Regulatory peptide is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Updated 2025-09-16. Numbers and descriptions here follow the published literature rather than marketing material.
Animal studies have examined behaviour in tests of anxiety, memory retention and stress response, and several report changes in neurotrophic or neurotransmitter-related markers. The human evidence base is much smaller, consisting mainly of short trials conducted in Russia with limited reporting in English-language journals. Sample sizes are modest and outcome measures vary between studies, so the findings are best described as preliminary. Independent replication under modern trial standards has not been widely reported.
Outside its country of origin the compound is generally handled as a research chemical rather than an approved medicine. No regulatory approval from the United States Food and Drug Administration or the European Medicines Agency has been granted for human use. Identity and purity are normally checked by reverse-phase high-performance liquid chromatography, with mass spectrometry used to confirm the molecular mass. Lyophilised material is stored cold and desiccated, and repeated freeze-thaw cycles are avoided.
Published work on this peptide almost always uses intranasal delivery, with drops or a spray applied to the nasal mucosa. Some animal experiments have used subcutaneous or intraperitoneal injection, and a smaller number have compared routes directly. Oral administration is not a focus of the literature, because short peptides of this size are broken down by digestive enzymes and cross intestinal barriers poorly. How much of an intranasal dose reaches the bloodstream intact in humans remains an open question.
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.
| Property | Value | Notes |
|---|---|---|
| Common route | Intranasal | Also injected in some animal work |
| Solubility class | Freely soluble in water | Solid form is hygroscopic |
| Typical storage | About -20 degrees Celsius | Keep desiccated and dark |
| Purity method | Reverse-phase HPLC | Reported as area percent |
| Confirmatory method | Mass spectrometry | Verifies expected molecular mass |
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.
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.
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.
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, 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.
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.
In most people with Alport syndrome (about 85%), the condition is inherited in an X-linked pattern, due to mutations in the COL4A5 gene. A condition is considered X-linked if the gene involved in the disorder is located on the X chromosome. In males, who have only one X chromosome, one altered copy of the COL4A5 gene is sufficient to cause severe Alport syndrome, explaining why most affected males eventually develop kidney failure. In females, who have two X chromosomes, a mutation in one copy of the COL4A5 gene usually results in blood in the urine, but most affected females do not develop kidney failure. Alport syndrome can also be inherited in an autosomal recessive pattern if both copies of the COL4A3 or COL4A4 gene, located on chromosome 2, have been mutated. Most often, the parents of a child with an autosomal recessive disorder are not affected but are carriers of one copy of the altered gene. Past descriptions of an autosomal dominant form are now usually categorized as other conditions. Notably, conditions associated with giant platelets and associated with mutations of MYH9 are no longer considered to be Alport variants. However apparent autosomal dominant transmission of disease associated with mutations in COL4A3 and COL4A4 does occur. Clinical utility gene card for: Alport syndrome.
=== Therapeutic targeting in autoimmune disease === Therapies seek to disrupt the IgG-FcRn interaction to increase the clearance of disease-causing IgG autoantibodies from the body. One such therapy is the infusion of intravenous immunoglobulin (IVIg) to saturate FcRn's IgG recycling capacity and proportionately reduce the levels of disease-causing IgG autoantibody binding to FcRn, thereby increasing disease-causing IgG autoantibody removal. More recent approaches involve the strategy of blocking the binding of IgG to FcRn by delivering antibodies that bind with high affinity to this receptor through their Fc region or variable regions. These engineered Fc fragments or antibodies are being used in clinical trials as treatments for antibody-mediated autoimmune diseases such as primary immune thrombocytopenia and skin blistering diseases (pemphigus), and the Fc-based inhibitor, efgartigimod, based on the 'Abdeg' technology was recently approved (as 'Vyvgart') for the treatment of generalized myasthenia gravis in December 2021.
Israel: GBL was classified as a proscribed substance from 2007. Netherlands: GBL is unlike GHB not listed in the narcotics law, but its distribution is controlled. Possession is not illegal but may be punished according to the Medicines Act, when intended to be sold for human consumption or synthesis of GHB. People's Republic of China: GBL was regulated as a Class III drug precursor since 7 June 2021. Poland: GBL is classified as a drug. A license is mandatory for the manufacture, processing, reworking, importing, distribution of GBL. Russia: GBL has been classified as a psychotropic substance since 22 February 2012. Its trafficking is limited, and non-licensed selling, buying or any other use is punishable by imprisonment up to 20 years. Sweden: GBL is not classified as a drug but as a health-endangering substance. Although recently passed legislation to enter into force on 1 April 2011 will make it possible to handle narcotics for industrial purposes will enable GBL and 1,4-Butanediol to be classified as controlled substances. United Kingdom: Because of their legitimate uses, regulation 4B of the 2001 regulations makes it lawful to import, export, produce, supply, offer to supply or possess GBL and 1,4-BD, except where a person does so knowing or believing that they will be used for the purpose of human ingestion. Otherwise it is a class B controlled substance. United States: GBL is regulated as a List I controlled chemical. As a GHB analog, it is also treated as a controlled substance under Schedule I of the Controlled Substances Act if intended for human consumption.
