Selank 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.
Last reviewed on 2026-08-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
Reversed-phase high-performance liquid chromatography is the standard technique for estimating peptide purity. The result is a peak-area percentage, which describes how much of the detected material elutes as the main peak in one run. Mass spectrometry confirms the molecular mass and can reveal truncated, adducted, or otherwise modified species. Amino acid analysis or tandem mass spectrometry can address sequence fidelity when identity is in doubt. None of these measurements, taken alone, establishes that a sample is fit for any specific purpose.
Lyophilized selank is normally supplied as a dry powder and is considered stable for extended periods when kept cold and dry. Moisture uptake is the main practical threat, because absorbed water promotes both hydrolysis and aggregation in the solid state. Vials are usually warmed to room temperature before opening so that condensation does not form on the powder. Supplier documentation commonly specifies -20 °C for routine storage, with -80 °C used for material intended to be archived for years.
Once dissolved, the peptide is markedly less stable than the dry powder. Aqueous solutions are subject to backbone hydrolysis and to microbial growth when they are handled without sterile technique. Buffered solutions near neutral pH are common for short-term laboratory work, while acidic conditions are sometimes used to improve solubility. Analytical laboratories generally prepare working solutions fresh rather than storing them, and a residual water film left in a reopened vial can seed degradation even when the container appears dry.
| Property | Value | Notes |
|---|---|---|
| Typical purity report | 95% or higher by HPLC | Area percentage at 214 nm |
| Identity confirmation | Mass spectrometry | Electrospray or MALDI |
| Powder storage | -20 C, desiccated | Protect from light |
| Solution storage | 2-8 C short term | Freeze aliquots for longer |
| Quality document | Certificate of analysis | States method and value |
Published clinical evidence is limited. Most controlled trials were conducted in Russia, enrolled modest numbers of participants, and appeared in Russian-language journals, which restricts independent verification. Reported outcomes include lower anxiety scores, improved attention and memory measures, and changes in fatigue ratings. Reviews written in English note methodological limitations such as small samples and inconsistent endpoints. Whether the compound produces clinically meaningful benefit relative to established anxiolytics is therefore an open question rather than an established finding.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences as a structural analogue of tuftsin, a naturally occurring tetrapeptide fragment of the immunoglobulin heavy chain. The added Pro-Gly-Pro tail was intended to slow enzymatic degradation and extend biological activity. In Russia it is registered as an anxiolytic nasal preparation, while regulators elsewhere have not approved it for clinical use.
Development work on the compound began in the 1980s and 1990s at the Institute of Molecular Genetics in Moscow, within the same research programme that produced the peptide Semax. Early investigators sought a tuftsin derivative with improved resistance to enzymatic breakdown and with activity in the central nervous system after peripheral administration. Most of the primary literature from this period was published in Russian, a factor that still shapes how easily the findings can be checked by outside groups.
Naming for this compound is not fully standardised in English sources. The spelling Selanc appears in some transliterations, and catalogue entries may instead list the peptide sequence itself as the identifier. Reference material sometimes groups it with other short synthetic peptides studied for behavioural effects, which can create confusion when citations are compared. Distinguishing the exact sequence from related tuftsin analogues is therefore a practical first step when reviewing any dataset or specification sheet.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, frequently abbreviated as TKPRPGP. It was designed as a structural analogue of tuftsin, a naturally occurring tetrapeptide released by enzymatic cleavage of the immunoglobulin heavy chain. The two additional proline residues at the C-terminal end extend the parent chain and change how the molecule behaves in solution. The free peptide has a calculated molecular mass of approximately 751.9 g/mol and is generally supplied as a lyophilised white to off-white powder.
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.
=== Precursor === The Gag-Pol polyprotein, which contains premature coding proteins, including HIV-1 PR. PR is located between the reverse transcriptase (which is at the C-terminus of PR) and the p6pol (which is at the N-terminus of PR) of the transframe region (TFR). In order for this precursor to become a functional protein, each monomer must associate with another HIV-1 PR monomer to form a functional catalytic active site by each contributing the Asp25 of their respective catalytic triads.
