Neurotrophic factor raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-06-14 and is reviewed periodically as new material appears.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Route studied | Intranasal | Predominant route in published reports |
| Circulation stability | Short, minutes scale | Peptidases cleave it; the tail slows the process |
| Analytical method | RP-HPLC with mass spectrometry | Used for identity and purity assessment |
| Reported outcome domains | Anxiety and cognitive measures | Derived from small, mostly regional trials |
| Regulatory status | Marketed in Russia | Availability outside that market is limited |
Development took place at the Institute of Molecular Genetics of the Russian Academy of Sciences, where a series of short peptides were designed in the 1980s and 1990s. Selank was selected from variants of tuftsin that showed resistance to plasma peptidases. Russian regulatory approval covers it as an anxiolytic agent given intranasally. Outside that market the compound is normally handled as a research chemical rather than a medicine, and no widely recognised international pharmacopoeial monograph exists. The name Selank is a coined trade designation rather than a systematic chemical name.
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 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.
IC50 / pIC50 values represent binding affinity only and do not reflect efficacy or pharmacokinetics, and some compounds listed are GABAA antagonists rather than agonists (e.g. flumazenil). Low IC50 or high pIC50 values indicate tighter binding (pIC50 of 8.0 = IC50 of 10nM, pIC50 of 9.0 = IC50 of 1nM, etc.) These are non subtype selective IC50 values averaged across all GABAA receptor subtypes, so subtype selective compounds with strong binding at one subtype but weak at others will appear unusually weak due to averaging of binding values (see e.g. CL-218,872) † indicates a predicted value from in silico modelling. Finally, note that the benzodiazepine core is a privileged scaffold, which has been used to derive drugs with diverse activity that is not limited to the GABAA modulatory action of the classical benzodiazepines, such as devazepide and tifluadom, however these have not been included in the list below. 2,3-benzodiazepines such as tofisopam are also not listed, as these act primarily as AMPA receptor modulators, and are inactive at GABAA receptors.
== Genetics == Hemoglobin consists of protein subunits (globin molecules), which are polypeptides, long folded chains of specific amino acids which determine the protein's chemical properties and function. The amino acid sequence of any polypeptide is translated from a segment of DNA, the corresponding gene. There is more than one hemoglobin gene. In humans, hemoglobin A (the main form of hemoglobin in adults) is coded by genes HBA1, HBA2, and HBB. Alpha 1 and alpha 2 subunits are respectively coded by genes HBA1 and HBA2 close together on chromosome 16, while the beta subunit is coded by gene HBB on chromosome 11. The amino acid sequences of the globin subunits usually differ between species, with the difference growing with evolutionary distance. For example, the most common hemoglobin sequences in humans, bonobos and chimpanzees are completely identical, with exactly the same alpha and beta globin protein chains. Human and gorilla hemoglobin differ in one amino acid in both alpha and beta chains, and these differences grow larger between less closely related species. Mutations in the genes for hemoglobin can result in variants of hemoglobin within a single species, although one sequence is usually "most common" in each species. Many of these mutations cause no disease, but some cause a group of hereditary diseases called hemoglobinopathies. The best known hemoglobinopathy is sickle-cell disease, which was the first human disease whose mechanism was understood at the molecular level.
Alice in Chains released their debut album, Facelift, in August 1990 through Columbia Records. Inspired by the music of Black Sabbath, Deep Purple, and Motörhead, the album was initially unsuccessful; the band's first live performances were local shows and festivals around Seattle. Their first tour came as a supporting act to Extreme for a month. Extreme themselves had yet to reach fame and were playing their first tour; neither band drew well. Alice in Chains followed with an opening slot on a tour with Iggy Pop in November 1990, but the band was similarly received with indifference. Their fortunes began to turn when the video for their breakout single, "Man in the Box", landed regular rotation on MTV, beating Blue Murder for a slot on the channel's "Buzz Bin". With newfound momentum, the group secured two supporting slots on two high-profile tours: first, they were selected to join thrash metal bands Anthrax, Megadeth, and Slayer, on the Clash of the Titans Tour in mid-1991, having replaced opening act Death Angel after the band was involved in a bus accident that left its drummer Andy Galeon critically injured and unable to perform. They were then appointed to a slot on Van Halen's For Unlawful Carnal Knowledge Tour later that year; Van Halen frontman Sammy Hagar personally selected the band. Sales of Facelift increased drastically, and by September 1991, it had been certified gold by the Recording Industry Association of America (RIAA).
