Everything below concerns BDNF. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2025-09-16. Where a claim depends on a specific study, the study is described rather than over-claimed.
The compound has a calculated molecular weight near 751.9 daltons and carries a net positive charge at physiological pH because of its arginine residue. It dissolves freely in water and in common aqueous buffers, and typically appears as a white or off-white lyophilized powder. The amide backbone makes the molecule susceptible to peptidases, which limits oral use and favors intranasal or parenteral routes. Nomenclature in the literature varies: the substance is also described by the sequence abbreviation TP-7 and by a Russian trade designation.
Regulatory status differs sharply by region. Selank holds a Russian marketing authorization, where it is supplied mainly as nasal drops, while authorities elsewhere have not approved it for medical use. Material sold internationally is therefore usually labeled as a research chemical rather than a medicine. Peer-reviewed publications come predominantly from Russian laboratories, and sample sizes are generally small. Whether the compound produces comparable effects under independent, well-controlled replication remains an open question that the broader literature has not settled.
Selank is a synthetic heptapeptide developed in Russia as a structural analogue of tuftsin, a naturally occurring immunomodulatory tetrapeptide. Its sequence, Thr-Lys-Pro-Arg-Pro-Gly-Pro, keeps the tuftsin core at the N-terminus and appends a Pro-Gly-Pro tail. Researchers at the Institute of Molecular Genetics in Moscow synthesized the compound during the 1990s while searching for peptides with combined anxiolytic and immunomodulatory activity. The added tail was intended to resist enzymatic cleavage and prolong the molecule's presence in circulation.
Selank is studied chiefly as an animal-model anxiolytic with proposed secondary effects on memory and immune signaling. Reported mechanisms include modulation of the GABA-A receptor complex, inhibition of enkephalin-degrading enzymes, and shifts in monoamine turnover within limbic structures. Some experiments describe increased expression of brain-derived neurotrophic factor in the hippocampus after repeated dosing. No single molecular target has been confirmed, and the peptide does not bind any receptor with the selectivity typical of a conventional small-molecule drug. Mechanism therefore remains a set of hypotheses rather than an established pathway.
Laboratory work relies on standard behavioral paradigms. Rodents are tested in the elevated plus maze, open field, and passive avoidance tasks, with outcomes compared against diazepam or vehicle controls. Intranasal dosing is used most often because it bypasses first-pass metabolism, though intraperitoneal and intravenous routes also appear in published protocols. Biochemical endpoints include tissue BDNF concentrations, cytokine levels, and monoamine metabolites. Human data are limited to small Russian trials reporting reduced anxiety scores; most were not prospectively registered, and few employed independent outcome assessment.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Analog of the tetrapeptide tuftsin |
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Reported consistently across pharmacopoeial descriptions |
| Appearance | White to off-white lyophilized powder | Typical form of research-grade material |
| Solubility | Freely soluble in water | Aqueous buffers; poor in nonpolar solvents |
| Typical storage temperature | -20 degrees Celsius | Lyophilized powder; protect from moisture |
Purity assessment relies mainly on reverse-phase high-performance liquid chromatography with ultraviolet detection. Because the peptide lacks a strong chromophore, detection often uses backbone absorbance near 214 nm. Identity is confirmed by mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, comparing the measured mass against the expected value. Amino acid analysis can verify composition after acid hydrolysis. Diastereomer content and residual counterions are reported less often, although both can influence biological assays.
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.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter notation. Its structure consists of the immunomodulatory tetrapeptide tuftsin, Thr-Lys-Pro-Arg, extended at the carboxyl terminus by a Pro-Gly-Pro segment. The molecular formula is commonly given as C33H57N11O9, corresponding to a monoisotopic mass near 751.4 Da and an average molecular mass near 751.9 Da. All seven residues are proteinogenic amino acids, and the molecule carries no modified side chains or non-natural linkages.
The compound was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences during the 1980s and 1990s. The stated design goal was to retain the immunomodulatory and central nervous system activity attributed to tuftsin while improving resistance to enzymatic breakdown. Adding a proline-rich tail to the short parent peptide was a deliberate strategy, because proline residues restrict the conformations available to many peptidases. The same laboratory produced Semax, an ACTH fragment analog, and both compounds were developed in parallel as short, enzymatically stabilized peptides intended for intranasal use.
Pharmacokinetic data are limited. Like most short peptides, Selank is vulnerable to plasma and tissue peptidases, and its measured half-life in circulation is short, on a minutes scale. The Pro-Gly-Pro tail slows this degradation but does not eliminate it. Intranasal administration is the route described in most reports, with absorption through the nasal mucosa and a hypothesized path into the central nervous system that avoids the blood-brain barrier. Direct measurements of human brain exposure are unavailable, so distribution claims rest on inference from animal work.
