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.
Updated 2026-07-01. Numbers and descriptions here follow the published literature rather than marketing material.
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.
Measuring peptide exposure inside the brain is technically difficult. Selank is degraded rapidly in plasma, and assays must separate intact peptide from fragments, which favors targeted mass spectrometry over immunoassays alone. Reported half-lives are short, on the order of minutes, so effects observed hours later are attributed to downstream signaling rather than to the parent compound. Blood-brain barrier permeability is debated and rarely quantified directly. Gaps include absent dose-response characterization, inconsistent reporting of purity, and almost no pharmacokinetic data from human participants.
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.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. Its four N-terminal residues reproduce tuftsin, a tetrapeptide fragment of the immunoglobulin heavy chain, while the C-terminal Pro-Gly-Pro extension is a synthetic addition. The peptide has a molecular mass near 752 daltons and carries a net positive charge at physiological pH because of the arginine and lysine side chains. Published indexes list it under the name Selank and the sequence abbreviation TKPRPGP. Solid-phase peptide synthesis is the standard production route for research quantities.
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.
| 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 |
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.
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.
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.
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.
=== Age of onset === The definition of the onset of puberty may depend on perspective (e.g., hormonal versus physical) and purpose (establishing population normal standards, clinical care of early or late pubescent individuals, etc.). A common definition for the onset of puberty is physical changes to a person's body. These physical changes are the first visible signs of neural, hormonal, and gonadal function changes. The age at which puberty begins varies between individuals; usually, puberty begins between 10 and 13 years of age. The age at which puberty begins is affected by both genetic factors and by environmental factors such as nutritional state and social circumstances. An example of social circumstances is the Vandenbergh effect; a juvenile female mouse who has significant interaction with adult male mice will enter puberty earlier than juvenile females who are not socially overexposed to adult males. The average age at which puberty begins may be affected by ethnicity as well. For example, the average age of menarche in various populations surveyed has ranged from 12 to 18 years. The earliest average onset of puberty is for African-American females and the latest average onset for high altitude subsistence populations in Asia. However, much of the higher age averages reflect nutritional limitations more than genetic differences and can change within a few generations with a substantial change in diet.
== Kingdom of Holland (1806–1810) == In 1795, the Republic was overthrown by the French Republic and replaced with the Batavian Republic. In 1806 Napoleon abolished the new republic and made his brother King of Holland. However, in 1810 Napoleon invaded the Netherlands and annexed the country to the French Empire.
=== Rayon production === Reaction with ammonium hydroxide can yield tetraamminecopper(II) sulfate and Schweizer's reagent (nonsulphurous), which is used to dissolve cellulose in the industrial production of Rayon.
Sources: en.wikipedia.org
According to scholar Ray Jabre Mouawad, the Druze appreciated the two saints for their bravery, Saint George because he confronted the dragon and the Prophet Elijah because he competed with the pagan priests of Baal and won over them. In both cases the explanations provided by Christians are that Druzes were attracted to warrior saints that resemble their own militarized society. Saint George is considered the patron saint of Lebanese Christians, Palestinian Christians, Syrian Christians, and the Druze. Salman the Persian is honored as a prophet in the Druze faith, and as an incarnation of the monotheistic idea. As a practicing Zoroastrian, he dedicated much of his early life to studying to become a magus, though he later became preoccupied with travelling throughout Western Asia to engage in interfaith dialogue with other religious groups. His quests eventually prompted his conversion to Christianity and later his conversion to Islam, which occurred after he met and befriended Muhammad in the city of Yathrib. In 587 he met a Nestorian Christian group and was impressed by them. Against the wishes of his father, he left his family to join them. His family imprisoned him afterwards to prevent him but he escaped.
=== Regulations === The programs for safety regulation vary widely by the type of product, its potential risks, and the regulatory powers granted to the agency. For example, the FDA regulates almost every facet of prescription drugs, including testing, manufacturing, labeling, advertising, marketing, efficacy, and safety—yet FDA regulation of cosmetics focuses primarily on labeling and safety. The FDA regulates most products with a set of published standards enforced by a modest number of facility inspections. Inspection observations are documented on Form 483. In June 2018, the FDA released a statement regarding new guidelines to help food and drug manufacturers "implement protections against potential attacks on the U.S. food supply". One of the guidelines includes the Intentional Adulteration (IA) rule, which requires strategies and procedures by the food industry to reduce the risk of compromise in facilities and processes that are significantly vulnerable. The FDA also uses tactics of regulatory shaming, mainly through online publication of non-compliance, warning letters, and "shaming lists." Regulation by shaming harnesses firms' sensitivity to reputational damage. For example, in 2018, the agency published an online "black list", in which it named dozens of branded drug companies that are supposedly using unlawful or unethical means to attempt to impede competition from generic drug companies.
== Triquinoyl therapy == In the late 1940s, William J. Hale claimed that "triquinoyl", being a trimer of William Frederick Koch's glyoxylide, should be just as effective as the latter against "diabetes, arthritis, poliomyelitis, and even cancer". Even though there is no research supporting this claim (and Koch's glyoxylide preparations were found to be just distilled water), triquinoyl is still listed as an ingredient of some alternative medicine remedies.
== Cultural references == A 1990 Michael Winner film Bullseye!, starring Michael Caine and Roger Moore, referenced the Fleischmann and Pons experiment. The film – a comedy – concerned conmen trying to steal scientists' purported findings. However, the film had a poor reception, being described as "appallingly unfunny". In Undead Science, sociologist Bart Simon gives some examples of cold fusion in popular culture, saying that some scientists use cold fusion as a synonym for outrageous claims made with no supporting proof, and courses of ethics in science give it as an example of pathological science. It has appeared as a joke in Murphy Brown and The Simpsons. It was adopted as a software product name Adobe ColdFusion and a brand of protein bars (Cold Fusion Foods). It has also appeared in advertising as a synonym for impossible science, for example a 1995 advertisement for Pepsi Max. The plot of Chain Reaction, a 1996 action-adventure film, shows a theoretical variation of the cold fusion principle. The plot of The Saint, a 1997 action-adventure film, parallels the story of Fleischmann and Pons, although with a different ending. In Undead Science, Simon posits that film might have affected the public perception of cold fusion, pushing it further into the science fiction realm. In an episode of the Sci-fi television series Outer Limits that aired on June 26, 1998 an ex-student returns to his university with bombs he made by cracking the secret of cold fusion, after being expelled from the school's physics program.
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 seven-amino-acid peptide built from the tuftsin sequence plus a Pro-Gly-Pro tail. It is produced by chemical synthesis rather than extracted from a natural source. The free peptide is usually supplied as a lyophilised powder or in an aqueous formulation.