Like agonists, inverse agonists have their own unique ways of inducing pharmacological and physiological responses depending on many factors, such as the type of inverse agonist, the type of receptor, mutants of receptors, binding affinities and whether the effects are exerted acutely or chronically based on receptor population density. Because of this, they exhibit a spectrum of activity below the Intrinsic activity level. Changes in constitutive activity of receptors affect response levels from ligands like inverse agonists. To illustrate, mechanistic models have been made for how inverse agonists induce their responses on G protein-coupled receptors (GPCRs). Many types of Inverse agonists for GPCRs have been shown to exhibit the following conventionally accepted mechanism. Based on the Extended Ternary complex model, the mechanism contends that inverse agonists switch the receptor from an active state to an inactive state by undergoing conformational changes. Under this model, current thinking is that the GPCRs can exist in a continuum of active and inactive states when no ligand is present. Inverse agonists stabilize the inactive states, thereby suppressing agonist-independent activity. However, the implementation of 'constitutively active mutants' of GPCRs change their intrinsic activity. Thus, the effect an inverse agonist has on a receptor depends on the basal activity of the receptor, assuming the inverse agonist has the same binding affinity (as shown in the figure 2).
An estimated 1,680 million people died of infectious diseases in the 20th century and about 10 million in 2010. The World Health Organization collects information on global deaths by International Classification of Disease (ICD) code categories. The following table lists the top infectious disease by number of deaths in 2002. 1993 data is included for comparison.
Sources: en.wikipedia.org
==== Other chemistry and biochemistry ==== Amalgam (chemistry), represented in medieval alchemical texts with "aaa" Asymmetric allylic alkylation α-Aminoadipate pathway, for the synthesis of the amino acid L-lysine AAA proteins (ATPases Associated with various cellular Activities)
Hunt Sahir Field in December 1971. In September 1973, all foreign oil producers in Libya saw 51 per cent of their operation nationalized. Among the companies that were partially nationalized was Armand Hammer's Occidental Petroleum. For Gaddafi, this was an essential step towards socialism. It proved an economic success; while gross domestic product had been $3.8 billion in 1969, it had risen to $13.7 billion in 1974, and $24.5 billion in 1979. In turn, Libyan standards of life greatly improved over the first decade of Gaddafi's administration, and by 1979 the average per-capita income was at $8,170, up from $40 in 1951; above that of many industrialized countries like Italy and the UK. In 1969, the government ordered all foreign owned banks to close down or convert to joint-stock operations.
=== Techniques to isolate specific genes === Gene identification can be accomplished using computer-based methods known as heterologous screening techniques. A digital library of cDNA sequences has data from many sequencing projects and allows for easy access to sequence information for known genes. If a genomic sequence is unknown or unavailable, DNA undergoes a process of random fragmentation, cloning, and screening to determine its phenotype. Although various methods can be used to obtain a particular gene, the easiest way to reveal the components of an unknown DNA sequence is by first identifying its restriction enzymes. Restriction enzymes are enzymes responsible for cleaving DNA into fragments at a specific site within molecules known as restriction sites. These enzymes can be located in bacteria or archaea and are known to protect DNA from foreign invasion of viruses. Restriction enzymes are distinct, and each recognizes only a specific sequence of base pairs within DNA, many of which tend to be palindromic. By locating each enzyme, the sequence associated with the restriction enzyme can be identified and isolated. If the sequence is known, a technique referred to as the Polymerase chain reaction (PCR) can be used to isolate a gene of interest. The purpose of PCR is to not only identify but to amplify a particular DNA segment through phases of denaturation, annealing, and extension. Denaturation places a double-stranded DNA template in high-temperature conditions of 95 °C to break its weak hydrogen bonds and enforce strand separation.
=== Endogenous role === DMT exists naturally in humans and other animals; it may play significant roles in mammalian physiology—potentially as a neurotransmitter, hormone, and immunomodulator—despite longstanding skepticism based on outdated or flawed evidence.
Sources: en.wikipedia.org
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.
Intranasal delivery is the route described in most published work. It is used because the peptide is degraded quickly once it reaches circulation. Direct evidence of brain penetration in humans is lacking.
Most trials are small, regionally concentrated, and often lack rigorous blinding or placebo control. Independent replication is limited. Reviews in English generally rate the evidence as preliminary.
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.