Repotrectinib, sold under the brand name Augtyro, is an anti-cancer medication used for the treatment of non-small cell lung cancer. It is taken by mouth. Repotrectinib is an inhibitor of proto-oncogene tyrosine-protein kinase ROS1 (ROS1) and of the tropomyosin receptor tyrosine kinases (TRKs) TRKA, TRKB, and TRKC. The most common adverse reactions include dizziness, dysgeusia, peripheral neuropathy, constipation, dyspnea, ataxia, fatigue, cognitive disorders, and muscular weakness. Repotrectinib was approved for medical use in the United States in November 2023, and in the European Union in January 2025.
Thus, the person's blood clots too readily, and he is perpetually at an increased risk for thrombosis. Individuals heterozygous for the Factor VLeiden mutation carry a risk of venous thrombosis 5–7 times higher than in the general population. Homozygous subjects have a risk 80 times higher. This mutation is also the most common hereditary risk for venous thrombosis among Caucasians. Around 5% of APC resistance are not associated with the above mutation and Factor VLeiden. Other genetic mutations cause APC resistance, but none to the extent that Factor VLeiden does. These mutations include various other versions of Factor V, spontaneous generation of autoantibodies targeting Factor V, and dysfunction of any of APC's cofactors. Also, some acquired conditions may reduce the efficacy of APC in performing its anticoagulative functions. Studies suggest that between 20% and 60% of thrombophilic patients suffer from some form of APC resistance. Warfarin necrosis is an acquired protein C deficiency due to treatment with warfarin, which is a vitamin K antagonist and an anticoagulant itself. However, warfarin treatment may produce paradoxical skin lesions similar to those seen in purpura fulminans. A variant of this response presents as venous limb gangrene when warfarin is used to treat deep vein thrombosis associated with cancer. In these situations, warfarin may be restarted at a low dosage to ensure that the protein C deficiency does not present before the vitamin K coagulation factors II, IX and X are suppressed.
Polymers for which UCST relies on non-ionic interactions are very sensitive to ionic contamination. Small amounts of ionic groups may suppress phase separation in pure water. The UCST is dependent on the molecular mass of the polymer. For the LCST this is not necessarily the case, as shown for poly(N-isopropylacrylamide).
== M == M13 phage - m7G(5')pppN diphosphatase - malformation - maltose-transporting ATPase - manganese-transporting ATPase - mannose-6-phosphate 6-reductase - mapping - marker - melanoma - melting - menaquinol oxidase (H+-transporting) - Johann Mendel - Mendelian inheritance - message - messenger RNA - metaphase - methylphenyltetrahydropyridine N-monooxygenase - methylsterol monooxygenase - methyltetrahydroprotoberberine 14-monooxygenase - microarray technology - microsatellite - MIMT1 - minusheet perfusion culture system - Mir-188 microRNA precursor family - Mir-615 microRNA precursor family - Mir-675 microRNA precursor family - missense mutation - mitochondrial DNA - mobility shift - molecular weight size marker - monoclonal antibody - monosaccharide-transporting ATPase - monosomy - morphine 6-dehydrogenase - mouse model - mRNA - multicistronic message - multicopy plasmid - multiple cloning site - multiple endocrine neoplasia, type 1 - mutation - myristoyl-CoA 11-(E) desaturase - myristoyl-CoA 11-(Z) desaturase -
Sources: en.wikipedia.org
Biko and many others in his activist circle had an antipathy toward luxury items because most South African blacks could not afford them. He owned few clothes and dressed in a low-key manner. He had a large record collection and particularly liked gumba. He enjoyed parties, and according to his biographer Linda Wilson, he often drank substantial quantities of alcohol. Religion did not play a central role in his life. He was often critical of the established Christian churches, but remained a believer in God and found meaning in the Gospels. Woods described him as "not conventionally religious, although he had genuine religious feeling in broad terms". Mangcu noted that Biko was critical of organised religion and denominationalism and that he was "at best an unconventional Christian". The Nationalist government portrayed Biko as a hater of whites, but he had several close white friends, and both Woods and Wilson insisted that he was not a racist. Woods related that Biko "simply wasn't a hater of people", and that he did not even hate prominent National Party politicians like B. J. Vorster and Andries Treurnicht, instead hating their ideas. It was rare and uncharacteristic of him to display any rage, and was rare for him to tell people about his doubts and inner misgivings, reserving those for a small number of confidants. Biko never addressed questions of gender and sexism in his politics.
