If you have been reading about peptide stability 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 2026-01-11. Numbers and descriptions here follow the published literature rather than marketing material.
Tuftsin, the parent structure, is a naturally occurring immunomodulatory tetrapeptide released from the Fc region of immunoglobulin G by spleen enzymes. Selank extends this four-residue sequence with three additional amino acids. The stated rationale is that the added tail slows enzymatic breakdown and may influence receptor interactions. How the full heptapeptide behaves at the molecular level is not firmly established, and proposed mechanisms often involve indirect modulation of neurotransmitter or immune signaling rather than a single defined target.
Selank is a synthetic heptapeptide developed in Russia. Its sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, a seven-residue chain built around the natural tetrapeptide tuftsin. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences first described the compound in the mid-1990s. The design combined the tuftsin core with an added Pro-Gly-Pro tail, a modification intended to extend the molecule's stability in biological fluids. Published work on the peptide has appeared mainly in Russian-language journals.
Reported activity for Selank centers on anxiolytic and nootropic effects. Russian clinical reports describe use in anxiety and in cognitive or attention-related complaints. Most of this evidence comes from studies conducted by the same research groups that developed the peptide. Independent replication in other countries remains limited, and no major Western regulatory agency has approved the compound for any indication. The gap between local reports and external verification is a recurring point in discussions of the peptide.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Modeled on tuftsin |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Seven residues |
| Approximate molecular mass | Around 750 Da | Depends on counter-ion and hydration |
| Common forms | Lyophilized powder | Also described as aqueous solution |
| Primary origin of research | Russian laboratories | Mid-1990s onward |
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.
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.
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.
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.
Pharmacokinetic data are sparse and largely derived from animal work. After intranasal administration the peptide appears in plasma within minutes, and reported half-lives are short, on the order of minutes to tens of minutes. Degradation proceeds through ordinary proteolytic cleavage into constituent amino acids and smaller fragments. Direct evidence that intact Selank reaches brain tissue in meaningful amounts is limited, and the extent of blood-brain barrier penetration is debated. Some authors argue that fragments, not the parent peptide, carry much of the observed activity.
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.
== External links == Clinical trial number NCT02229851 for "Trial to Compare the Efficacy and Safety of NNC0195-0092 (Somapacitan) With Placebo and Norditropin FlexPro (Somatropin) in Adults With Growth Hormone Deficiency. (REAL 1)" at ClinicalTrials.gov
According to US State Department Spokesperson, Jen Psaki : "US law exempts foreign government officials, including heads of state and heads of government from certain potential inadmissibility grounds". The visa refusal came after some Indian-American groups and human rights organizations with political view campaigned against Modi, including the Coalition Against Genocide. On June 11, 2014, Robert Blackwill, the former Coordinator for Strategic Planning and Deputy US National Security Advisor during the presidency of George W. Bush, spoke at length about India–U.S. relations and said : "Mr Modi is a determined leader. He is candid and frank. I also worked with him during the Gujarat earthquake when I was posted as (the US) ambassador to India. ... It was mistake by the current Obama administration to delay engagement with Mr Modi. I do not know why they did so but definitely, this did not help in building relationship. ... The old formula and stereotypes will not work if the US administration wants to engage with Mr Modi. The Indian prime minister is candid, direct and smart. He speaks his mind. The US administration also has to engage in candid conversation when Mr Modi meets President Obama later this year. They have to do something innovative to engage with him." Nicholas Burns, former U.S.
