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 2025-11-30. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
The compound was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences during the 1980s and 1990s. The stated design goal was to retain the immunomodulatory and central nervous system activity attributed to tuftsin while improving resistance to enzymatic breakdown. Adding a proline-rich tail to the short parent peptide was a deliberate strategy, because proline residues restrict the conformations available to many peptidases. The same laboratory produced Semax, an ACTH fragment analog, and both compounds were developed in parallel as short, enzymatically stabilized peptides intended for intranasal use.
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 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.
| Property | Value | Notes |
|---|---|---|
| Peptide sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Seven residues; tuftsin plus a Pro-Gly-Pro tail |
| Molecular formula | C33H57N11O9 | Commonly reported value for the free peptide |
| Monoisotopic mass | Roughly 751.4 Da | Average molecular mass near 751.9 Da |
| Appearance | White to off-white powder | Typically supplied as a lyophilized solid |
| Solubility class | Freely soluble in water | Also dissolves in saline and other polar solvents |
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.
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.
Published clinical work is concentrated in Russian-language journals and generally involves small samples without independent replication. Systematic reviews in English note the shortage of randomised, placebo-controlled trials and the difficulty of verifying methods from translated reports. Outcome measures vary between studies, which complicates pooling of results. Interest in the compound as a cognitive or anxiolytic agent therefore rests on a thinner evidence base than the volume of citations suggests. Replication in well-powered trials with preregistered endpoints would be needed before firm conclusions about efficacy can be drawn.
Proposed mechanisms centre on the GABAergic system. Animal and tissue studies report changes in GABA-A receptor expression and reduced activity of GABA transaminase, the enzyme that degrades GABA. Effects on monoamine turnover, including serotonin and dopamine pathways, are also described, and a separate line of work links the peptide to increased expression of brain-derived neurotrophic factor in hippocampal tissue. Most of these findings come from rodent models and cell preparations. How the individual observations combine into a single coherent mode of action is not settled.
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 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.
Most published work on selank originates from a small number of research groups in the Russian Federation. A large share of that record appears in Russian-language journals, which limits access for readers who rely on English-indexed databases. Independent replication by laboratories outside the original research network is sparse in publicly available sources. This concentration of origin and language is a frequently noted feature when the compound is summarized in broader reviews of synthetic peptides.
Anemia with a low MCHC is called hypochromic anemia. If anemia is present but the red blood cell indices are normal, the anemia is considered normochromic and normocytic. The term hyperchromia, referring to a high MCHC, is generally not used. Elevation of the MCHC above the upper reference value is rare, mainly occurring in conditions such as spherocytosis, sickle cell disease and hemoglobin C disease. An elevated MCHC can also be a false result from conditions like red blood cell agglutination (which causes a false decrease in the red blood cell count, elevating the MCHC) or highly elevated amounts of lipids in the blood (which causes a false increase in the hemoglobin result). Microcytic anemia is typically associated with iron deficiency, thalassemia, and anemia of chronic disease, while macrocytic anemia is associated with alcoholism, folate and B12 deficiency, use of some drugs, and some bone marrow diseases. Acute blood loss, hemolytic anemia, bone marrow disorders, and various chronic diseases can result in anemia with a normocytic blood picture. The MCV serves an additional purpose in laboratory quality control. It is relatively stable over time compared to other CBC parameters, so a large change in MCV may indicate that the sample was drawn from the wrong patient.
Geheimrat Julius Wilhelm Theodor Curtius (27 May 1857 – 8 February 1928) was professor of Chemistry at Heidelberg University. He published the Curtius rearrangement in 1890/1894 and also discovered diazoacetic acid, hydrazine and hydrazoic acid. In 1882 he carried out the first ever peptide synthesis, creating the N-protected dipeptide, benzoylglycylglycine.
== External links == Media related to Scutellaria at Wikimedia Commons Data related to Scutellaria at Wikispecies "Scutellaria L. (skullcap)". The PLANTS Database. United States Department of Agriculture. Scutellaria images. MorphBank.
=== The JGRB and the Representative Body for Sergeants and Inspectors === From 1927 to 1962, Garda members were represented for limited purposes by a Joint Garda Representative Body (JGRB); this body was criticised as dominated by senior officers and unable to secure needed changes in conditions of work. After a major and unauthorised meeting of hundreds of rank-and-file Gardaí at the Macushla Ballroom in Dublin, a chain of events led to the establishment by the then Minister for Justice, Charles Haughey, of three new representative bodies, divided by rank, including the Representative Body for Inspectors, Station Sergeants and Sergeants (RBISS). That body was permitted to appoint a sergeant, on secondment, as its part-time general secretary. It was also permitted to apply to the Garda Commissioner for permission to request a subscription from members. The three bodies could, and were required to if requested by the Garda Commissioner, form a temporary joint representative body. There was cooperation at other levels too, with the magazine The Garda Review being issued by the GRA and AGSI together.
