A practical reference on Tuftsin analogue: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-06-23. Anything still debated is marked as such rather than presented as settled.
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.
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.
Peptide bonds are vulnerable to protease attack, and Selank is no exception. Measured half-life in serum is short, on the order of minutes in several reports, which explains why intranasal administration is the common route described in the literature. Absorption across the nasal mucosa partially bypasses first-pass hepatic metabolism. Quantitative data on human bioavailability remain limited and are difficult to compare across studies.
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.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Lyophilised solid form |
| Solubility class | Freely soluble in water | Hydrophilic heptapeptide |
| Dry storage temperature | -20 degrees Celsius or lower | Sealed, desiccated, protected from light |
| Solution storage | 2 to 8 degrees Celsius short term | Avoid repeated freeze-thaw cycles |
| Common identification method | Reversed-phase HPLC with mass spectrometry | Confirms purity and molecular mass |
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.
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.
Development work on the compound began in the 1980s and 1990s at the Institute of Molecular Genetics in Moscow, within the same research programme that produced the peptide Semax. Early investigators sought a tuftsin derivative with improved resistance to enzymatic breakdown and with activity in the central nervous system after peripheral administration. Most of the primary literature from this period was published in Russian, a factor that still shapes how easily the findings can be checked by outside groups.
Naming for this compound is not fully standardised in English sources. The spelling Selanc appears in some transliterations, and catalogue entries may instead list the peptide sequence itself as the identifier. Reference material sometimes groups it with other short synthetic peptides studied for behavioural effects, which can create confusion when citations are compared. Distinguishing the exact sequence from related tuftsin analogues is therefore a practical first step when reviewing any dataset or specification sheet.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, frequently abbreviated as TKPRPGP. It was designed as a structural analogue of tuftsin, a naturally occurring tetrapeptide released by enzymatic cleavage of the immunoglobulin heavy chain. The two additional proline residues at the C-terminal end extend the parent chain and change how the molecule behaves in solution. The free peptide has a calculated molecular mass of approximately 751.9 g/mol and is generally supplied as a lyophilised white to off-white powder.
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.
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.
Lyophilized material is generally stable for extended periods when kept dry at or below minus twenty degrees Celsius. Working solutions are less stable, and common practice is to aliquot and freeze them so that repeated freeze-thaw cycles are avoided. Aqueous solutions are sensitive to pH extremes and to microbial growth, so short-term storage at refrigerator temperature is typical. Oxidation and hydrolysis are the principal degradation routes. Reconstitution with sterile water or a mild buffer is standard, and solutions should be protected from light.
Regulatory treatment varies by jurisdiction. In Russia the compound is a registered prescription product, while in the European Union and the United States it is generally handled as a research chemical without a marketing authorization. Suppliers therefore operate outside pharmaceutical oversight, and buyers rely on supplier documentation for purity and identity claims. Chain of custody and third-party testing are the main verification tools. Analysts note that the absence of a pharmacopoeial monograph for research-grade material limits standardization across vendors.
== History == In the 18th century, William Withering discovered that arsenic trioxide, when used in small doses, exhibited therapeutic effects. During the same period, Thomas Fowler prepared a 1% solution of arsenic and potassium carbonate, which was used to treat skin diseases (primarily psoriasis) until the 20th century. An arsenic-based drug, arsphenamine, was also developed for the treatment of syphilis, synthesized by Paul Ehrlich, though it was eventually replaced by penicillin. Arsenic compounds were widely used to treat various diseases in the 19th and early 20th centuries. The first reports of the anticancer activity of arsenic trioxide date back to 1878, when a report from Boston City Hospital described Fowler's solution lowering leukocyte levels in the blood of two healthy individuals and one patient. Arsenic trioxide continued to be used in the treatment of leukemia until the introduction of radiotherapy. It made a resurgence in the 1930s when the first studies confirmed the high efficacy of arsenic trioxide in treating chronic myelogenous leukemia. In the late 1960s, physicians working at the Harbin Medical Academy in China were sent to a center focusing on traditional Chinese medicine, where they used a melanoma ointment, with arsenic as its main ingredient. At that time, the arsenal of anticancer drugs was limited, prompting doctors to experiment with arsenic. Early trials used oral administration, but it showed strong toxic effects. In March 1971, the first trials of intravenous arsenic began, which showed significantly lower toxicity.
