Selank 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 2026-08-01. Numbers and descriptions here follow the published literature rather than marketing material.
Reported pharmacological effects center on reduced anxiety-like behavior in animal models and on measures of memory and learning. Proposed contributing mechanisms include modulation of GABAergic signaling, shifts in monoamine turnover, and changes in the activity of enzymes that degrade neuropeptides. Effects on the expression of genes linked to neuroplasticity have also been described. No single molecular target is widely accepted, and whether the behavioral findings arise from one pathway or several remains an open question.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed as a stabilized analogue of tuftsin, a naturally occurring tetrapeptide fragment derived from the immunoglobulin heavy chain. The additional Pro-Gly-Pro segment at the carboxyl terminus is intended to slow enzymatic cleavage. The compound is usually described in the literature as a synthetic peptide with anxiolytic and cognitive-related activity, a label that reflects a research context rather than an approved therapeutic category.
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.
Proposed mechanisms center on modulation of the GABA system, but no single molecular target has been confirmed. Rodent studies report changes in GABA-A receptor expression and in the turnover of serotonin, dopamine, and norepinephrine in several brain regions. Increases in brain-derived neurotrophic factor and its receptor have also been described after repeated administration. These findings come largely from animal models, and the degree to which they describe human neurochemistry remains an open question. The mechanism is best characterized as multi-system and not fully resolved.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C33H57N11O9 | Derived from the seven-residue sequence |
| Molecular weight | About 751.9 g/mol | Average mass; the monoisotopic value is slightly lower |
| Residue count | Seven amino acids | Thr-Lys-Pro-Arg-Pro-Gly-Pro |
| Parent compound | Tuftsin (Thr-Lys-Pro-Arg) | Selank extends tuftsin at the C-terminus |
| Compound class | Synthetic short peptide | Studied in a research setting; not a licensed drug in most markets |
Dry powder is normally held at -20 degrees Celsius or lower, in a sealed container with desiccant and protection from light. Reconstituted solutions are usually kept at 2 to 8 degrees Celsius for short periods and frozen for longer ones. Proline residues at several positions are generally associated with some resistance to peptidase attack, but chemical stability still declines at neutral to alkaline pH and at elevated temperature. Exact shelf-life figures are product-specific and are not standardised across suppliers.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, with mass spectrometry used to confirm molecular mass and sequence information. Amino acid analysis and peptide mapping may supplement these methods. Certified reference standards are scarce, and many commercial lots are sold as research chemicals without a pharmacopoeial monograph. Regulatory treatment differs by country: Selank is a registered prescription medicine in Russia, while in the European Union and the United States it is not an approved drug and may fall under research-chemical or unapproved-product frameworks.
Selank is a hydrophilic peptide and dissolves readily in water and in aqueous buffers. The lyophilised powder is typically a white to off-white solid. Because short peptides are prone to hydrolysis and oxidation, handling benefits from limiting exposure to heat, moisture and strong light. Working solutions are commonly prepared in sterile water or saline, and repeated freeze-thaw cycles are avoided to reduce aggregation and loss of activity. These practices reflect general laboratory convention rather than published stability specifications.
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.
Characterization of Selank in a laboratory setting relies on standard peptide methods. Reverse-phase high-performance liquid chromatography separates the target from related impurities and provides a purity figure, commonly reported as 95 percent or higher. Mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, confirms the molecular mass and helps detect truncation or modification. Amino acid analysis can verify composition when a sequence-level check is needed. These techniques together establish identity and purity for a given lot.
Lyophilized Selank, the dry powder form, is generally stored frozen at minus 20 degrees Celsius or colder for long-term keeping. The solid is hygroscopic and should stay sealed, dry, and protected from light. Once dissolved, the peptide is less stable and is usually held refrigerated at 2 to 8 degrees Celsius for short periods. Repeated freezing and thawing is avoided because it can promote aggregation and loss of activity. Buffers and pH choice also affect how long a solution remains usable.
Solubility behavior is a practical concern for handling. Selank dissolves readily in water and in common aqueous buffers, which simplifies preparation of working solutions. The choice of solvent, ionic strength, and pH can influence aggregation over time, particularly at higher concentrations. Aqueous solutions are typically sterile-filtered before use. Because stability depends on several variables, storage and handling notes should be treated as general guidance rather than fixed rules, and specific values are best confirmed against a certificate of analysis for each batch.
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.