Sources: en.wikipedia.org
== Prediction == Because viscosity depends continuously on temperature and pressure, it cannot be fully characterized by a finite number of experimental measurements. Predictive formulas become necessary if experimental values are not available at the temperatures and pressures of interest. This capability is important for thermophysical simulations, in which the temperature and pressure of a fluid can vary continuously with space and time. A similar situation is encountered for mixtures of pure fluids, where the viscosity depends continuously on the concentration ratios of the constituent fluids For the simplest fluids, such as dilute monatomic gases and their mixtures, ab initio quantum mechanical computations can accurately predict viscosity in terms of fundamental atomic constants, i.e., without reference to existing viscosity measurements. For the special case of dilute helium, uncertainties in the ab initio calculated viscosity are two order of magnitudes smaller than uncertainties in experimental values. For slightly more complex fluids and mixtures at moderate densities (i.e. sub-critical densities) Revised Enskog Theory can be used to predict viscosities with some accuracy. Revised Enskog Theory is predictive in the sense that predictions for viscosity can be obtained using parameters fitted to other, pure-fluid thermodynamic properties or transport properties, thus requiring no a priori experimental viscosity measurements. For most fluids, high-accuracy, first-principles computations are not feasible.
Mindlin (1928), engineer, Medal for Merit and ASME Medal recipient Harold Charles Bold (1929), botanist Jule Eisenbud (1929), psychiatrist known for research into parapsychology Theodore Lidz (1930), Sterling Professor of psychiatry at Yale; expert on schizophrenia Judd Marmor (1930), psychoanalyst and psychiatrist on homosexuality Herbert L. Anderson (1931), director of the Enrico Fermi Institute, professor of the University of Chicago Paul E. Queneau (1931), professor of metallurgical engineering at Dartmouth College Bernard Glueck Jr. (1933), psychiatrist, former president of the American Psychopathological Association Irving Kaplan (1933), chemist, professor at Massachusetts Institute of Technology Leo Rangell (1933), psychoanalyst; president of the International Psychoanalytical Association and the American Psychoanalytic Association John K. Lattimer (1935), urologist, ballistics expert, and inveterate collector Emanuel Papper (1935), anesthesiologist, dean of the Miller School of Medicine at the University of Miami 1969–1981 Norman Foster Ramsey Jr. (1935), winner of the Nobel Prize in Physics Robert Marshak (1936), president of the American Physical Society and president of the City College of New York Julian Schwinger (1936), winner of the Nobel Prize in Physics; posited the Schwinger effect Barry Commoner (1937), leading environmentalist, former editor of Science Illustrated magazine Francis J. Ryan (1937), professor of zoology at Columbia University Boris Jacobsohn (1938), professor of Physics at the University of Washington David B.
== Jung's wound == Scholars suggest that Jung's childhood vulnerabilities compelled him to heal his own life. Jung stated that "certain psychic disturbances can be extremely infectious if the doctor himself has a latent predisposition in that direction...For this reason he runs a risk - and must run it in the nature of things". Further he stated that "it is no loss, either, if [the analyst] feels that the patient is hitting him, or even scoring off him: it is his own hurt that gives the measure of his power to heal". Jungians acknowledge that Jung's own wounds could cause damage to those he was attempting to heal.
=== Secondhand cannabis smoke === A 2022 study found that smoking cannabis using a bong can greatly increase background levels of fine particulate matter, a carcinogen, in an enclosed space such as a living room. After 15 minutes, mean levels of particulate matter were more than twice the Environmental Protection Agency hazardous air quality threshold, and after 140 minutes, the concentrations were four times greater than those generated by smoking tobacco using a cigarette or hookah. This suggests secondhand cannabis smoke from bongs may present a health risk to non-smokers.
Sources: en.wikipedia.org
Most published work uses intranasal application, either as drops or as a nasal spray. Injection routes appear in a smaller set of animal experiments. Oral use is uncommon in the literature because peptide breakdown and poor absorption limit this route.
Reported human trials are few, brief and originate mainly from one country. They describe effects on anxiety-related measures, but sample sizes are small and reporting is limited. The results are widely regarded as preliminary rather than confirmed.
Reverse-phase liquid chromatography is used to assess purity and separation of related impurities. Mass spectrometry confirms that the observed molecular mass matches the expected peptide. A certificate of analysis from the supplier is the usual document of record.
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.