heptapeptide raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-03-13 and is reviewed periodically as new material appears.
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 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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Tuftsin analogue |
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Single-letter form: TKPRPGP |
| Molecular formula | C33H57N11O9 | Calculated for the free peptide |
| Molecular weight | About 751.9 g/mol | Derived from the sequence |
| Appearance | White to off-white powder | Typical lyophilised form |
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.
Reverse-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres is the standard purity method. Mass spectrometry, typically electrospray ionisation, confirms identity through the expected mass-to-charge pattern. Amino acid analysis can verify composition independently. Chiral purity requires separate techniques such as derivatisation followed by chromatographic separation, and such data are rarely reported for research-grade material.
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.
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.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, with mass spectrometry used to confirm molecular mass and sequence information. Amino acid analysis and peptide mapping may supplement these methods. Certified reference standards are scarce, and many commercial lots are sold as research chemicals without a pharmacopoeial monograph. Regulatory treatment differs by country: Selank is a registered prescription medicine in Russia, while in the European Union and the United States it is not an approved drug and may fall under research-chemical or unapproved-product frameworks.
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.
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.
== Early life == Darshan Ranganathan was born as Darshan Markan on 4 June 1941 to Vidyavati Markan and Shanti Swarup in Delhi. She was educated in Delhi and received a Ph.D. in chemistry from Delhi University in 1967. First hired as a lecturer, she became head of the Chemistry Department at Miranda College, Delhi, and went on to receive an 1851 Research Fellowship from the Royal Commission for the Exhibition of 1851, to enable her to conduct postdoctoral work at Imperial College London with Professor D.H.R. Barton.
Panic disorder with or without agoraphobia. Body dysmorphic disorder Repetitive self-injurious/self-harming behaviours in those with intellectual disability specifically. The subtype of systemised paranoia characterised by somatic phenomena. Compulsive nail-biting (onychophagia). Cataplexy associated with narcolepsy. This is a TGA and MHRA-labeled indication for clomipramine. Self-bloodletting Premature ejaculation, where it may be more effective than paroxetine Depersonalization-derealization disorder Chronic pain with or without organic disease, particularly headache of the tension type. Developmental stuttering Sleep paralysis, with or without narcolepsy Enuresis (involuntary urinating in sleep) in children. The effect may not be sustained following treatment, and alarm therapy may be more effective in both the short-term and the long-term. Combining a tricyclic (such as clomipramine) with anticholinergic medication may be more effective for treating enuresis than the tricyclic alone. Trichotillomania In combination with lithium and tryptophan for severe, particularly treatment-resistant depression. This combination, in a similar vein, has also been used for clomipramine-resistant obsessive-compulsive disorder. When electro-convulsive therapy is performed alongside this treatment-regime (as may be the case in severe depression and accompanied with thyroxine,) however, great care must be taken with lithium. The overall risk of seizures may have to be weighted against the refractory severity of the current illness and necessity of the amalgamation of treatment(s).
The origin of the modern smallpox vaccine has long been unclear, but horsepox was identified in the 2010s as the most likely ancestor. Edward Jenner had obtained his vaccine from a cow, so he named the virus vaccinia, after the Latin word for cow. Jenner believed that both cowpox and smallpox were viruses that originated in the horse and passed to the cow, and some doctors followed his reasoning by inoculating their patients directly with horsepox. The situation was further muddied when Louis Pasteur developed techniques for creating vaccines in the laboratory in the late 19th century. As medical researchers subjected viruses to serial passage, inadequate recordkeeping resulted in the creation of laboratory strains with unclear origins. By the late 19th century, it was unknown whether the vaccine originated from cowpox, horsepox, or an attenuated strain of smallpox. In 1939, Allan Watt Downie showed that the vaccinia virus was serologically distinct from the "spontaneous" cowpox virus. This work established vaccinia and cowpox as two separate viral species. The term vaccinia now refers only to the smallpox vaccine, while cowpox no longer has a Latin name. The development of whole genome sequencing in the 1990s made it possible to compare orthopoxvirus genomes and identify their relationships with each other. The horsepox virus was sequenced in 2006 and found to be most closely related to vaccinia. In a phylogenetic tree of the orthopoxviruses, horsepox forms a clade with vaccinia strains, and cowpox strains form a different clade.
Sources: en.wikipedia.org
=== Usage of temporary foreign workers === Following the COVID-19 pandemic, Tim Hortons utilized the temporary foreign worker program (TFW) to fill employee vacancies. In December 2025, CBC News reported that the company had lobbied federal politicians to expand the program. In May 2026, Tim Hortons announced that it would seek to "hire local" and reduce its usage of the program, stating that 4,000 of its employees were hired through the TFW program as of 2026.
Secretary of Defense Pete Hegseth said, "We devastated the Iranian nuclear program, but it's worth noting that the operation did not target Iranian troops or the Iranian people." On June 22, Trump said that since the Islamic regime in control of Iran has failed to make Iran great, it should be replaced to "Make Iran Great Again". Later, he posted on social media that their constant anger, hostility, and despair have only led them to ruin. The path they're on offers no hope, only more hardship, "I wish the leadership of Iran would realize that you often get more with honey than you do with vinegar".
The first known archaeological evidence of usage was in Kariandusi (Kenya) and other sites of the Acheulian age (beginning 1.5 million years BP) dated 700,000 BC, although only very few objects have been found at these sites relative to the Neolithic. Manufacture of obsidian bladelets at Lipari had reached a high level of sophistication by the late Neolithic, and was traded as far as Sicily, the southern Po river valley, and Croatia. Obsidian bladelets were used in ritual circumcisions and cutting of umbilical cords of newborns. Anatolian sources of obsidian are known to have been the material used in the Levant and modern-day Iraqi Kurdistan from a time beginning sometime about 12,500 BC. Obsidian artifacts are common at Tell Brak, one of the earliest Mesopotamian urban centers, dating to the late fifth millennium BC. Obsidian was valued in Stone Age cultures because, like flint, it could be fractured to produce sharp blades or arrowheads in a process called knapping. Like all glass and some other naturally occurring rocks, obsidian breaks with a characteristic conchoidal fracture. It was also polished to create early mirrors. Modern archaeologists have developed a relative dating system, obsidian hydration dating, to calculate the age of obsidian artifacts.
=== Home media === The film was released by The Criterion Collection as a Region 1 DVD on 25 November 2008 and on Blu-ray on 10 September 2013. Extras for this version include: digitally restored picture and sound; an interview with John le Carré; scene-specific commentary by director of photography Oswald Morris; a BBC documentary titled The Secret Centre: John le Carré (2000); an interview with Richard Burton from a 1967 episode of the BBC series Acting in the '60s; a 1985 audio interview with director Martin Ritt; a gallery of set designs; the film's theatrical trailer; and a booklet featuring an essay by film critic Michael Sragow.
Sources: en.wikipedia.org
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, commonly written as TKPRPGP. It shares the first four residues with tuftsin and carries three prolines in the chain. The proline-rich tail is the main structural feature that separates it from the parent tetrapeptide.
Selank is a synthetic analogue built on the tuftsin tetrapeptide Thr-Lys-Pro-Arg. Extra proline residues were added to the C-terminus during design work. That modification is intended to make the peptide less vulnerable to rapid enzymatic degradation.
Transliteration from Russian produces variant spellings such as Selanc. Many suppliers avoid the trade-style name entirely and list the peptide sequence. Comparing sequences rather than names is the reliable way to confirm two entries describe the same molecule.
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.