Rhodium is a fission product of uranium-235: each kilogram of fission product contains a significant amount of the lighter platinum group metals. Used nuclear fuel is therefore a potential source of rhodium, but the extraction is complex and expensive, and the presence of rhodium radioisotopes requires a period of cooling storage for multiple half-lives of the longest-lived isotope (101Rh with a half-life of 3.3 years, and 102mRh with a half-life of 2.9 years), or about 10 years. These factors make the source unattractive and no large-scale extraction has been attempted.
Comfrey, which contains alkaloids which may be harmful to the liver from chronic use, and particularly is not recommended during pregnancy or when prescription drugs are used; comfrey is not recommended for oral use. Lobelia, which contains alkaloids and has traditional medicine uses for smoking cessation, may cause nausea, vomiting, or dizziness at high doses. Herbal teas can also have different effects from person to person, and this is further compounded by the problem of potential misidentification. The deadly foxglove, for example, can be mistaken for the much more benign (but still relatively toxic to the liver) comfrey. Care must be taken not to use any poisonous plants. The US does not require herbal teas to have any evidence concerning their efficacy, but does treat them technically as food products and require that they be safe for consumption. Fruit or fruit-flavored tea is usually acidic and thus may contribute to erosion of tooth enamel.
==== Membranes ==== Cholesterol is present in varying degrees in all animal cell membranes but is absent in prokaryotes. It is required to build and maintain membranes and modulates membrane fluidity over the range of physiological temperatures. The hydroxyl group of each cholesterol molecule interacts with water molecules surrounding the membrane, as do the polar heads of the membrane phospholipids and sphingolipids, while the bulky steroid and the hydrocarbon chain are embedded in the membrane, alongside the nonpolar fatty-acid chain of the other lipids. Through the interaction with the phospholipid fatty-acid chains, cholesterol increases membrane packing, which both alters membrane fluidity and maintains membrane integrity so that animal cells do not need to build cell walls (like plants and most bacteria). The membrane remains stable and durable without being rigid, allowing animal cells to change shape and animals to move. The structure of the tetracyclic ring of cholesterol contributes to the fluidity of the cell membrane, as the molecule is in a trans conformation, making all but the side chain of cholesterol rigid and planar. In this structural role, cholesterol also reduces the permeability of the plasma membrane to neutral solutes, hydrogen ions, and sodium ions.
=== Amino-acid shuttles and the transport of ammonia === Since diffusion and transport of free ammonia across the cell membrane will affect the pH level of the cell, the more attractive and regulated way of transporting ammonia between the neuronal and the astrocytic compartment is via an amino-acid shuttle, of which there are two: leucine and alanine. The amino acid moves in the opposite direction of glutamine. In the opposite direction of the amino acid, a corresponding molecule is transported; for alanine this molecule is lactate; for leucine, α-ketoisocaproate.
Sources: en.wikipedia.org
Purity is usually reported as an HPLC area percentage, most often measured at 214 nm. Identity is confirmed separately by mass spectrometry. A certificate of analysis should state both the method and the observed value.
Dry powder is kept frozen, desiccated, and shielded from light. Dissolved material is aliquoted and frozen to limit freeze-thaw cycles. Short-term refrigerated storage is common for working solutions.
Russia registers it as a prescription nasal product. Most other markets classify it as a research chemical with no approved medical use. Oversight of purity and labeling is consequently minimal in those markets.
Sealed, desiccated storage at -20 °C or colder is the standard recommendation for research-grade material. Vials should reach room temperature before they are opened, which limits condensation. Repeated temperature cycling is discouraged.