The targeting of hospitals, as well as religious sites, constitutes a war crime. Lebanese health minister Firass Abiad said that 163 rescuers and health workers were killed and 273 others were injured in Lebanon since the start of Israel–Hezbollah conflict. Human Rights Watch stated that Israel's "repeated" attacks on medical workers and healthcare facilities were apparent war crimes. The IDF shelled Meiss Ej Jabal Hospital, injuring a doctor on 10 November 2023. The missiles did not explode but caused damage to the emergency department and several cars. Lebanon's Ministry of Public Health condemned the attack, saying that "Israeli authorities were fully responsible for this unjustifiable act, which would have led to catastrophic results", and called for an investigation. Days before, four people were reportedly injured after an Israeli bombing that hit two ambulances. The Lebanese National News Agency said that an Israeli drone strike hit two ambulances belonging to the Risala Scout Association, which is affiliated with the Amal Movement. On 26 December 2023, an anti-tank missile shot by Hezbollah fighters from Lebanon damaged a shed in a church compound in Iqrit, but not the church itself, wounding an elderly civilian. As IDF troops and medical services were working to evacuate him, they were hit by further missiles, which resulted in nine soldiers being wounded, one of them seriously. On 11 January 2024, the IDF conducted strikes in the town of Hanine and targeted an emergency center affiliated with the Hezbollah-linked Islamic Health Authority.
==== Treatment ==== Treatment involves immediate inhalation of amyl nitrite, injections of sodium nitrite, or administration of 4-dimethylaminophenol in combination with inhalation of pure oxygen, administration of bronchodilators to overcome eventual bronchospasm, and in some cases hyperbaric oxygen therapy (HBOT). HBOT has clinical and anecdotal support.
=== Metabolism === Methocarbamol is the carbamate derivative of guaifenesin, but does not produce guaifenesin as a metabolite, because the carbamate bond is not hydrolyzed metabolically; its metabolism is by Phase I ring hydroxylation and O-demethylation, followed by Phase II conjugation. All the major metabolites are unhydrolyzed carbamates. Small amounts of unchanged methocarbamol are also excreted in the urine.
Sources: en.wikipedia.org
Food noise is persistent and intrusive thoughts about food even when food security is not under threat. Although research is still in the early phase, definitions of food noise have emerged, and evidence suggests that food noise is distinct from hunger, food addiction, and food preoccupation. Instead, patients experiencing food noise report constantly ruminating about eating – when to eat, whether they are eating the right types of foods, or whether they are eating the right amount – or having self-recriminating thoughts about their relationship with food. These thoughts have a high cognitive burden and can cause distress, and it has been suggested that food noise may be a reason some people struggle to lose weight. For example, according to WW International, persistent food-related thoughts can make it difficult to adhere to a nutrition or exercise plan and make healthy food choices.
== Biological role and toxicity == Dichloroacetylene causes severe neurological disorders, among other problems. Main route of human exposure to dichloroacetylene has been the breakdown of trichloroethylene in presence of alkali hydroxides, historically during trichloroethylene anaesthesia when soda lime was used. Humans exposed to dichloroacetylene showed symptoms such as nausea, vomiting, loss of appetite, headache, facial nervous and muscular issues, and formation of herpes-like lesions on the face. Some people reported itching around the eyes and pain around the jaw. It affects the trigeminal nerve in particular and over-exposure could be fatal. Studies on male rats and rabbits have shown that inhalation of dichloroacetylene can cause tubular necrosis, focal necrosis, and other nephrotoxic effects. Additionally, the rabbits that were given dichloroacetylene experienced hepatotoxic and neuropathological effects. Inhalation of dichloroacetylene also causes benign tumors of the livers and kidneys of rats. The chemical also caused increased instances of lymphomas. It also causes weight loss in animals. 3.5% of a dose of dichloroacetylene remains in the corpses of male Wistar rats. The LC50s of mice exposed to dichloroacetylene are 124 parts per million for a 1-hour exposure by inhalation and 19 parts per million for a 6-hour exposure by inhalation. The chemical is ingested primarily through glutathione-dependent systems. Glutathione also reacts with it. Hepatic and renal glutathione S-transferases serve as catalysts to this reaction.
