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 2026-02-11. Where a claim depends on a specific study, the study is described rather than over-claimed.
Lyophilized selank is normally supplied as a dry powder and is considered stable for extended periods when kept cold and dry. Moisture uptake is the main practical threat, because absorbed water promotes both hydrolysis and aggregation in the solid state. Vials are usually warmed to room temperature before opening so that condensation does not form on the powder. Supplier documentation commonly specifies -20 °C for routine storage, with -80 °C used for material intended to be archived for years.
Once dissolved, the peptide is markedly less stable than the dry powder. Aqueous solutions are subject to backbone hydrolysis and to microbial growth when they are handled without sterile technique. Buffered solutions near neutral pH are common for short-term laboratory work, while acidic conditions are sometimes used to improve solubility. Analytical laboratories generally prepare working solutions fresh rather than storing them, and a residual water film left in a reopened vial can seed degradation even when the container appears dry.
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.
Naming conventions place Selank in the same research family as Semax, another Russian-developed peptide investigated for cognitive effects. The two compounds share a lineage but differ in sequence and in the biological systems proposed as their targets. Semax descends from ACTH fragments, whereas Selank descends from tuftsin. Publications sometimes identify Selank by its full peptide sequence or by laboratory codes rather than one uniform trade name. Because replication outside Russia is limited, reports on its properties are best read alongside the study design and the purity of the material tested.
| Property | Value | Notes |
|---|---|---|
| Typical purity specification | 95 percent or higher by RP-HPLC | Area percentage of the main peak |
| Identity confirmation | Electrospray ionization mass spectrometry | Observed mass compared with the theoretical value near 751.9 Da |
| Recommended dry storage | -20 °C, desiccated | -80 °C for multi-year archival material |
| Solution handling | Prepare fresh; avoid long storage | Sterile filtration reduces microbial load |
| Common synonyms | TKPRPGP; TP-7 | Sequence code and laboratory designation used interchangeably |
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.
Peptide stability depends strongly on temperature, moisture, and pH. Lyophilized Selank is generally most stable when stored cold and dry, with freezer temperatures commonly used for long-term storage. In solution, the compound is susceptible to hydrolysis and to microbial growth if it is not handled aseptically. The C-terminal proline-rich extension appears to slow enzymatic cleavage relative to tuftsin, though quantitative degradation rates vary with the matrix and the conditions tested. Published stability data specific to Selank remain sparse.
Regulatory status differs sharply by region. Selank holds a Russian marketing authorization, where it is supplied mainly as nasal drops, while authorities elsewhere have not approved it for medical use. Material sold internationally is therefore usually labeled as a research chemical rather than a medicine. Peer-reviewed publications come predominantly from Russian laboratories, and sample sizes are generally small. Whether the compound produces comparable effects under independent, well-controlled replication remains an open question that the broader literature has not settled.
Selank is a synthetic heptapeptide developed in Russia as a structural analogue of tuftsin, a naturally occurring immunomodulatory tetrapeptide. Its sequence, Thr-Lys-Pro-Arg-Pro-Gly-Pro, keeps the tuftsin core at the N-terminus and appends a Pro-Gly-Pro tail. Researchers at the Institute of Molecular Genetics in Moscow synthesized the compound during the 1990s while searching for peptides with combined anxiolytic and immunomodulatory activity. The added tail was intended to resist enzymatic cleavage and prolong the molecule's presence in circulation.
==== Poverty ==== The U.S. Census Bureau's Statistical Abstract of the United States: 2012 ranks Detroit first among all 71 U.S. cities for which rates were calculated in percentage of the city's population living below the poverty level. The individual rate living below the poverty level is 36.4%; the family rate is 31.3%.
=== pH === According to one lab test manual normal pH range is 7.2–8.2; WHO criteria specify normal as 7.2–7.8. Acidic ejaculate (lower pH value) may indicate one or both of the seminal vesicles are blocked. A basic ejaculate (higher pH value) may indicate an infection. A pH value outside of the normal range is harmful to sperm and can affect their ability to penetrate the egg. The final pH results from balance between pH values of accessory glands secretions, alkaline seminal vesicular secretion and acidic prostatic secretions.