==== Bolsa Família ==== The Bolsa Família programme had been replaced by the previous government with the Auxílio Brasil. However, due to criticism of the latter, Bolsa Família was reimplemented by the Lula government, replacing Auxílio Brasil. The amount of R$600 reserved for the year 2022 in Auxílio Brasil was guaranteed by Bolsa Família, which would maintain it indefinitely, increasing its value to R$670; the new Bolsa Família started to be paid from March 2023. In July 2023, the federal government announced that more than 43.5 million people had left the poverty line in June, largely attributing the achievement to the reopening and reformulation of Bolsa Família, which now had the average payment of R$705,40 per family, the highest average in its history. Throughout 2023, the Cadastro Único (CadÚnico), the information base used to define families eligible for Bolsa Família, was revised and 1.7 million single-person families were excluded, according to the government, some members of families benefiting from Bolsa Família had separated themselves and formed, nominally, an independent family, in order to receive individual payment of the benefit, taking advantage of the declaratory feature of the registration.
uridine monophosphate (UMP)), usually to tyrosine propionylation pyroglutamate formation S-glutathionylation S-nitrosylation S-sulfenylation, reversible covalent addition of one oxygen atom to the thiol group of a cysteine residue to form a sulfenic acid S-sulfinylation, normally irreversible covalent addition of two oxygen atoms to the thiol group of a cysteine residue to form a sulfinic acid S-sulfonylation, normally irreversible covalent addition of three oxygen atoms to the thiol group of a cysteine residue, resulting in the formation of a cysteic acid residue sulfation, the addition of a sulfate group to a tyrosine.
Sources: en.wikipedia.org
The first two bus operating contracts for the new Weaver Network were awarded in September 2026 to FirstGroup, covering Huddersfield and parts of Leeds, and Transdev Blazefield, covering Dewsbury. In October 2021, £830 million of funding was announced for the West Yorkshire Combined Authority through the City Region Sustainable Transport Settlement, including funding to develop mass transit proposals for the region. Consultation was undertaken between July and September 2024 on proposed tram routes linking Bradford and Leeds, and St. James Hospital, central Leeds and White Rose Shopping Centre. Following a review by the National Infrastructure and Service Transformation Authority, the programme was moved to a more sequential approach intended to reduce delivery risk, contributing to a delay in the expected timetable for the scheme.
Protein DAMPs include intracellular proteins, such as heat-shock proteins or HMGB1, and materials derived from the extracellular matrix that are generated following tissue injury, such as hyaluronan fragments. Non-protein DAMPs include ATP, uric acid, heparin sulfate and DNA.
==== Body fluids ==== Cocaine and its major metabolites may be quantified in blood, plasma, or urine to monitor for use, confirm a diagnosis of poisoning, or assist in the forensic investigation of a traffic or other criminal violation or sudden death. Most commercial cocaine immunoassay screening tests cross-react appreciably with the major cocaine metabolites, but chromatographic techniques can easily distinguish and separately measure each of these substances. When interpreting the results of a test, it is important to consider the cocaine usage history of the individual, since a chronic user can develop tolerance to doses that would incapacitate a cocaine-naive individual, and the chronic user often has high baseline values of the metabolites in his system. Cautious interpretation of testing results may allow a distinction between passive or active usage, and between smoking versus other routes of administration.
=== Waste water treatment === Thanks to the easy separation by applying a magnetic field and the very large surface to volume ratio, magnetic nanoparticles have a potential for treatment of contaminated water. In this method, attachment of EDTA-like chelators to carbon coated metal nanomagnets results in a magnetic reagent for the rapid removal of heavy metals from solutions or contaminated water by three orders of magnitude to concentrations as low as micrograms per Litre. Magnetic nanobeads or nanoparticle clusters composed of FDA-approved oxide superparamagnetic nanoparticles (e.g. maghemite, magnetite) hold much potential for waste water treatment since they express excellent biocompatibility which concerning the environmental impacts of the material is an advantage compared to metallic nanoparticles.
In a meta-analysis of various trials involving fluoxetine (Prozac), fluvoxamine (Faverin/Luvox), and sertraline (Zoloft) to test their relative efficacies in treating OCD, clomipramine was found to be significantly more effective. Other studies have borne similar results even when risk of bias is eliminated. A potentially significantly greater inherent side-effect profile, however, makes it a second-line choice in the treatment of OCD. SSRIs are generally better-tolerated but appear to be inferior in terms of actual clinical efficacy.
