If you have been reading about Selank and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2026-03-14. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Quantification in biological matrices relies on liquid chromatography coupled to tandem mass spectrometry with stable-isotope internal standards. Low plasma concentrations and adsorption to container surfaces both complicate measurement. Solid-phase extraction is often needed to reduce matrix interference before injection. Reported limits of quantification differ widely between laboratories, which makes direct comparison of pharmacokinetic results difficult and limits meta-analysis.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Dry storage temperature | -20 C or below | Sealed, desiccated, protected from light |
| Solution stability | Hours to days at 2-8 C | Depends on buffer and microbial load |
| Preferred pH range | Near neutral to slightly acidic | Alkaline pH accelerates hydrolysis |
| Main degradation routes | Hydrolysis and deamidation | No cysteine or methionine in sequence |
| Identity confirmation | Electrospray mass spectrometry | Observed mass compared with 751.9 Da |
Selank is a synthetic heptapeptide developed in Russia during the 1990s. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences designed it as a stabilized analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The compound has been studied primarily for its reported anxiolytic and nootropic effects. It remains largely unknown in Western pharmacology and is not approved as a medicine by major regulators such as the FDA or the EMA.
The primary structure of Selank is Thr-Lys-Pro-Arg-Pro-Gly-Pro, corresponding to the molecular formula C33H57N11O9 and a monoisotopic mass of roughly 751.9 daltons. The N-terminal threonine and the arginine residue in the fourth position are shared with tuftsin, which carries the sequence Thr-Lys-Pro-Arg. The three additional residues at the C-terminus, Pro-Gly-Pro, extend the chain and are associated with greater resistance to enzymatic degradation. This extension also separates Selank from the shorter parent peptide.
Proposed mechanisms centre on modulation of the GABAergic system, with reports of altered expression of genes related to GABA-A receptor subunits and changed monoamine turnover. Some studies describe inhibition of enkephalinase, the enzyme that degrades endogenous enkephalins, which may prolong opioid peptide signalling. Effects on brain-derived neurotrophic factor and on cytokine expression have also been reported. These findings come largely from animal models and small human studies, and the precise primary target remains unresolved.
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.
== Medical devices == A variety of medical devices are in use or under consideration for treatment of depression including devices that offer electroconvulsive therapy, vagus nerve stimulation, repetitive transcranial magnetic stimulation, and cranial electrotherapy stimulation. The use of such devices in the United States requires approval by the U.S. Food and Drug Administration (FDA) after field trials. In 2010 an FDA advisory panel considered the question of how such field trials should be managed. Factors considered were whether drugs had been effective, how many different drugs had been tried, and what tolerance for suicides should be in field trials.
Several of the Union Republics themselves, most notably Russia, were further subdivided into Autonomous Soviet Socialist Republics (ASSRs). Though administratively part of their respective Union Republics, ASSRs were also established based on ethnic/cultural lines. On April 3, 1990, a law was passed which stated that when a union republic was voting to leave the Soviet Union, autonomous republics, autonomous oblasts, and autonomous okrugs had the right, by means of a referendum, to independently resolve whether they would stay in the USSR or leave with the seceding union republic, as well as broader rights to raise the issue of their state-legal status.
The hemoglobin is metabolized to bilirubin (causing jaundice at high concentrations). The red cells rarely disintegrate in the circulation, so hemoglobin is rarely excreted directly by the kidney, but this can occur in severe cases, causing acute kidney injury. Deficiency of G6PD in the alternative pathway causes the buildup of glucose, and thus an increase of advanced glycation endproducts (AGE). The deficiency also reduces the amount of NADPH, which is required for nitric oxide (NO) synthesis. The high prevalence of diabetes mellitus type 2 and hypertension in Afro-Caribbeans in the West could be directly related to the incidence of G6PD deficiency in those populations. Although female carriers can have a mild form of G6PD deficiency (dependent on the degree of inactivation of the unaffected X chromosome – see Skewed X-inactivation), homozygous females have been described; in these females, there is co-incidence of a rare immune disorder termed chronic granulomatous disease (CGD).
=== Combinatorial selection of RNA molecules enables in vitro evolution === Experimental methods were invented that allowed investigators to use large, diverse populations of RNA molecules to carry out in vitro molecular experiments that utilized powerful selective replication strategies used by geneticists, and which amount to evolution in the test tube. These experiments have been described using different names, the most common of which are "combinatorial selection", "in vitro selection", and SELEX (for Systematic Evolution of Ligands by Exponential Enrichment). These experiments have been used for isolating RNA molecules with a wide range of properties, from binding to particular proteins, to catalyzing particular reactions, to binding low molecular weight organic ligands. They have equal applicability to elucidating interactions and mechanisms that are known properties of naturally occurring RNA molecules to isolating RNA molecules with biochemical properties that are not known in nature. In developing in vitro selection technology for RNA, laboratory systems for synthesizing complex populations of RNA molecules were established, and used in conjunction with the selection of molecules with user-specified biochemical activities, and in vitro schemes for RNA replication. These steps can be viewed as (a) mutation, (b) selection, and (c) replication. Together, then, these three processes enable in vitro molecular evolution.
