the carboxyl end. Native tuftsin is cleaved quickly by circulating aminopeptidases and carboxypeptidases, which limits its duration of action and its usefulness as a tool compound. Extending the chain with proline-rich segments is a common design tactic because proline constrains the backbone and slows proteolysis. The same Pro-Gly-Pro motif appears in other Russian-developed peptides of the era. Whether the full seven-residue chain is required for activity, or whether it acts mainly as a prodrug releasing tuftsin, remains unresolved.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. Its four N-terminal residues reproduce tuftsin, a tetrapeptide fragment of the immunoglobulin heavy chain, while the C-terminal Pro-Gly-Pro extension is a synthetic addition. The peptide has a molecular mass near 752 daltons and carries a net positive charge at physiological pH because of the arginine and lysine side chains. Published indexes list it under the name Selank and the sequence abbreviation TKPRPGP. Solid-phase peptide synthesis is the standard production route for research quantities.
Peptide bonds in selank are susceptible to hydrolysis under strongly acidic or basic conditions, and the terminal proline residues are vulnerable to exopeptidase activity in biological samples. Lyophilized powder stored dry at -20 °C typically remains stable for extended periods, whereas aqueous solutions degrade faster and may lose measurable purity within days to weeks depending on pH, temperature, and microbial load. Repeated freeze-thaw cycles promote aggregation and adsorption to container surfaces. For analytical work, solutions are usually prepared fresh, kept cold, and used within a single working day.
Handling follows standard practice for research peptides. Material is weighed in a low-humidity environment because the powder absorbs atmospheric moisture. Purity is reported as the percentage area of the main peak in a chromatogram, with specifications commonly set at 95 percent or higher; values below that threshold indicate the presence of truncated or modified species. Residual trifluoroacetate from purification is often present and may affect mass balance. Certificates of analysis should state the analytical method, the column and gradient used, and the lot-specific retention time so that results can be compared across suppliers.
=== Sales === The Valve Index headset, controllers, and base stations sold out in the US, Canada, and Europe within a week of the Alyx announcement. By mid-January 2020, they were sold out in all 31 regions. According to Superdata, Valve sold 103,000 Index units in the fourth quarter of 2019 as a result of the Alyx announcements, compared to the total 149,000 sold throughout 2019, and the Index was the highest-selling VR headset for PCs during that quarter. Though Valve had expected to supply several Index orders in time for the release of Alyx, the COVID-19 pandemic limited their supply chain. Valve's Greg Coomer said Valve knew many people would not play Alyx on launch and that its audience was "relatively small right now". Newell described it as a "forward investment" into long-term technologies. In 2021, PCGamesN wrote that though it was "artfully crafted", Alyx had had little cultural impact. As of December 2024, Alyx had sold more than two million copies.
Social defeat Likewise, the hypothalamus has a role in social defeat: nuclei in medial zone are also mobilized during an encounter with an aggressive conspecific. The defeated animal has an increase in Fos levels in sexually dimorphic structures, such as the medial pre-optic nucleus, the ventrolateral part of ventromedial nucleus, and the ventral premammilary nucleus. Such structures are important in other social behaviors, such as sexual and aggressive behaviors. Moreover, the premammillary nucleus also is mobilized, the dorsomedial part but not the ventrolateral part. Lesions in this nucleus abolish passive defensive behavior, like freezing and the "on-the-back" posture.
CPGS – Council of Protestants in Guiding and Scouting DESMOS – International Link of Orthodox Christian Scouts ICCS – International Catholic Conference of Scouting IFJS – International Forum of Jewish Scouts IUMS – International Union of Muslim Scouts WBSB – World Buddhist Scout Brotherhood Won-Buddhist Scout Council The Church of the Latter Day Saints
A biosynthesis alternative utilizes genetically engineered yeast species Saccharomyces cerevisiae to synthesize retinal and retinol, using xylose as a starting substrate. This was accomplished by having the yeast first synthesize β-carotene and then the cleaving enzyme β-carotene 15,15'-dioxygenase to yield retinal.