Clinical evidence comes mainly from small studies conducted in Russia, several of which were open-label or lacked robust blinding. Reported outcomes include lower anxiety scores, changes in attention measures, and effects on asthenic states following illness. Sample sizes are typically in the tens of participants, and independent replication outside the region is scarce. Reviews published in English generally note the limited methodological quality of the underlying trials. Whether the compound produces clinically meaningful effects under rigorous conditions remains unresolved.
Identity and purity of selank are established with reversed-phase high-performance liquid chromatography coupled to mass spectrometry. The peptide elutes from C18 columns with acetonitrile gradients in water containing trifluoroacetic acid or formic acid, and detection is usually performed by ultraviolet absorbance near 214 nm. Electrospray ionization in positive mode gives a doubly protonated ion near m/z 377, consistent with a mass of about 752 Da. Amino acid analysis or tandem mass spectrometry of fragment ions confirms the sequence. Because the molecule has no aromatic residues, it lacks a usable 280 nm chromophore, so low-wavelength detection or mass spectrometry is required.
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.
A new format concept, A&W Great Food Restaurants, was developed. Ten corporate-owned locations were opened to test the concept: a sit-down, upscale, family-theme restaurant with a large salad bar and homemade ice cream. The first such branch opened in 1978 (1979, according to some sources) at the Lake Forest Shopping Mall in Gaithersburg, Maryland. Emphasis in these restaurants was made on low-calorie foods that covered almost the entirety of the foods found in the fast-food spectrum, except pizza. By 1986, there were plans to have 250 to 300 locations within ten years.
=== Netherlands === In 2007, four food technology students in the Netherlands invented a powdered alcohol product called "Booz2go". They claimed that when mixed with water, the powder would produce a bubbly, lime-colored and lime-flavored drink, with 3% alcohol. When put into commercial production, it was expected to sell for €1.50 (approx. US$1.60) for a 20 gram sachet. The product's creators and marketers – Harm van Elderen, Martyn van Nierop, and others at Helicon Vocational Institute in Boxtel – claimed to be aiming at the youth market. They compared the drink to alcopops like Bacardi Breezer and said they expected the relatively low alcohol content would be popular with the young segment. Because of complexities in Dutch laws, powdered alcohol like Booz2Go would not be subject to the Alcohol and Horeca Code, because it is not literally an alcoholic drink. This means that anybody of any age could buy it legally. However, when dissolved in water, it would be subject to the Code, according to Director Wim van Dalen of the Dutch National Foundation for Alcohol Prevention. Von Dalen commented that while he generally did not support new alcoholic drinks, he doubted the powder would become attractive. A spokesman of the Ministry of Health, Welfare and Sport said they would not undertake any actions against the product, but added that the label would have to contain a warning about any health risks for the consumer, in accordance with other laws. In 2014, Booz2go is not yet commercially available.
== Properties == Vitamers often have subtly different properties from their primary, or most common form. These differences include abundance in the typical diet, bioavailability, toxicity, physiological activities, and metabolism. Some vitamers are associated with different benefits for health compared to other forms of the same vitamin. Folic acid, a vitamer of vitamin B9 commonly added to fortified foods and dietary supplements, is 0.7–1.0 times more bioavailable than vitamers of vitamin B9 found in minimally processed foods. Differences in digestion and absorption account for the notable differences in bioavailability between vitamers of vitamin B9. Forms of vitamin B9 that occur in minimally processed foods, sometimes referred to as "food folates", require digestion by enzymatic hydrolysis prior to absorption whereas folic acid does not. Some vitamins have toxic effects when consumed in excess amounts and certain vitamers have a greater potential for toxicity compared to other forms of the same vitamin. For example, hypervitaminosis A is a toxicity syndrome caused by excess consumption of retinoid vitamers of vitamin A such as retinol, retinal, and retinoic acid. In contrast, provitamin A carotenoids such as beta-carotene are not associated with these toxic effects. Nicotinic acid and nicotinamide are two vitamers of vitamin B3 that exhibit differences in metabolism. Large, pharmaceutical doses of the nicotinic acid are used under medical supervision as a treatment for hypercholesterolemia.