Sources: en.wikipedia.org
== Firearms == In June 2018, the Small Arms Survey released a briefing paper entitled "Estimating Global Civilian-Held Firearms". The paper estimates that the total number of guns, both licit and illicit, held by Thai civilians in 2017 was 10,300,000, equating to 15.1 firearms per 100 inhabitants. Comparable figures for other ASEAN nations are: Cambodia, 4.5 per 100 inhabitants; the Philippines, 3.6; Laos, 3.0; Myanmar, 1.6; Vietnam, 1.6; Brunei, 1.4; Malaysia, 0.7; Singapore, 0.3; and Indonesia, zero.
==== Structure ==== Like other eukaryotic cells, animal cells are made up of a cell membrane containing a gel like cytoplasm. In this cytoplasm are a variety of membrane organelles, including all the shared eukaryotic organelles: the cell nucleus, the endoplasmic reticulum, ribosomes, the Golgi apparatus, mitochondria, peroxisomes, endosomes, vacuoles and vesicles, and vaults; as well and centrosomes, which are unique to animal cells.
The two substrates of this enzyme are dihydrophloroglucinol (1) and oxidised nicotinamide adenine dinucleotide phosphate (NADP+). Its products are phloroglucinol (2), reduced NADPH, and a proton. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-CH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is dihydrophloroglucinol:NADP+ oxidoreductase. This enzyme participates in benzoate degradation via CoA ligation.
Sources: en.wikipedia.org
=== Synthesis based on hydrogen cyanide === A research project completed in 2015 by John Sutherland and others found that a network of reactions beginning with hydrogen cyanide and hydrogen sulfide, in streams of water irradiated by UV light, could produce the chemical components of proteins and lipids, as well as those of RNA, while not producing a wide range of other compounds. The researchers used the term "cyanosulfidic" to describe this network of reactions.
== Causes == Bronchiolitis obliterans has many possible causes, including collagen vascular disease, transplant rejection in organ transplant patients, viral infection (adenovirus, respiratory syncytial virus, influenza, HIV, cytomegalovirus), Stevens–Johnson syndrome, Pneumocystis pneumonia, drug reaction, aspiration and complications of prematurity (bronchopulmonary dysplasia), and exposure to toxic fumes. Toxins implicated in the condition include diacetyl, sulfur dioxide, nitrogen dioxide, ammonia, chlorine, thionyl chloride, methyl isocyanate, hydrogen fluoride, hydrogen bromide, hydrogen chloride, hydrogen sulfide, phosgene, polyamide-amine dyes, mustard gas and ozone. It can also be present in patients with IBD, systemic lupus erythematosus, juvenile idiopathic arthritis, rheumatoid arthritis, GERD, IgA nephropathy, and ataxia telangiectasia. Activated charcoal has been known to cause it when aspirated. The ingestion of large doses of papaverine in the vegetable Sauropus androgynus has caused it. Additionally, the disorder may be idiopathic (without known cause).
The high-resolution atomic structure, molecular physiology and subcellular compartmentation of creatine kinase (CK) isoenzymes (https://pubmed.ncbi.nlm.nih.gov/10737943/), (https://pubmed.ncbi.nlm.nih.gov/10595529/) and (https://pubmed.ncbi.nlm.nih.gov/10737943/) and of the Creatine Transporter (CRT), and in general, micro-compartmentation and metabolite channeling by multi-enzyme complexes. The mechanisms of the cell enhancing and neuro-protective effects of creatine supplementation in health (muscle strength, learning and memory) and disease (neuromuscular and neuro-degenerative disorders).(see the recent Conference Volume on "Creatine Supplementation for Health and Clinical Diseases" (2022) https://exerciseandsportnutritionlab.com/news/creatine-in-health-book-published/ The structure and molecular physiology of AMP-activated protein kinase (AMPK), involved in cellular energy homeostasis and nutritional signalling, which is relevant for type-2 diabetes, obesity, metabolic syndrome and cancer.(for publications in PubMed see: and ).
=== Bag of cement and bag mix === The mass of an old bag of cement was one hundredweight (112 pounds, 51 kg). In the concrete and petroleum industry, however, a bag of cement is defined as 94 lb (43 kg) because it has an apparent volume close to 1 cubic foot (28 litres).
Sources: en.wikipedia.org
Dry powder is best kept sealed, protected from light, and held at minus 20 degrees Celsius or below. Desiccant packaging helps limit moisture uptake because the material is hygroscopic. A sealed vial should be allowed to equilibrate to room temperature before opening to reduce condensation.
Hydrolysis of peptide bonds and deamidation of arginine and proline residues are the main degradation routes. Alkaline pH and higher temperatures accelerate both processes. Buffered, near-neutral solutions stored cold generally degrade more slowly than unbuffered ones.
Reverse-phase chromatography gives the clearest single view of related impurities and truncated sequences. Mass spectrometry then confirms that the main peak carries the expected mass. Neither test detects enantiomeric impurities, which require a separate chiral assay.
Reports describe effects on GABA-A receptor expression, monoamine turnover, and neurotrophic factor levels. These are proposed mechanisms drawn mainly from animal models. No single molecular target has been established.