Sources: en.wikipedia.org
Medical schools began to be set up in the United States towards the end of the 18th century. Classes in anatomy needed a continual stream of cadavers for dissection, and these were difficult to obtain. Philadelphia, Baltimore, and New York were all renowned for body snatching activity as criminals raided graveyards at night, removing newly buried corpses from their coffins. A similar problem existed in Britain where demand for bodies became so great that grave-raiding and even anatomy murder were practised to obtain cadavers. Some graveyards were, in consequence, protected with watchtowers. The practice was halted in Britain by the Anatomy Act of 1832, while in the United States, similar legislation was enacted after the physician William S. Forbes of Jefferson Medical College was found guilty in 1882 of "complicity with resurrectionists in the despoliation of graves in Lebanon Cemetery".The teaching of anatomy in Britain was transformed by Sir John Struthers, Regius Professor of Anatomy at the University of Aberdeen from 1863 to 1889. He was responsible for setting up the system of three years of "pre-clinical" academic teaching in the sciences underlying medicine, including especially anatomy. This system lasted until the reform of medical training in 1993 and 2003. As well as teaching, he collected many vertebrate skeletons for his museum of comparative anatomy, published over 70 research papers, and became famous for his public dissection of the Tay Whale. From 1822 the Royal College of Surgeons regulated the teaching of anatomy in medical schools.
Analogues of MDMA include amphetamine, methamphetamine, homopiperonylamine (MDPEA), homarylamine (MDMPEA), lophophine (MMDPEA), MDA, MMDA, MMDA-2, DMMDA, DMMDA-2, MDEA, MDOH, MDMOH (FLEA), N-t-BOC-MDMA, methylone (MDMC), MBDB, 5-MAPB, 6-MAPB, 5-MAPBT, 6-MAPBT, SDMA, ODMA, SeDMA, TDMA, MDAI, and MDAT, among many others. Deuterated analogues of MDMA such as d2-MDMA have been described as well.
=== Degradation === Under extreme alkaline conditions, bronopol decomposes in aqueous solution and very low levels of formaldehyde are produced. Liberated formaldehyde is not responsible for the biological activity associated with bronopol. Other decomposition products detected after bronopol breakdown are bromide ion, nitrite ion, bromonitroethanol and 2-hydroxymethyl-2-nitropropane-1,3-diol.
== Panel tests == A physician may order many laboratory tests on one specimen, referred to as a test panel, when a single test cannot provide sufficient information to make a swift and accurate diagnosis and treatment plan. A test panel is a group of many tests a clinical chemists do on one sample to look for changes in many analytes that may be indicative of specific medical concerns or the health status of an organ system. Thus, panel tests provide a more extensive evaluation of a patient's health, have higher predictive values for confirming or disproving a disease, and are quick and cost-effective.
== Research history == GLP-1 was first described 1979 by a research group of Werner Creutzfeldt in Göttingen. Also Jens Juul Holst worked in this area. In the early 1980s, Richard Goodman and P. Kay Lund were postdoctoral researchers working in Joel Habener's laboratory at Massachusetts General Hospital. Starting in 1979, Goodman harvested DNA from American anglerfish islet cells and spliced the DNA into bacteria to find the gene for somatostatin; Lund then joined the Habener laboratory and used Goodman's bacteria to identify the gene for glucagon. In 1982, they published their discovery that the gene for proglucagon actually codes for three peptides, namely glucagon and two novel peptides. Those two novel peptides were later isolated, identified, and investigated by other researchers, and are now known as glucagon-like peptide-1 and glucagon-like peptide-2. In the 1980s, Svetlana Mojsov worked on the identification of GLP-1 at Massachusetts General Hospital, where she was head of a peptide synthesis facility. To try to identify whether a specific fragment of GLP-q was an incretin, Mojsov created an incretin-antibody and developed ways to track its presence. She identified that a stretch of 31 amino acids in the GLP-1 was an incretin. Mojsov and her collaborators Daniel J. Drucker and Habener showed that small quantities of laboratory-synthesized GLP-1 could trigger insulin. Mojsov fought to have her name included in patents, with Mass General eventually agreeing to amend four patents to include her name. She received her one-third of drug royalties for one year.