10 May Transgender woman Lexi-Rose Crawford is sentenced to 9 years in prison for raping a female victim, with the sentence to be served in a men's prison. The government confirms it will replace its plan for all EU-era legislation to expire at the end of 2023 with a list of 600 laws it wishes to replace. Vodafone confirms it will begin switching off its 3G network from June, prompting concerns that people with older and more basic phones could experience "digital poverty". The legal case Duke of Sussex v Mirror Group Newspapers begins at the High Court. Adam Price announces his resignation as leader of Plaid Cymru after a report found a culture of misogyny, harassment and bullying in the party. 11 May Wind power is reported as the main source of electricity generation in the UK for the first three months of the year, overtaking gas. The government announces that TransPennine Express will be stripped of its contract and nationalised, due to poor service and cancelled trains. The Bank of England raises its baseline interest rate for the 12th consecutive time, from 4.25% to 4.5%, increasing mortgage and loan costs, but increasing savings income for many. Defence Secretary Ben Wallace confirms that the UK will supply Storm Shadow cruise missiles to Ukraine, to assist the country in repelling the Russian invasion. These have a much longer range (250 km/155 mi) than US-supplied HIMARS missiles (80 km/50 mi).
Sources: en.wikipedia.org
After the lipids are separated on the GC or LC column they are detected using mass spectrometry (MS). Mass spectrometry characterizes the mass of a given molecule by first fragmenting and ionizing the molecule into smaller carbocations known as daughter ions. Each molecule has a diagnostic fragmentation pattern in a given ion source. Classes of molecules often have a characteristic fragment ion that can be used to search for those molecules in a total ion current. This is known as a selected ion chromatogram (SIC). SICs are used in single quadrupole mass spectrometers. When two quadrupoles are attached in tandem mass spectrometry (MS/MS), two mass fragments can be isolated simultaneously. MS/MS experiments allow the total ion current to be filtered by both the molecular ion and the characteristic fragment ion of a given molecule. The molecular ion of gammacerane with an electron impact source is 412 m/z. Like other pentacyclic triterpenoids, it has a characteristic 191 m/z mass fragment. The combination of 412 m/z and 191 m/z is known as the 412-->191 m/z transition and can be used to search a chromatogram specifically for gammacerane.
RCH(NH2)CO2H ⇌ RCH(N+H3)CO−2 The ratio of the concentrations of the two species in solution is independent of pH. The zwitterionic form in the solid state is stabilized by hydrogen bonds. Zwitterions may also be present in the gas phase for some cases different from the simple carboxylic acid-to-amine transfer.
Psychedelic therapy (or psychedelic-assisted therapy) is the proposed use of psychedelic drugs to treat mental disorders. As of 2021, psychedelic drugs are controlled substances in most countries and psychedelic therapy is not legally available outside clinical trials. However, certain psychedelics like psilocybin and LSD are legally approved and/or used for treatment of conditions like treatment-resistant depression under special access programs in several countries including Australia, Switzerland, Canada, and Israel. The procedure for psychedelic therapy differs from that of therapies using conventional psychiatric medications. While conventional medications are usually taken without supervision at least once daily, in contemporary psychedelic therapy the drug is administered in a single session (or sometimes up to three sessions) in a therapeutic context. The therapeutic team prepares the patient for the experience beforehand and helps them integrate insights from the drug experience afterwards. After ingesting the drug, the patient normally wears eyeshades and listens to music to facilitate focus on the psychedelic experience, with the therapeutic team interrupting only to provide reassurance if adverse effects such as anxiety or disorientation arise. As of 2022, the body of high-quality evidence on psychedelic therapy remains relatively small and more, larger studies are needed to reliably show the effectiveness and safety of psychedelic therapy's various forms and applications.