Sources: en.wikipedia.org
=== Depression === Selegiline has been clinically studied in combination with oral L-phenylalanine or β-phenethylamine in the treatment of depression and was reported to be effective. L-Phenylalanine is known to be metabolized into β-phenethylamine, selegiline is known to strongly inhibit the metabolism of β-phenethylamine, and β-phenethylamine has been implicated in having psychostimulant-like mood-lifting effects.
The National Medical Products Administration is not responsible for regulating pharmaceutical ingredients manufactured and exported by chemical companies. This regulatory lack, which has resulted in considerable international news coverage unfavorable to China, has been known for a decade, but failure of Chinese regulatory agencies to cooperate has prevented improvement. In May 2005, the Chinese press agency Xinhua reported that the World Health Organization had established Rapid Alert System, the world's first web-based system for tracking the activities of drug counterfeiters, in light of the increasing severity of the problem of counterfeit drugs.
Most well-nourished people in industrialized countries have 4 to 5 grams of iron in their bodies (~38 mg iron/kg body weight for women and ~50 mg iron/kg body for men). Of this, about 2.5 g is contained in the hemoglobin needed to carry oxygen through the blood (around 0.5 mg of iron per mL of blood), and most of the rest (approximately 2 grams in adult men, and somewhat less in women of childbearing age) is contained in ferritin complexes that are present in all cells, but most common in bone marrow, liver, and spleen. The liver stores of ferritin are the primary physiologic source of reserve iron in the body. The reserves of iron in industrialized countries tend to be lower in children and women of child-bearing age than in men and in the elderly. Women who must use their stores to compensate for iron lost through menstruation, pregnancy or lactation have lower non-hemoglobin body stores, which may consist of 500 mg, or even less. Of the body's total iron content, about 400 mg is devoted to cellular proteins that use iron for important cellular processes like storing oxygen (myoglobin) or performing energy-producing redox reactions (cytochromes). A relatively small amount (3–4 mg) circulates through the plasma, bound to transferrin. Because of its toxicity, free soluble iron is kept in low concentration in the body. Iron deficiency first affects the storage of iron in the body, and depletion of these stores is thought to be relatively asymptomatic, although some vague and non-specific symptoms have been associated with it.
NASA achieved the first approach and landing test of its Space Shuttle orbiter on a Boeing 747 carrier plane on August 12, 1977, and the first orbital test flight of a complete, crewed Space Shuttle, consisting of the orbiter, an external fuel tank, and two solid rocket boosters, on April 12, 1981. The designers underestimated the time and cost of refurbishment between flights, which reduced the cost benefit of its reusability. They also overestimated its safety: two of the fleet of five orbiters were lost in fatal flight accidents: one during launch, due to failure of a solid rocket booster seal; and one on reentry, due to launch damage of a wing heat shield. The Air Force was also supposed to use the Shuttle to launch its military payloads, but shunned it in favor of its expendable launchers after the first Shuttle loss. NASA ceased production of its Apollo spacecraft and Saturn IB launcher, and used the Shuttle as its orbital workhorse until 2011, then retired it due to the safety concern. Originally, more than 150 flights over a 15-year operation were expected; actually, the Shuttles made 135 flights in the 30-year lifespan of the series. The Soviets interpreted the Shuttle as a military surveillance vehicle, and decided they had to develop their own shuttle, which they named Buran, beginning in 1974. They copied the aerodynamic design of NASA's Shuttle orbiter, which they strapped to the side of their expendable, liquid hydrogen-fueled Energia launcher.
Sources: en.wikipedia.org
Selank is a synthetic peptide made of seven amino acids. It is modeled on tuftsin, a natural tetrapeptide, with an added three-residue tail. It is not a small-molecule drug.
It originates from research in Russia, associated with the Institute of Molecular Genetics of the Russian Academy of Sciences. The first descriptions date to the mid-1990s. Most published studies come from Russian laboratories.
No, Selank itself does not occur naturally. Its backbone is based on tuftsin, which is produced in the body, but the seven-residue version is a synthetic construct. It is supplied as a manufactured peptide.
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.