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.
Last reviewed on 2025-12-29. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Selank is not a naturally occurring peptide and has no known endogenous counterpart in human physiology. Russian-language sources frequently call it TP-7, while English-language sources use the name Selank almost exclusively. Database indexing is uneven, partly because early reports appeared in regional journals that are not widely cataloged. Some summaries describe the material as a tuftsin analog and others as a synthetic heptapeptide; the labels overlap rather than conflict. Citing the primary sequence resolves ambiguity more reliably than the research or trade name alone.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter notation. Its structure consists of the immunomodulatory tetrapeptide tuftsin, Thr-Lys-Pro-Arg, extended at the carboxyl terminus by a Pro-Gly-Pro segment. The molecular formula is commonly given as C33H57N11O9, corresponding to a monoisotopic mass near 751.4 Da and an average molecular mass near 751.9 Da. All seven residues are proteinogenic amino acids, and the molecule carries no modified side chains or non-natural linkages.
| 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 |
Lyophilised material kept dry at minus 20 degrees Celsius or colder is the most stable form, and suppliers commonly state a shelf life of two years or more under those conditions. Once dissolved, degradation accelerates through hydrolysis and deamidation, particularly at alkaline pH or elevated temperature. Working solutions are usually divided into single-use aliquots to avoid repeated freeze-thaw cycles. The choice of reconstitution solvent affects both stability and the ionic strength of the final preparation.
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.
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.
Identity and purity of selank are established with reversed-phase high-performance liquid chromatography coupled to mass spectrometry. The peptide elutes from C18 columns with acetonitrile gradients in water containing trifluoroacetic acid or formic acid, and detection is usually performed by ultraviolet absorbance near 214 nm. Electrospray ionization in positive mode gives a doubly protonated ion near m/z 377, consistent with a mass of about 752 Da. Amino acid analysis or tandem mass spectrometry of fragment ions confirms the sequence. Because the molecule has no aromatic residues, it lacks a usable 280 nm chromophore, so low-wavelength detection or mass spectrometry is required.
Peptide bonds in selank are susceptible to hydrolysis under strongly acidic or basic conditions, and the terminal proline residues are vulnerable to exopeptidase activity in biological samples. Lyophilized powder stored dry at -20 °C typically remains stable for extended periods, whereas aqueous solutions degrade faster and may lose measurable purity within days to weeks depending on pH, temperature, and microbial load. Repeated freeze-thaw cycles promote aggregation and adsorption to container surfaces. For analytical work, solutions are usually prepared fresh, kept cold, and used within a single working day.
Handling follows standard practice for research peptides. Material is weighed in a low-humidity environment because the powder absorbs atmospheric moisture. Purity is reported as the percentage area of the main peak in a chromatogram, with specifications commonly set at 95 percent or higher; values below that threshold indicate the presence of truncated or modified species. Residual trifluoroacetate from purification is often present and may affect mass balance. Certificates of analysis should state the analytical method, the column and gradient used, and the lot-specific retention time so that results can be compared across suppliers.
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.
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.
HBTU activates carboxylic acids by forming a stabilized HOBt (Hydroxybenzotriazole) leaving group. The activated intermediate species attacked by the amine during aminolysis is the HOBt ester. To create the HOBt ester, the carboxyl group of the acid attacks the imide carbonyl carbon of HBTU. Subsequently, the displaced anionic benzotriazole N-oxide attacks of the acid carbonyl, giving the tetramethyl urea byproduct and the activated ester. Aminolysis displaces the benzotriazole N-oxide to form the desired amide.
== Artificial cartilage == Synthetic cartilage can be composed of many different materials that mimic its functional properties. Tissue engineering principles include the use of cells, growth factors, and synthetic scaffolds in order to do this.
The word is derived from the Ancient Greek χηλή, chele, meaning "crab pincers", and the suffix -oid, meaning "like". In the 19th century it was known as the "Keloid of Alibert" as opposed to "Addison's keloid" (Morphea). The famous American Civil War-era photograph "Whipped Peter" depicts an escaped former slave with extensive keloid scarring as a result of numerous brutal beatings from his former overseer. Intralesional corticosteroid injections were introduced as a treatment in the mid-1960s as a method to attenuate scarring. Pressure therapy has been used for the prophylaxis and treatment of keloids since the 1970s. Topical silicone gel sheeting was introduced as a treatment in the early 1980s.
Lutetium (177Lu), which decays with the emission of a low-energy electron, is useful for treating some cancerous tumors. Several compounds of 177Lu are available for this purpose: 1) Lutetium chloride, LuCl3, sold under the brand name Lumark among others, is used for radiolabeling other medicines, either as an anti-cancer therapy or for scintigraphy (medical radio-imaging). Its most common side effects are anaemia (low red blood cell counts), thrombocytopenia (low blood platelet counts), leucopenia (low white blood cell counts), lymphopenia (low levels of lymphocytes, a particular type of white blood cell), nausea (feeling sick), vomiting and mild and temporary hair loss. 2) Lutetium (177Lu) oxodotreotide, also known as Lutetium (177Lu) dotatate ("Lutathera"), has been approved for some types of tumors. 3) Lutetium (177Lu) vipivotide tetraxetan ("Pluvicto") has also been approved.