=== Endocrine cells === There are many types of specialized endocrine cells that make up the larger tissues and glands of the endocrine system. The endocrine cells release hormones as molecular signals in endocrine signaling that target cells in more distant locations. In animals there are more than fifty such hormones released by the different endocrine glands. The pituitary gland, and the hypothalamus dominate most of the endocrine system. The pituitary gland is in two parts – the anterior pituitary, and the posterior pituitary. The posterior pituitary gland does not produce any hormone but stores and secretes hormones such as antidiuretic hormone (ADH) which is synthesized by supraoptic nucleus of hypothalamus and oxytocin which is synthesized by paraventricular nucleus of hypothalamus. ADH functions to help the body to retain water; this is important in maintaining a homeostatic balance between blood solutions and water. Oxytocin functions to induce uterine contractions, stimulate lactation, and allows for ejaculation. The pineal gland produces melatonin. The follicular cells of the thyroid gland produce and secrete the thyroid hormones T3 and T4 in response to elevated levels of TRH, produced by the hypothalamus, and subsequent elevated levels of TSH, produced by the anterior pituitary, which further regulates the metabolic activity and rate of all cells, including cell growth and tissue differentiation. The parathyroid glands produce and secrete parathyroid hormone in response to low calcium.
Sources: en.wikipedia.org
Ninhydrin (2,2-dihydroxyindane-1,3-dione) is an organic compound with the formula C6H4(CO)2C(OH)2. It is used to detect ammonia and amines. Upon reaction with these amines, ninhydrin gets converted into deep blue or purple derivatives, which are called Ruhemann's purple. Ninhydrin is most commonly used to detect fingerprints in forensic cases, as the terminal amines of lysine residues in peptides and proteins sloughed off in fingerprints react with ninhydrin. Ninhydrin is a white solid that is soluble in ethanol and acetone. Ninhydrin can be considered as the hydrate of indane-1,2,3-trione.
==== Aerosol mass spectrometer ==== The Aerodyne AMS provides real-time aerosol mass spectrometry analysis of size-resolved mass concentration of non-refractory components (Ex. organics, sulfate, nitrate, and ammonium). The term non-refractory is assigned to species that evaporate rapidly at 600 °C under vacuum conditions (e.g. organic matter, NH4NO3 and (NH4)2SO4. The schematic of a typical AMS is shown in the figure to the right. The Aerodyne AMS is made up of three sections; The aerosol inlet, the particle sizing chamber, and the particle detection chamber. The aerosol inlet has a flow limiting orifice entrance that is around 100 um in diameter. Once in the chamber the sample goes through aerodynamic focusing lens system, which consist of several orifice lenses that are mount in sequence of decreasing inner diameter. The lens focuses the particles into a narrow particle beam. The beam now travels through the particle sizing chamber, where the particle aerodynamic diameter is measured. The particle sizing chamber is made up of a flight tube maintained at (~ 10−5 torr). The entrance of the flight tube is a mechanical chopper that's used to modulate the particle beam; then using both the fixed length of the tube and the time-resolved detection of the arrival at the end, the particles' velocities can be determined. Using the velocity, the particle's diameter is obtained. As the particle beam exits the flight tube, it enters the particle composition detection chamber. In this section, the particles collide with a heated tungsten element (~600 °C).
FBGC's will also begin to produce reactive oxygen intermediates, enzymes for degradation, and acid between their cell membranes and the surface of the biomaterial. The composition of the biomaterial will determine how compatible and durable it is in the body. If too much damage occurs due to the chemicals that are produced, the biomaterial may fail and have to be replaced.
== Classification == There are over 100 peptides which have been claimed as falling within this group, though most of them have relatively little published research and only a dozen or so such compounds are widely known and well characterised. Most compounds referred to as matrikines are synthetic versions of peptide fragments 2-6 amino acids in length which are found in connective tissue proteins such as collagen, elastin, fibronectin and laminin, and were originally isolated as products of the enzymatic hydrolysis of these proteins. Many of these form naturally in the body following injury or tissue damage, and act as signalling factors which trigger tissue repair processes. Larger protein fragments cleaved from the full length connective tissue proteins, such as arresten, canstatin and tumstatin, also have similar functions and may be grouped along with the smaller peptide matrikines. There are also other peptide fragments which are commonly included in the matrikine group on the basis of their similar activity, despite not being derived from connective tissue proteins.
==== Parkinson's disease ==== Creatine's impact on mitochondrial function has led to research on its efficacy and safety for slowing Parkinson's disease. As of 2014, the evidence did not provide a reliable foundation for treatment decisions, due to risk of bias, small sample sizes, and the short duration of trials.
Sources: en.wikipedia.org
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.
No peptide with this exact sequence has been identified as an endogenous substance. It is a laboratory-designed analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The Pro-Gly-Pro extension has no known natural source.
Proline introduces conformational constraints that make a peptide less accessible to common peptidases. This is a standard stabilization strategy in peptide design. The added residues also increase the distance between the active tuftsin portion and typical cleavage sites.
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.