Naming conventions place Selank in the same research family as Semax, another Russian-developed peptide investigated for cognitive effects. The two compounds share a lineage but differ in sequence and in the biological systems proposed as their targets. Semax descends from ACTH fragments, whereas Selank descends from tuftsin. Publications sometimes identify Selank by its full peptide sequence or by laboratory codes rather than one uniform trade name. Because replication outside Russia is limited, reports on its properties are best read alongside the study design and the purity of the material tested.
=== As an allergen === Whether hydrolyzed vegetable protein is an allergen or not is contentious. According to European law, wheat and soy are subject to allergen labelling in terms of Regulation (EU) 1169/2011 on food information to consumers. Since wheat and soy used for the production of HVP are not exempted from allergen labelling for formal reasons, HVP produced by using those raw materials has to be labelled with a reference to wheat or soy in the list of ingredients. Nevertheless, strong evidence indicates at least aHVP is not allergenic, since proteins are degraded to single amino acids which are not likely to trigger an allergic reaction. A 2010 study has shown that aHVP does not contain detectable traces of proteins or IgE-reactive peptides. This provides strong evidence that aHVP is very unlikely to trigger an allergic reaction to people who are intolerant or allergic to soy or wheat. Earlier peer-reviewed animal studies done in 2006 also indicate that soy-hypersensitive dogs do not react to soy hydrolysate, a proposed protein source for soy-sensitive dogs. There are reports of a cosmetic-grade aHVP, Glupearl 19S (GP19S), inducing anaphylaxis when present in soap. Unlike food aHVP, this Japanese wheat aHVP is only very mildly hydrolyzed. The unusual chemical condition makes GP19S more allergenic than pure gluten. Newer regulations for cosmetic hydrolyzed wheat protein have been developed in response, requiring an average molecular mass of less than 3500 Da – about 35 residues long.
=== Women === Hyperandrogenism, especially high levels of testosterone, can cause serious adverse effects if left untreated. High testosterone levels are associated with other health conditions such as obesity, hypertension, amenorrhea (cessation of menstrual cycles), and ovulatory dysfunction, which can lead to infertility. Prominent signs of hyperandrogenism are hirsutism (unwanted growth of hair, especially in the abdominal region and on the back), adult acne, deepening of the voice, and alopecia (balding). Hyperandrogenism has also been observed to increase insulin tolerance, which can lead to type two diabetes and dyslipidemia, such as high cholesterol. These effects may have psychological impacts, sometimes leading to social anxiety and depression, especially in adolescent girls and young women. Paired with obesity and hirsutism, it can cause the individual to have low self-esteem.
Histoire et dictionnaire de Paris [History and dictionary of Paris] (in French). Paris: Éditions Robert-Laffont. Auguste, Jal (1872). Dictionnaire critique de biographie et d'histoire [Critical Dictionary of Biography and History] (in French). Paris: Éditions Plon. Piot, Eugène (1873). État civil de quelques artistes français [Marital status of some French artists] (in French). Paris: Librairie Pagnerre.
The enzyme α-carbonic anhydrase (CA) plays a vital role in regulating inorganic carbon balance within coral cells. It catalyzes two reversible reactions: the hydration of carbon dioxide (CO2) into bicarbonate (HCO−3) and a proton (H+), and the dehydration of bicarbonate back into CO2 and a proton. Through these interconversions, α-carbonic anhydrase facilitates the efficient transport and supply of dissolved inorganic carbon for both photosynthesis and calcification, maintaining the delicate equilibrium between CO2 and bicarbonate required for coral metabolic and skeletal processes. Ocean acidification poses a major threat to coral calcification by reducing the availability of carbonate ions (CO2−3), which are essential for forming calcium carbonate (CaCO3) skeletons. Under increasingly acidified conditions, corals must expend more energy to pump protons (H+) out of the calcifying space in order to maintain favorable conditions for mineral deposition. This heightened energetic demand compromises coral growth and skeletal density, resulting in weaker and more brittle structures. Consequently, coral reefs become more susceptible to physical damage from waves and storms, as well as less resilient to other environmental stressors.
Kopi luwak is one of the most expensive coffees in the world, selling for between $220 and $1,100 per kilogram ($100 and $500/lb) in 2010. The price paid to collectors in the Philippines is closer to US$20 per kilogram. The specialty Vietnamese weasel coffee, which is made by collecting coffee beans eaten by wild civets, is sold at US$500 per kilogram. Most customers are Asian, especially those originating from Japan, China, and South Korea. Some specialty coffee shops sell cups of brewed kopi luwak for US$35–80.
