GABA-A modulation comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Updated 2026-05-05. Numbers and descriptions here follow the published literature rather than marketing material.
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.
Selank is a synthetic heptapeptide developed in Russia. Its sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, a seven-residue chain built around the natural tetrapeptide tuftsin. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences first described the compound in the mid-1990s. The design combined the tuftsin core with an added Pro-Gly-Pro tail, a modification intended to extend the molecule's stability in biological fluids. Published work on the peptide has appeared mainly in Russian-language journals.
Reported activity for Selank centers on anxiolytic and nootropic effects. Russian clinical reports describe use in anxiety and in cognitive or attention-related complaints. Most of this evidence comes from studies conducted by the same research groups that developed the peptide. Independent replication in other countries remains limited, and no major Western regulatory agency has approved the compound for any indication. The gap between local reports and external verification is a recurring point in discussions of the peptide.
| Property | Value | Notes |
|---|---|---|
| Principal proposed target | GABA-A receptor complex | Hypothesis derived mainly from animal pharmacology |
| Common behavioral assay | Elevated plus maze | Rodent test for anxiety-like behavior |
| Reported molecular marker | Hippocampal BDNF expression | Measured by immunoassay or mRNA quantification |
| Typical dosing route | Intranasal | Chosen to reduce first-pass metabolism |
| Reported plasma half-life | Minutes | Based on limited peptide stability data |
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed as a stabilized analogue of tuftsin, a naturally occurring tetrapeptide fragment derived from the immunoglobulin heavy chain. The additional Pro-Gly-Pro segment at the carboxyl terminus is intended to slow enzymatic cleavage. The compound is usually described in the literature as a synthetic peptide with anxiolytic and cognitive-related activity, a label that reflects a research context rather than an approved therapeutic category.
Most published work on selank originates from a small number of research groups in the Russian Federation. A large share of that record appears in Russian-language journals, which limits access for readers who rely on English-indexed databases. Independent replication by laboratories outside the original research network is sparse in publicly available sources. This concentration of origin and language is a frequently noted feature when the compound is summarized in broader reviews of synthetic peptides.
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.
In fish and other wildlife, selenium is necessary for life but toxic in high doses. For salmon, the optimal selenium concentration is about 1 microgram selenium per gram of whole body weight. Much below that level, young salmon die from deficiency; much above, they die from toxic excess.
Later, the researchers compared a few mercaptoacyl amino acid inhibitors and concluded that the binding of the inhibitor to the enzyme involved a hydrogen bond between a donor site on the enzyme and the oxygen of the amide carbonyl, much like predicted for the substrates.
== Production scale == Centrifugal partition chromatography does not use any solid stationary phase, so it guarantees a cost-effective separation for the highest industrial levels. As opposed to countercurrent chromatography, it is possible to get very high flow rates (for example 10 liters / min) with active stationary phase ratio of >80%, which guarantees good separation and high productivity. As in centrifugal partition chromatography, material is dissolved, and loaded the column in mass / volume units, loading capability can be much higher than standard solid-liquid chromatographic techniques, where material is loaded to the active surface area of the stationary phase, which takes up less than 10% of the column. Industrial instrument like Gilson (Armen Instrument), Kromaton (Rousselet Robatel), RotaChrom Technologies (RotaChrom) differ from laboratory scale instruments by the applicable flow rate with satisfactory stationary phase retention (70–90%). LiLiChro's solution is no different from analytics, so it can be scaled up in a completely linear way, and the stationary phase retention is higher than 90% in every case. Industrial instruments have flow rates of multiple liter / minutes, while able to purify materials from 10 kg to tonnes per month. Operating the production scale equipment requires industrial volume solvent preparation (mixer/settler) and solvent recovery equipment.
Sources: en.wikipedia.org
=== Cancer === In a 2022 update of an earlier report, the United States Preventive Services Task Force recommended against the use of vitamin E supplements for the prevention of cardiovascular disease or cancer, concluding there was insufficient evidence to assess the balance of benefits and harms, yet also concluding with moderate certainty that there is no net benefit of supplementation. As for literature on different types of cancer, an inverse relationship between dietary vitamin E and kidney cancer and bladder cancer is seen in observational studies. A large clinical trial reported no difference in bladder cancer cases between treatment and placebo. An inverse relationship between dietary vitamin E and lung cancer was reported in observational studies, but a large clinical trial in male tobacco smokers reported no impact on lung cancer between treatment and placebo, and a trial which tracked people who chose to consume a vitamin E dietary supplement reported an increased risk of lung cancer for those consuming more than 215 mg/day. For prostate cancer, there are also conflicting results. A meta-analysis based on serum alpha-tocopherol content reported an inverse correlation in relative risk, but a second meta-analysis of observational studies reported no such relationship. A large clinical trial with male tobacco smokers and reported a 32% decrease in the incidence of prostate cancer, but the SELECT trial of selenium or vitamin E for prostate cancer enrolled men ages 55 or older and reported relative risk 17% higher for the vitamin group.
== See also == 2026 deaths in the US 2026 in American music 2026 in American television List of American films of 2026 List of animated feature films of 2026 2026 NFL season 2026–27 NHL season 2026–27 NBA season 2026 Major League Baseball season
== Definition == Natural uranium contains about 0.72% 235U. Depleted uranium has lower mass fractions—up to three times less—of 235U and 234U than natural uranium. Since 238U has a much longer half-life than the lighter isotopes, DU is about 40% less radioactive than natural uranium. Most of the alpha radiation comes from 238U and 234U whereas beta radiation comes from decay products 234Th and 234Pa that are formed within a few weeks. The United States Nuclear Regulatory Commission (NRC) defines depleted uranium as uranium with a percentage of the 235U isotope that is less than 0.711% by weight (see 10 CFR 40.4). The military specifications designate that the DU used by the U.S. Department of Defense (DoD) contain less than 0.3% 235U. In actuality, DoD uses only DU that contains approximately 0.2% 235U.
Sources: en.wikipedia.org
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.
Behavioral endpoints include time spent in open arms of the elevated plus maze and avoidance latencies. Biochemical endpoints include BDNF concentration, cytokine levels, and monoamine metabolite ratios in brain tissue.
Most published studies are small, originate from a limited number of laboratories, and lack independent replication. Dose-response relationships, measured brain exposure, and long-term outcomes are not well characterized.
Selank is a synthetic peptide made of seven amino acids. It is modeled on tuftsin, a natural tetrapeptide, with an added three-residue tail. It is not a small-molecule drug.