From the mid-1980s onward, the media reported "roid rage" as a side effect of AAS. A 2005 review determined that some, but not all, randomized controlled studies have found that AAS use correlates with hypomania and increased aggressiveness, but pointed out that attempts to determine whether AAS use triggers violent behavior have failed, primarily because of high rates of non-participation. A 2008 study on a nationally representative sample of young adult males in the United States found an association between lifetime and past-year self-reported AAS use and involvement in violent acts. Compared with individuals that did not use steroids, young adult males that used AAS reported greater involvement in violent behaviors even after controlling for the effects of key demographic variables, previous violent behavior, and polydrug use. A 1996 review examining the blind studies available at that time also found that these had demonstrated a link between aggression and steroid use, but pointed out that with estimates of over one million past or current steroid users in the United States at that time, an extremely small percentage of those using steroids appear to have experienced mental disturbance severe enough to result in clinical treatments or medical case reports. The relationship between AAS use and depression is inconclusive. A 1992 review found that AAS may both relieve and cause depression, and that cessation or diminished use of AAS may also result in depression, but called for additional studies due to disparate data.
Sources: en.wikipedia.org
During protests against ICE operations in Portland, United States, some protesters flew the flag. The flag also saw use during the anti-Trump No Kings 2.0 protests in October 2025, e.g. in Los Angeles, Miami, and Spokane. In Mexico in November 2025, the flag was among various symbols used by a group identifying itself as "Generation Z Mexico", who is against drug violence that claims tens of thousands of Mexican lives each year and the security policies of Mexican president Claudia Sheinbaum. Former Mexican president Vicente Fox wore a T-shirt emblazoned with the symbol while attending the protests. Bulgarians protesting against increases in pension and social security payments in November–December 2025 used the flag. The flag was seen during the "Flamingo Revolution" in Albania. In August 2026, the Straw Hat Pirates' Jolly Roger was spray-painted on the National Monument on Dam Square in Amsterdam, alongside the phrases "Time to wake up!" and "Stop the human trafficking".
=== Doping in sport === There was a case in the World Anti-Doping Agency practice in 2007, when an athlete, who reportedly consumed Yohimbine prior to a given athletic event, was later tested positive for 19-norandrosterone, which is a prohibited substance. However, WADA did not yet list Yohimbine (which can come into a body via an energy drink, also in a form of pre-workout supplement or fat burner) as a prohibited substance, nor did it confirm that its use can increase the endogenous level of anabolic steroids, in particular of 19-norandrostenedione and testosterone.
== Origin of the word "Radurisation" == The word "radurisation" is derived from radura, combining the initial letters of the word "radiation" with the stem of "durus", the Latin word for hard, lasting.
The third-highest official and the head of government is the chancellor, who is appointed by the Bundespräsident after being elected by the party or coalition with the most seats in the Bundestag. The chancellor, who has been Friedrich Merz since 2025, is the head of government and exercises executive power through his Cabinet. Since 1949, the party system has been dominated by the centre-right Christian Democratic Union and the centre-left Social Democratic Party. So far every chancellor has been a member of one of these parties. However, the smaller liberal Free Democratic Party and Alliance 90/The Greens have also been junior partners in coalition governments. Since 2007, the democratic socialist party The Left has been a staple in the German Bundestag, as has the far-right Alternative for Germany since 2017.
Sources: en.wikipedia.org
Dry powder is normally held at -20 degrees Celsius or below in a sealed, light-protected container with desiccant. Brief room-temperature handling during weighing is generally tolerated. Storage instructions vary between suppliers, so the accompanying certificate of analysis should be followed.
Reversed-phase HPLC establishes purity, while mass spectrometry confirms the expected molecular mass. Sequence confirmation may use tandem mass spectrometry or peptide mapping. A certificate of analysis typically reports these results alongside the analytical method applied.
In Russia it is a registered medicine available by prescription. In many other countries it is not approved for human use and is supplied only as a research chemical. Import and possession rules differ by jurisdiction, and buyers are responsible for checking local requirements.
Dry powder is best kept sealed, protected from light, and held at minus 20 degrees Celsius or below. Desiccant packaging helps limit moisture uptake because the material is hygroscopic. A sealed vial should be allowed to equilibrate to room temperature before opening to reduce condensation.