Sources: en.wikipedia.org
=== Composition === Fresh kava root contains on average 80% water. Dried root contains approximately 43% starch, 20% dietary fiber, 15% kavalactones, 12% water, 3.2% sugars, 3.6% protein, and 3.2% minerals. In general, kavalactone content is greatest in the roots and decreases higher up the plant into the stems and leaves. Relative concentrations of 15%, 10%, and 5% have been observed in the root, stump, and basal stems, respectively. The relative content of kavalactones depends not only on plant segment but also on the kava plant variety, plant maturity, geographic location, and time of harvest. The kavalactones present are kavain, desmethoxyyangonin, and yangonin, which are higher in the roots than in the stems and leaves, with dihydrokavain, methysticin, and dihydromethysticin also present. The mature roots of the kava plant are harvested after a minimum of four years (at least five years, ideally) for peak kavalactone content. Most kava plants produce around 50 kg (110 lb) of root when they are harvested. Kava root is classified into two categories: crown root (or chips) and lateral root. Crown roots are the large-diameter pieces that look like 1.5 to 5 inches (38 to 127 mm)-diameter wooden poker chips. Most kava plants consist of approximately 80% crown root upon harvesting. Lateral roots are smaller-diameter roots that look more like a typical root. A mature kava plant is about 20% lateral roots. Kava lateral roots have the highest content of kavalactones in the kava plant. "Waka" grade kava is made of lateral roots only.
== January 23, 1982 (Saturday) == In the U.S., the CBS television network broadcast The Uncounted Enemy: A Vietnam Deception, a 90-minute investigative documentary alleging that General William Westmoreland and other officials had suppressed and altered estimates of the actual troop strength of the Viet Cong within South Vietnam during the Vietnam War. U.S. Army Chief of Staff, General William Westmoreland during the war, and commander of U.S. troops in South Vietnam, was accused of manipulating the estimates of the number of communist infiltrators, and would file a $20 million lawsuit for libel on September 13, 1982, against the CBS network, as well as producer George Crile II, narrator Mike Wallace and former CIA analyst Samuel A. Adams. Australian thoroughbred horse trainer Colin Hayes, set a world record as horses he had trained finished in first place in 10 races, seven at Victoria Park in Adelaide and three others at Caulfield race track, on the same day."Big stable in a haze over all that success", by Glenn Lester, The Age (Sydney), January 25, 1982, p. 27 Died: Leonard Sillman, 72, U.S. Broadway theatre producer known for his discovery and introduction of new acting stars, including Henry Fonda, Imogene Coca, and Paul Lynde. Hope Hampton, 84, American opera soprano, silent film actress, and socialite "Hope Hampton, Opera Singer and First-Nighter, Dies at 84", by Joyce Purnick, The New York Times January 24, 1982, p. I-28
== Prevention == Key prevention strategies for cirrhosis are population-wide interventions to reduce alcohol intake (through pricing strategies, public health campaigns, and personal counseling), programs to reduce the transmission of viral hepatitis, and screening of relatives of people with hereditary liver diseases. Little is known about factors affecting cirrhosis risk and progression. However, many studies have provided increasing evidence for the protective effects of coffee consumption against the progression of liver disease. These effects are more noticeable in liver disease that is associated with alcohol use disorder. Coffee has antioxidant and antifibrotic effects. Caffeine may not be the important component; polyphenols may be more important. Drinking two or more cups of coffee a day is associated with improvements in the liver enzymes ALT, AST, and GGT. Even in those with liver disease, coffee consumption can lower fibrosis and cirrhosis.
== Awards and honors == Ben-Tal was awarded the Abraham E. Kazan Chair of Structural Biology at Tel Aviv University in 2018. He was also a recipient, with collaborators, of the 2018 NATO Science for Peace and Security Programme Partnership Prize for the project on the Bacillus anthracis MntABC transporter.
Sources: en.wikipedia.org
Most published work uses intranasal application, either as drops or as a nasal spray. Injection routes appear in a smaller set of animal experiments. Oral use is uncommon in the literature because peptide breakdown and poor absorption limit this route.
Reported human trials are few, brief and originate mainly from one country. They describe effects on anxiety-related measures, but sample sizes are small and reporting is limited. The results are widely regarded as preliminary rather than confirmed.
Reverse-phase liquid chromatography is used to assess purity and separation of related impurities. Mass spectrometry confirms that the observed molecular mass matches the expected peptide. A certificate of analysis from the supplier is the usual document of record.
The most common approach combines reverse-phase liquid chromatography with mass spectrometry. Chromatography separates the components while mass spectrometry confirms the molecular mass. Peptide sequencing or tandem mass analysis can further verify the amino acid order.