A practical reference on peptide purity: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2025-11-27. Anything still debated is marked as such rather than presented as settled.
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.
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.
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.
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.
| 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 |
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 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.
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.
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.
Amanita virosa is highly toxic, and has been responsible for severe mushroom poisonings. Eating just one cap of A. virosa is enough to kill an adult human. The symptoms of poisoning generally come several hours after consumption, a delay which may make treatment more difficult. Fruit bodies contain both amatoxins and phallotoxins. Amatoxins consist of at least eight compounds with a similar structure, that of eight amino-acid rings; they were isolated in 1941 by Heinrich O. Wieland and Rudolf Hallermayer of LMU Munich. Of the amatoxins, α-Amanitin is the chief component and along with β-Amanitin is probably responsible for the toxic effects. Their major toxic mechanism is the inhibition of RNA polymerase II, a vital enzyme in the synthesis of messenger RNA (mRNA), microRNA, and small nuclear RNA, (snRNA). Without mRNA essential protein synthesis and hence cell metabolism cease and the cell dies. The liver is the principal organ affected, as it is the organ which is first encountered after absorption in the gastrointestinal tract, though other organs, especially the kidneys, are susceptible. Phallotoxins consist of at least seven compounds, all of which have seven similar peptide rings. Phalloidin was isolated in 1937 by Feodor Lynen, Heinrich Wieland's student and son-in-law, and Ulrich Wieland of LMU Munich. Though phallotoxins are highly toxic to liver cells, they have since been found to have little input into the destroying angel's toxicity as they are not absorbed through the gut. Furthermore, phalloidin is also found in the edible Amanita rubescens.
=== Ribosomal diseases and cancer === Ribosomopathies are congenital human disorders resulting from defects in ribosomal protein or rRNA genes, or other genes whose products are implicated in ribosome biogenesis. Examples include X-linked Dyskeratosis congenita (X-DC), Diamond–Blackfan anemia, Treacher Collins syndrome (TCS) and Shwachman–Bodian–Diamond syndrome (SBDS). SBDS is caused by mutations in the SBDS protein that affects its ability to couple GTP hydrolysis by the GTPase EFL1 to the release of eIF6 from the 60S subunit.
==== Religion ==== Talarico has been described as a progressive Christian, but has objected to the term, saying he believes not in "a progressive or conservative Christianity" but in a "Biblical Christianity." Talarico has cited his faith and the teachings of Jesus as the reason for launching his political career. He said he was following the commandments to love God and one's neighbor. He said politics is "another word for how we treat our neighbors". Talarico is a critic of Christian nationalism and has called it "a cancer on our religion". He said, "there's nothing Christian about Christian nationalism". In a 2023 guest sermon, Talarico called Christian nationalism "the worship of power—social power, economic power, political power, in the name of Christ". He has said Christian nationalists have turned Jesus "into a gun-toting, gay-bashing, science-denying, money-loving, fear-mongering fascist" and that it is "incumbent on all Christians to confront it and denounce it".
Minoxidil — first-line, low dose topical drug for hair loss, can also be used orally at a high dose for hypertension; oral minoxidil has been implicated in heart problems including pericardial effusion. Monoamine oxidase inhibitors — used for treatment-resistant depression; may have potentially lethal dietary and drug interactions which may trigger hypertensive crisis and/or serotonin syndrome. Thalidomide — originally prescribed for morning sickness, withdrawn in 1961 owing to widespread incidence of severe birth defects (phocomelia or tetraamelia) after prenatal use by pregnant women; approved by the US Food and Drug Administration for erythema nodosum leprosum (ENL) in 1998, and new cases of multiple myeloma (administered with dexamethasone) in 2008; also used "off-label" for rare cancers; can cause multiple severe side effects and cannot be prescribed to pregnant women. Tolcapone — used in patients with Parkinson's disease who are not appropriate candidates for other adjunctive therapies; use is restricted due to hepatotoxicity. Vigabatrin — used for extreme treatment-resistant epilepsy; carries risk of permanent vision loss.
=== National guidelines === In 2011, the USDA launched MyPlate, which did not distinguish between kinds of meat, but did recommend eating at least 8 oz (230 g) of fish each week. In 2011, the Harvard School of Public Health launched the Healthy Eating Plate in part because of the perceived inadequacies of the USDA's recommendations. The Healthy Eating Plate encourages consumers to avoid processed meat and limit red meat consumption to twice a week because of links to heart disease, diabetes, and colon cancer. To replace these meats it recommends consuming fish, poultry, beans, or nuts. The National Heart Foundation of New Zealand recommends that one should aim to reduce consumption of red meat below 350g per week and replace meat with plant sources of protein.