== Reactions == As a lactone, GBL is hydrolyzed under basic conditions, for example in a sodium hydroxide solution into sodium gamma-hydroxybutyrate, the sodium salt of gamma-hydroxybutyric acid. In acidic water, a mixture of the lactone and acid forms exists in an equilibrium. These compounds then may go on to form the polymer poly(4-hydroxybutyrate) as well as the dimer 1,6-Dioxecane-2,7-dione. When treated with a non-nucleophilic base, such as lithium diisopropylamide, GBL undergoes deprotonation of the alpha carbon atom to the carbonyl.
Sources: en.wikipedia.org
On 18 January, ambassadors from all 27 member states of the EU held an emergency meeting on Trump's threats. After Trump reversed his decision on implementing tariffs, EU officials were sceptical, but announced on 22 January that approval of the trade agreement would resume.
===== Alternative ===== TH2 cells play an important role in alternative macrophage activation as part of type 2 immune response against large extracellular pathogens like helminths. TH2 cells secrete IL-4 and IL-13, which activate macrophages to become M2 macrophages, also known as alternatively activated macrophages. M2 macrophages express arginase-1, an enzyme that converts arginine to ornithine and urea. Ornithine help increase smooth muscle contraction to expel the worm and also participates in tissue and wound repair. Ornithine can be further metabolized to proline, which is essential for synthesizing collagen. M2 macrophages can also decrease inflammation by producing IL-1 receptor antagonist (IL-1RA) and IL-1 receptors that do not lead to downstream inflammatory signaling (IL-1RII).
=== Inland taipan === The inland taipan (Oxyuranus microlepidotus) is considered the most venomous snake in the world with a murine LD50 value of 0.025 mg/kg SC. Ernst and Zug et al. 1996 list a value of 0.01 mg/kg SC, which makes it the most venomous snake in the world in their study too. They have an average venom yield of 44 mg. Bites from this species have a mortality rate of 80% if left untreated, although it is very rare for this species to bite. This species is known to be a very shy, reclusive and a laid-back snake that will nearly always slither away from disturbance. It is not an aggressive species and rarely strikes. No recorded incidents have been fatal since the advent of the monovalent (specific) antivenom therapy.
Before the British prime minister left Rhodesia on 30 October 1965, he proposed a Royal Commission to gauge public opinion in the colony regarding independence under the 1961 constitution, possibly chaired by the Rhodesian Chief Justice Sir Hugh Beadle, which would report its findings to both the British and Rhodesian Cabinets. Wilson confirmed in the House of Commons two days later that he intended to introduce direct British control over the Rhodesian parliamentary structure to ensure that progress was made towards majority rule. Stalemate drew closer as the Rhodesian Cabinet resolved that since Wilson had ruled out maintenance of the status quo, its only remaining options were to trust in the Royal Commission or declare independence. When the terms for the commission's visit were presented to Smith, he found that contrary to what had been discussed during the British prime minister's visit, the Royal Commission would operate on the basis that the 1961 constitution was unacceptable to the British government, and that Britain would not commit itself to accepting the final report. Smith said these conditions amounted to a "vote of no confidence in [the commission] before they commenced", and therefore rejected them. "The impression you left with us of a determined effort to resolve our constitutional problem has been utterly dissipated", he wrote to Wilson on 5 November.
Sources: en.wikipedia.org
== Treatment == There is no distinct treatment option that can undo the effects and damage from rhabdomyolysis because it is a type of necrosis, where the tissue and body cells die prematurely. However, the rate of the pathology that can lead to more complications can be decreased by acting early and consistently. Overall treatment depends on preventing kidney failure (renal failure) which is done by rehydrating the patient. It also depends on making urine have a more basic pH (alkalinization of urine).
Caroxazone (Surodil, Timostenil) is an antidepressant which was formerly used for the treatment of depression but is now no longer marketed. It acts as a reversible monoamine oxidase inhibitor (RIMA) of both MAO-A and MAO-B subtypes, with five-fold preference for the latter.
Research suggests that during reproduction, fungal spores from X. parietina may engage in a form of reproductive parasitism (a type of symbiosis where a microorganism alters the reproduction of a host) by "stealing" algal partners from Physcia lichens, which contain the same algal species. This algal sharing strategy provides a reproductive advantage, as germinating X. parietina fungal spores can bypass the uncertain process of finding compatible free-living algae. However, the species engages in a long-term ecological succession pattern. Studies tracking lichen communities over five-year periods found that Physcia species (such as P. adscendens and P. caesia) are comparatively short-lived, typically developing and vanishing within about two years, while X. parietina populations persisted throughout. Eventually, in sheltered or humid locations, bryophytes (particularly Orthotrichum species) tend to invade and overgrow lichen-covered surfaces—representing the normal succession pattern in canopy situations. The regenerative capacity of X. parietina allows it to maintain its presence longer than many other lichen species during this successional process, but it is eventually replaced by vigorously growing mosses in most sheltered habitats.
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.
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter code. It combines the tetrapeptide tuftsin with a carboxyl-terminal Pro-Gly-Pro extension. This full sequence identifies the molecule more precisely than the research name.