The nitrogen rule states that organic compounds containing exclusively hydrogen, carbon, nitrogen, oxygen, silicon, phosphorus, sulfur, and the halogens either have (1) an odd nominal mass that indicates an odd number of nitrogen atoms are present or (2) an even nominal mass that indicates an even number of nitrogen atoms in the molecular formula of the neutral compound. The nitrogen rule is not a rule as much as a general principle which may prove useful when attempting to solve organic mass spectrometry structures.
==== Chloroplast genome reduction and gene transfer ==== Over time, many parts of the chloroplast genome were transferred to the nuclear genome of the host, a process called endosymbiotic gene transfer. As a result, the chloroplast genome is heavily reduced compared to that of free-living cyanobacteria. Chloroplasts may contain 60–100 genes whereas cyanobacteria often have more than 1500 genes in their genome. Recently, a plastid without a genome was found, demonstrating chloroplasts can lose their genome during endosymbiotic the gene transfer process. Endosymbiotic gene transfer is how we know about the lost chloroplasts in many CASH lineages. Even if a chloroplast is eventually lost, the genes it donated to the former host's nucleus persist, providing evidence for the lost chloroplast's existence. For example, while diatoms (a heterokontophyte) now have a red algal derived chloroplast, the presence of many green algal genes in the diatom nucleus provide evidence that the diatom ancestor had a green algal derived chloroplast at some point, which was subsequently replaced by the red chloroplast. In land plants, some 11–14% of the DNA in their nuclei can be traced back to the chloroplast, up to 18% in Arabidopsis, corresponding to about 4,500 protein-coding genes. There have been a few recent transfers of genes from the chloroplast DNA to the nuclear genome in land plants. Of the approximately 3000 proteins found in chloroplasts, some 95% of them are encoded by nuclear genes.
Sources: en.wikipedia.org
==== Anger at Sanlu ==== The case has brought anger and resentment towards milk producers and sowed uncertainty and confusion amongst the population. Queues formed outside Sanlu's offices for refunds. The Sanlu website was hacked several times and its name as displayed in the header bar changed to 三聚氰胺集团 ("The Melamine Group") in a play of words on the character "三" (number 3), which is the first word of Sanlu's Chinese name: 三鹿 (Three Deer); "Melamine" was also added as a product name by a hacker. As has been increasingly common practice, web users vented their anger on internet bulletin boards. Prevalent food scares have increased the number of online parodies circulated by netizens. Before the government began offering free medical treatment, some parents had reportedly spent small fortunes on medical care for their sick children. Children who fell ill before the scandal broke on 12 September were not entitled to free medical care offered by the State. Parents of two such victims, one from Henan and one from Guangdong, filed writs against Sanlu despite government pressure. Parents of the Henan child had claimed ¥150,000 for medical, travel and other expenses incurred after their child developed kidney stones. On 20 October, the parents of one baby who died from contaminated milk appealed to New Zealand for justice on TV ONE. A total of nine cases were filed against Sanlu in Shijiazhuang.
Carboxypeptidase E (CPE), also known as carboxypeptidase H (CPH) and enkephalin convertase, is an enzyme that in humans is encoded by the CPE gene. This enzyme catalyzes the release of C-terminal arginine or lysine residues from polypeptides. CPE is involved in the biosynthesis of most neuropeptides and peptide hormones. The production of neuropeptides and peptide hormones typically requires two sets of enzymes that cleave the peptide precursors, which are small proteins. First, proprotein convertases cut the precursor at specific sites to generate intermediates containing C-terminal basic residues (lysine and/or arginine). These intermediates are then cleaved by CPE to remove the basic residues. For some peptides, additional processing steps, such as C-terminal amidation, are subsequently required to generate the bioactive peptide, although for many peptides the action of the proprotein convertases and CPE is sufficient to produce the bioactive peptide.