Sources: en.wikipedia.org
== Clinical significance == Its presence is associated with cardiovascular and kidney diseases. Like other S100 proteins, S100A12 signals through the RAGE receptor and TLR. In general, this signalling leads to cytokine production, chemotaxis and increased oxidative stress. In endothelial cells, this signaling leads to activation of NFκB, under which the production of adhesion molecules such as ICAMs, VCAM or selectins is increased. This protein is proposed to be involved in specific calcium-dependent signal transduction pathways and its regulatory effect on cytoskeletal components may modulate various neutrophil activities. Cascades that are triggered by interaction of S100A12 with RAGE may play an important role in renal failure in hemodialysis patients. The relationship between S100A12 and renal dialysis mortality rates has been repeatedly reported. S100A12 may play a role in monitoring SLE patients as a marker of kidney damage in glomerulonephritis. It is also associated with gastrointestinal diseases. In inflammatory bowel diseases, it significantly correlates with disease activity and, together with other 100S family proteins, can predict disease relapse.
Muscle cells work by detecting a flow of electrical impulses from the brain which signals them to contract through the release of calcium by the sarcoplasmic reticulum. Fatigue (reduced ability to generate force) may occur due to the nerve, or within the muscle cells themselves.
=== United States === The approach in the United States to stop money laundering is usually broken into two areas: preventive (regulatory) measures, and prosecutorial measures. In the United States, whistleblowers can report money laundering activities to the Financial Crimes Enforcement Network (FinCEN) or the Securities and Exchange Commission (SEC) if the case also implicates a security.
Kidder had mental health issues from a young age, which stemmed from undiagnosed bipolar disorder. "I knew I was different, had these mind flights that other people didn't seem to have," she recalled. At age 14, she attempted suicide. Kidder found an outlet in acting, as she felt she could "let my real self out ... and no one would know it was me." "Nobody ever encouraged me to be an actress," she recalled. "It was taken as a joke... As a teenager, I envisioned myself in every book I read. I wanted to be Henry Miller and Thomas Wolfe. I wanted to eat everything on the world's platter, but my eyes were bigger than my stomach." She attended several schools during her youth as a result of her family's relocations, eventually graduating from Havergal College, a high-school-level boarding school in Toronto, in 1966. In 1966, she found herself pregnant by her boyfriend, who arranged for an illegal abortion. The abortionist was located in a hotel room and filled Kidder's uterus with Lysol to terminate the pregnancy. After graduating from Havergal, Kidder relocated to Vancouver to attend the University of British Columbia, but dropped out after one year. She returned to Toronto, where she found work as a model.
Sources: en.wikipedia.org
These nuclides are listed in order of decreasing stability. Many of them are so nearly stable that they compete for abundance with stable isotopes of their respective elements; in fact, for three elements (indium, tellurium, and rhenium) a very long-lived radioactive primordial nuclide is more abundant than a stable nuclide. The longest-lived radionuclide known, 128Te, has a half-life of 7.5×1024 years: this is 5.5×1014 times the age of the Universe. Only four of these 35 nuclides have half-lives shorter than, or nearly equal to, the age of the universe. Most of the other 30 have half-lives much longer. The shortest-lived primordial, 235U, has a half-life of 704 million years, about 15% of the age of the Earth and Solar System. Many of these nuclides decay by double beta decay, although some like 209Bi decay by other means like alpha decay.
== Indications == It is a highly selective dipeptidyl peptidase-4 inhibitor that is typically used as an add on treatment when the first line treatment of metformin is not achieving the expected glycemic goals; though it has been approved for use as a first line treatment when metformin cannot be used.
The discovery was made throughout a series of experiments in the 1960s that discovered that reduced and denatured RNase in its unfolded form could refold into the native tertiary form. The tertiary structure of a protein is a fully folded polypeptide chain with all hydrophobic R-groups folded into the interior of the protein to maximize entropy with interactions between secondary structures such as beta sheets and alpha helixes. Since the structure of proteins determines its function, it is critical that a protein be folded correctly into its tertiary form so that the protein will function properly. However, it is important to note that polypeptide chains may differ vastly in primary structure, but be very similar in tertiary structure and protein function.
Sources: en.wikipedia.org
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, designed as a metabolically stabilized analogue of the endogenous tetrapeptide tuftsin. It has been studied mainly against anxiety-related and cognitive endpoints rather than as an approved medicine in most jurisdictions.
Tuftsin contains four residues, while selank carries an additional Pro-Gly-Pro segment at the carboxyl end. That extension is intended to reduce enzymatic cleavage. Comparative pharmacokinetic data in humans remain limited.
No single receptor target is widely accepted as the definitive mediator of the reported effects. Proposed contributors include GABAergic modulation, shifts in monoamine turnover, and altered neuropeptide degradation. The mechanism is treated in the literature as unresolved.
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.