Sources: en.wikipedia.org
== Research == Zalsupindole, as well as related drugs such as tabernanthalog (TBG; DLX-007), DLX-159, DLX-2270, and JRT, are licensed by Delix Therapeutics and are being developed for treatment of neuropsychiatric disorders such as depression and schizophrenia. As of January 2026, zalsupindole is in phase 1 clinical trials for major depressive disorder and other central nervous system disorders. Phase 1a and 1b trials have been completed and results reported. A phase 2 trial is being planned and has been cleared by the FDA for at home administration.
In 1987, Toni Schumacher recounted a huge amount of hormones, pills and injections (Liesen, head of the doctor team, injected 3,000 himself) being used by national players during the World Cup 1986 in Mexico (see next chapter). Argentina took "speedy coffee" before the qualifier for the 1994 World Cup against Australia, at least this is what Maradona said in May 2011. It should make them run faster, but also caused sleeping problems. He also found it suspicious that only the deciding match (against Australia) had no anti-doping control. Grondona, chairman of AFA back then, responded that there were no tests because Maradona, who already had a drug history, might not have passed. Maradona tested positive in the world cup. Immediately after the World Cup 1998, all of the drug testing samples were destroyed. If the same had happened in the Tour de France, former WADA director Alain Garnier argued that Lance Armstrong would not have been caught. Marie-George Buffet, sports minister at that time, also recalls that she felt pressurised when she initiated an unannounced test in December 1997. There were no more unannounced tests after that. Jean-Pierre Paclet, physician of Les Bleus in 1998, mentions "abnormal haematocrit values" in his book. Gary Neville, former English international, recalled that "some of the players started taking injections from ... a Frenchman called Dr Rougier". After some felt an energy boost, there was "a queue to see the doctor before the Argentina match".
Genes express their functional effect through the production of proteins, which are molecules responsible for most functions in the cell. Proteins are made up of one or more polypeptide chains, each composed of a sequence of amino acids. The DNA sequence of a gene is used to produce a specific amino acid sequence. This process begins with the production of an RNA molecule with a sequence matching the gene's DNA sequence, a process called transcription. This messenger RNA molecule then serves to produce a corresponding amino acid sequence through a process called translation. Each group of three nucleotides in the sequence, called a codon, corresponds either to one of the twenty possible amino acids in a protein or an instruction to end the amino acid sequence; this correspondence is called the genetic code. The flow of information is unidirectional: information is transferred from nucleotide sequences into the amino acid sequence of proteins, but it never transfers from protein back into the sequence of DNA—a phenomenon Francis Crick called the central dogma of molecular biology. The specific sequence of amino acids results in a unique three-dimensional structure for that protein, and the three-dimensional structures of proteins are related to their functions. Some are simple structural molecules, like the fibers formed by the protein collagen. Proteins can bind to other proteins and simple molecules, sometimes acting as enzymes by facilitating chemical reactions within the bound molecules (without changing the structure of the protein itself).
North Korea outside Pyongyang - Special permit required. People are not allowed to leave the capital city, tourists can only leave the capital with a governmental tourist guide (no independent moving). Malaysia. Sabah and Sarawak - Visa not required. These states have their own immigration authorities and passport is required to travel to them, however the same visa applies. Maldives outside Malé - Permission required. Tourists are generally prohibited from visiting non-resort islands without the express permission of the Government of Maldives. Russia. Several closed cities and regions in Russia - Special authorization required. Saudi Arabia Mecca and Medina - Special access required. Non-Muslims and those following the Ahmadiyya religious movement are strictly prohibited from entry. Sudan. Darfur - Separate travel permit is required. Sudan outside Khartoum - All foreigners traveling more than 25 kilometers outside of Khartoum must obtain a travel permit. Tajikistan. Gorno-Badakhshan Autonomous Province - OIVR permit required (15+5 Tajikistani Somoni) and another special permit (free of charge) is required for Lake Sarez. Turkmenistan. Closed cities - A special permit, issued prior to arrival by Ministry of Foreign Affairs, is required if visiting the following places: Atamurat, Cheleken, Dashoguz, Serakhs and Serhetabat. United States. Closed city of Mercury, Nevada, United States - Special authorization is required for entry into Mercury. United States.
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.
Identity is confirmed by matching the retention time in reversed-phase chromatography against a reference standard and by measuring the molecular mass with mass spectrometry. Tandem mass spectrometry or amino acid analysis can verify the sequence of the seven residues. Because the peptide contains no aromatic amino acids, detection at 280 nm is not useful.