== Consumer products == There have been cases of severe contact dermatitis which was likely related to a dimethyl fumarate contact allergy of newly acquired sofas and chairs. Dimethyl fumarate has been found to be an allergic sensitizer at very low concentrations, producing eczema by contact allergy that is difficult to treat. Concentrations as low as 1 ppm (parts-per-million) may produce allergic reactions in the most severe cases. There are only a handful of equally potent sensitisers. The sensitizing risk was brought to public attention by the "poison chair" incident, where Chinese manufacturer Linkwise produced two-seater sofas with dimethyl fumarate sachets inside to inhibit mould while they were in storage or transport. In Finland where the chairs were sold from 2006 to 2007, 60 users sustained serious rashes. The cause was identified as dimethyl fumarate-induced allergic reaction by Tapio Rantanen from Finland and his original article became the cover story in the July 2008 issue of the British Journal of Dermatology. In the United Kingdom, sofas sold by Argos, Land of Leather and Walmsley Furnishing containing the chemical caused over a hundred injuries. Argos withdrew the sofas from stores and contacted buyers to collect those that had been sold — with Land of Leather withdrawing the sofas without notifying buyers and Walmsley saying they had removed the sachets from sofas they sold after the danger came to light. The danger came to public attention in 2008 when the BBC Watchdog programme alerted consumers to the sofas.
In the event of involvement of the sympathetic tracts in the brainstem, a partial Horner's syndrome may develop; this is the combination of a drooping eyelid, constricted pupil, and an apparently sunken eye on one side of the face. If the dissection of the artery extends to the part of the artery that lies inside the skull, subarachnoid hemorrhage may occur (1% of cases). This arises due to rupture of the artery and accumulation of blood in the subarachnoid space. It may be characterized by a different, usually severe headache; it may also cause a range of additional neurological symptoms. 13–16% of all people with vertebral or carotid dissection have dissection in another cervical artery. It is therefore possible for the symptoms to occur on both sides, or for symptoms of carotid artery dissection to occur at the same time as those of vertebral artery dissection. Some give a figure of multiple vessel dissection as high as 30%.
Chlorothalonil (2,4,5,6-tetrachloroisophthalonitrile) is an organic compound mainly used as a broad spectrum, nonsystemic fungicide, with other uses as a wood protectant, pesticide, acaricide, and to control mold, mildew, bacteria, algae. Chlorothalonil-containing products are sold under the names Bravo, Echo, and Daconil. It was first registered for use in the US in 1966. In 1997, it was the third most used fungicide in the US, behind only sulfur and copper, with 12 million pounds (5.4 million kilograms) used in agriculture that year. Including nonagricultural uses, the United States Environmental Protection Agency (EPA) estimates, on average, almost 15 million lb (6.8 million kg) were used annually from 1990 to 1996.
Sources: en.wikipedia.org
=== Seed germination === There are two types of seed within each pod – reddish-dark and dark (black). The ratio between these seeds varies from 1:20 to 1:5, with darker seeds outnumbering lighter seeds. Reddish-dark seeds have a thinner coat and they germinate earlier than black seeds that have not first been acid treated. "Dark seeds have a harder seed coat and require various pretreatments to ensure good germination rates." Although the seeds' usual germination rate has been reported at 75%, germination can be improved by scalding for about 7 minutes, then soaking seeds in hot water overnight prior to planting. Locust tree seedlings "can be established vegetatively in nursery beds by grafting or budding, or by rooting adult cuttings." These methods have shown good results in 11- to 25-year-old trees in Burkina Faso and Nigeria.
It also provides easier development capability for the system suppliers at each end site. All pathology tests and profiles are coded from the Read Codes, a clinical terminology originally developed by a General Practitioner, James Read, to describe all aspects of healthcare for his own use but subsequently adopted and further developed by the NHS. A small subset of the complete set of READ codes (which itself numbered 89,616 discrete codes by the time of its final update in 2016) was developed specifically for this project and then subsequently maintained as the Pathology Bounded Code List (PBCL). By its final release, also in 2016, this PBCL subset had grown to offer 3352 uniquely codable tests that can be requested and resulted. The PBCL content has since been mirrored into the UK Extension of SNOMED Clinical Terms (CT), an enhancement of the SNOMED CT (Systematized Nomenclature of Medicine) classification scheme, but the EDIFACT message syntax can not carry them due to their character length. The data must therefore be sent using the original 5-Character READ codes from the PBCL and then transcoded to a final SNOMED target code by the receiving system. The electronic delivery of test results from clinical laboratories to clinical users is rightly seen as a service that can provide clinical benefit by speeding up diagnostic processes and ensuring accurate and timely delivery of critical clinical information. Such electronic transfers were begun in the UK and Europe in the early 1990s using various message standards including ASTM E1238.