Sources: en.wikipedia.org
By the 18th century, Cossack hosts in the Russian Empire occupied effective buffer zones on its borders. The expansionist ambitions of the Empire relied on ensuring Cossack loyalty, which caused tension given their traditional exercise of freedom, democracy, self-rule, and independence. Cossacks such as Stenka Razin, Kondraty Bulavin, Ivan Mazepa and Yemelyan Pugachev led major anti-imperial wars and revolutions in the Empire in order to abolish slavery and harsh bureaucracy, and to maintain independence. The Empire responded with executions and tortures, the destruction of the western part of the Don Cossack Host during the Bulavin Rebellion in 1707–1708, the destruction of Baturyn after Mazepa's rebellion in 1708, and the formal dissolution of the Lower Dnieper Zaporozhian Host after Pugachev's Rebellion in 1775. After the Pugachev rebellion, the Empire renamed the Yaik Host, its capital, the Yaik Cossacks, and the Cossack town of Zimoveyskaya in the Don region to try to encourage the Cossacks to forget the men and their uprisings. It also formally dissolved the Lower Dnieper Zaporozhian Cossack Host, and destroyed their fortress on the Dnieper (the Sich itself). This may in part have been due to the participation of some Zaporozhian and other Ukrainian exiles in Pugachev's rebellion. During his campaign, Pugachev issued manifestos calling for restoration of all borders and freedoms of both the Polish–Lithuanian Commonwealth and the Lower Dnieper (Nyzovyi in Ukrainian) Cossack Host under the joint protectorate of Russia and the Commonwealth.
=== Alcohol use === GGT is elevated by ingestion of large quantities of alcohol. However, determination of high levels of total serum GGT activity is not specific to alcohol intoxication, and the measurement of selected serum forms of the enzyme offer more specific information. Isolated elevation or disproportionate elevation compared to other liver enzymes (such as ALT or alanine transaminase) can indicate harmful alcohol use or alcoholic liver disease, and can indicate excess alcohol consumption up to 3 or 4 weeks prior to the test. The mechanism for this elevation is unclear. Alcohol might increase GGT production by inducing hepatic microsomal production, or it might cause the leakage of GGT from hepatocytes.
Maurice Loyal Huggins (September 19, 1897, Berkeley, California – December 17, 1981) was a scientist who independently conceived the idea of hydrogen bonding and who was an early advocate for their role in stabilizing protein secondary structure. An important polymer theory, Flory–Huggins theory, is also named after him.
Sources: en.wikipedia.org
Currently there is no universal method to overcome the problems of delivery, cell uptake and endosomal escape, but there exist several approaches which are tailored to specific cells and their receptors. A conjugation of ON therapeutics to an entity responsible for cell recognition/uptake not only increases the uptake (vide supra) but is also believed to decrease the complexity of the cell uptake as mainly one (ideally known) mechanism is then involved. This has been achieved with small molecule-ON conjugates for example bearing an N-acetyl galactosamine which targets receptors of hepatocytes. These conjugates are an excellent example for obtaining an increased cell uptake paired with targeted delivery as the corresponding receptors are overexpressed on the target cells leading to a targeted therapeutic (compare antibody-drug conjugates which exploit overexpressed receptors on cancer cells). Another broadly used and heavily investigated entity for targeted delivery and increased cell uptake of oligonucleotides are antibodies.
Nonetheless, ECB Vice President Luis de Guindos stated that central bank liquidity swap lines between the Federal Reserve and the ECB remained "business as usual". International Monetary Fund Director Kristalina Georgieva also spoke in defense of Powell and the Federal Reserve's independence given the role of the United States dollar as the world's reserve currency.
) without multiplying by 1000 unless the basic SI unit of mol/s were to be used, which would otherwise require the molar mass to be converted to kg/mol. For convenience in avoiding conversions in the imperial (or US customary units), some engineers adopted the pound-mole (notation lb-mol or lbmol), which is defined as the number of entities in 12 lb of 12C. One lb-mol is equal to 453.59237 g‑mol, which is the same numerical value as the number of grams in an international avoirdupois pound. Greenhouse and growth chamber lighting for plants is sometimes expressed in micromoles per square metre per second, where 1 mol photons ≈ 6.02×1023 photons. The obsolete unit einstein is variously defined as the energy in one mole of photons and also as simply one mole of photons.
Sources: en.wikipedia.org
Selank is a synthetic seven-amino-acid peptide modeled on tuftsin, a fragment of the immunoglobulin G heavy chain. It was designed in Russia to combine anxiolytic and immunomodulatory properties in one molecule.
The first four residues of Selank reproduce the tuftsin sequence Thr-Lys-Pro-Arg. A Pro-Gly-Pro extension at the C-terminus was added to slow enzymatic breakdown and extend residence time.
It holds marketing authorization in Russia, where nasal drop formulations are sold. No equivalent approval exists in the European Union, the United States, or most other countries.
Intranasal administration predominates in both animal and human research because it avoids hepatic first-pass metabolism. Injectable and intraperitoneal routes appear in animal work mainly for comparison.