=== 1990-1991: Razum I Bezumlje and first major breakup === The band decided to continue without Pokrovac. They recruited new guitarist Ivan Dujmić, and in 1990, they released their first studio album, "Razum I Bezumlje", on the independent label Search & Enjoy. The album displayed a raw and aggressive punk-influenced garage rock style, and featured several live staples such as "Iz Sve Snage", "Zbunjen I Ošamućen", "Lutak Iskrivljenog Lica", "Nikada Te Neću Zaboraviti" and "Putujem". Bare wrote the lyrics, while Duspara wrote all of the music on the album. The album was proclaimed rock album of the year by domestic audiences. However, the band's success was suddenly interrupted by the start of the Croatian War of Independence, with Vinkovci being one of the frontlines. The band soon broke up.
Perchlorate ions, a common water contaminant in the USA due to the aerospace industry, has been shown to reduce iodine uptake and thus is classified as a goitrogen. Perchlorate ions are a competitive inhibitor of the process by which iodide is actively deposited into thyroid follicular cells. Studies involving healthy adult volunteers determined that at levels above 0.007 milligrams per kilogram per day (mg/(kg·d)), perchlorate begins to temporarily inhibit the thyroid gland's ability to absorb iodine from the bloodstream ("iodide uptake inhibition", thus perchlorate is a known goitrogen). The reduction of the iodide pool by perchlorate has dual effects – reduction of excess hormone synthesis and hyperthyroidism, on the one hand, and reduction of thyroid inhibitor synthesis and hypothyroidism on the other. Perchlorate remains very useful as a single dose application in tests measuring the discharge of radioiodide accumulated in the thyroid as a result of many different disruptions in the further metabolism of iodide in the thyroid gland. Treatment of thyrotoxicosis (including Graves' disease) with 600–2,000 mg potassium perchlorate (430-1,400 mg perchlorate) daily for periods of several months or longer was once common practice, particularly in Europe, and perchlorate use at lower doses to treat thyroid problems continues to this day. Although 400 mg of potassium perchlorate divided into four or five daily doses was used initially and found effective, higher doses were introduced when 400 mg/day was discovered not to control thyrotoxicosis in all subjects.
When injected secretly, it does not have any effect, whereas standard pain drugs have an effect, even if they are administered without the subject's awareness. The supposed mechanism is an enhancement of the neural pathways of expectation as a result of dopamine and endogenous opioids being suddenly released throughout numerous structures of the brain and spinal cord. The ventral tegmental area is the structure believed to mediate proglumide's analgesic and euphoric effects, however dozens of areas with a wide range of physical and psychological functions are implicated in the mediation of the placebo effect (this accounts for proglumide's ability to produce physically measurable effects on vital signs such as heart rate, blood pressure, respiration rate, and tidal volume which cannot be accounted for by its clinically insignificant δ-opioid affinity.
Sources: en.wikipedia.org
Sealed, desiccated storage at -20 °C or colder is the standard recommendation for research-grade material. Vials should reach room temperature before they are opened, which limits condensation. Repeated temperature cycling is discouraged.
A reported purity value reflects the share of the main peak in one chromatographic run and says nothing about identity. Confirming that the expected sequence is present requires a separate measurement such as mass spectrometry. Purity and identity are distinct questions.
A mass spectrum reports the molecular masses present in a sample and shows whether they match the value expected for selank, near 751.9 Da. It also flags common artifacts such as truncation or adduct formation. It does not establish correct stereochemistry or complete sequence order on its own.
Selank is a synthetic heptapeptide designed as a stabilized analog of the natural tetrapeptide tuftsin. It has been investigated mainly for anxiolytic and cognitive effects. It is not an approved pharmaceutical in most countries.