heptapeptide 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 2026-06-25. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Solubility behavior is a practical concern for handling. Selank dissolves readily in water and in common aqueous buffers, which simplifies preparation of working solutions. The choice of solvent, ionic strength, and pH can influence aggregation over time, particularly at higher concentrations. Aqueous solutions are typically sterile-filtered before use. Because stability depends on several variables, storage and handling notes should be treated as general guidance rather than fixed rules, and specific values are best confirmed against a certificate of analysis for each batch.
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.
Selank is a synthetic heptapeptide developed in Russia during the 1990s. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences designed it as a stabilized analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The compound has been studied primarily for its reported anxiolytic and nootropic effects. It remains largely unknown in Western pharmacology and is not approved as a medicine by major regulators such as the FDA or the EMA.
| Property | Value | Notes |
|---|---|---|
| Solubility | Freely soluble in water | Also in aqueous buffers |
| Typical purity (HPLC) | 95 percent or higher | Lot-dependent |
| Dry powder storage | Minus 20 degrees Celsius | Sealed, dry, protected from light |
| Solution storage | 2 to 8 degrees Celsius | Short-term use |
| Identity confirmation | Mass spectrometry | ESI or MALDI-TOF |
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.
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.
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.
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=== Pharmacokinetics === Carisoprodol has a rapid, 30-minute onset of action, with effects lasting around two to six hours. It is metabolized in the liver via the cytochrome P450 oxidase isozyme CYP2C19, excreted by the kidneys, and has about an eight-hour half-life. In patients with low levels of CYP2C19 (poor metabolizers), standard doses can lead to increased concentrations of carisoprodol (up to a fourfold increase). A considerable proportion of carisoprodol is metabolized to meprobamate, a known addictive substance; this could account for the addictive potential of carisoprodol (meprobamate levels reach higher peak plasma levels than carisoprodol itself following administration). It is slightly water-soluble and freely soluble in ethanol, chloroform and acetone. The drug's solubility is practically independent of pH.
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1848: American astronomer Maria Mitchell became the first woman elected to the American Academy of Arts and Sciences; she had discovered a new comet the year before. 1848–1849: English scientist Mary Anne Whitby, a pioneer in western silkworm cultivation, collaborated with Charles Darwin in researching the hereditary qualities of silkworms. 1850: The American Association for the Advancement of Sciences accepted its first women members: astronomer Maria Mitchell, entomologist Margaretta Morris, and science educator Almira Hart Lincoln Phelps.
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Digital artery pressures are measured in the arteries of the fingers before and after the hands have been cooled. A decrease of at least 15 mmHg is diagnostic (positive). Doppler ultrasound to assess blood flow Full blood count may reveal a normocytic anaemia suggesting the anaemia of chronic disease or kidney failure. Blood test for urea and electrolytes may reveal kidney impairment. Thyroid function tests may reveal hypothyroidism. Tests for rheumatoid factor, erythrocyte sedimentation rate, C-reactive protein, and autoantibody screening may reveal specific causative illnesses or an inflammatory process. Anti-centromere antibodies are common in limited systemic sclerosis (CREST syndrome). Nail fold vasculature (capillaroscopy) can be examined under a microscope. To aid in the diagnosis of Raynaud's phenomenon, multiple sets of diagnostic criteria have been proposed. Table 1 below provides a summary of these various diagnostic criteria. Recently, International Consensus Criteria were developed for the diagnosis of primary Raynaud's phenomenon by a panel of experts in the fields of rheumatology and dermatology.
== Structural studies == As of late 2007, 7 structures have been solved for this class of enzymes, with PDB accession codes PDB: 1KHH, PDB: 1P1B, PDB: 1P1C, PDB: 1XCJ, PDB: 1XCL, PDB: 1ZX0, and PDB: 2BLN.
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=== Adverse effects specific to intravenous paracetamol === Intravenous paracetamol has consistently been shown to have hemodynamic effects, reducing systolic, diastolic, and mean arterial blood pressure. In a minority of cases, this side effect has been associated with cardiac arrest. Hypotension is hypothesized to occur due to the addition of mannitol in intravenous formulations of paracetamol, which is done to enhance solubility. Other side effects specific to IV paracetamol include pain at injection site.
With the damage to the core columns, the buckling exterior columns could no longer support the buildings, causing them to collapse. Additionally, the report found the towers' stairwells were not properly reinforced to provide adequate emergency escape for people above the impact zones. NIST concluded that uncontrolled fires in 7 WTC caused floor beams and girders to heat and subsequently "caused a critical support column to fail, initiating a fire-induced progressive collapse that brought the building down."
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In addition to the spin excitation properties of nuclei, it is also possible to study the properties of organic radicals through the same fundamental technique. Unpaired electrons also have a net spin, and an external magnetic field allows for the extraction of similar information through electron paramagnetic resonance (EPR) spectroscopy.
=== Generic names === Ethylestrenol is the generic name of the drug and its INNTooltip International Nonproprietary Name, USANTooltip United States Adopted Name, and BANTooltip British Approved Name, while éthylestrénol is its DCFTooltip Dénomination Commune Française and ethylnandrol is its JANTooltip Japanese Accepted Name. The BANTooltip British Approved Name was formerly ethyloestrenol, but it was eventually changed.
Penetrating trauma is an open wound injury that occurs when an object pierces the skin and enters a tissue of the body, creating a deep but relatively narrow entry wound. In contrast, a blunt or non-penetrating trauma may have some deep damage, but the overlying skin is not necessarily broken and the wound is still closed to the outside environment. The penetrating object may remain in the tissues, come back out the path it entered, or pass through the full thickness of the tissues and exit from another area. A penetrating injury in which an object enters the body or a structure and passes all the way through an exit wound is called a perforating trauma, while the term penetrating trauma implies that the object does not perforate wholly through. In gunshot wounds, perforating trauma is associated with an entrance wound and an often larger exit wound. Penetrating trauma can be caused by a foreign object or by fragments of a broken bone. Usually occurring in violent crime or armed combat, penetrating injuries are commonly caused by gunshots and stabbings. Penetrating trauma can be serious because it can damage internal organs and presents a risk of shock and infection. The severity of the injury varies widely depending on the body parts involved, the characteristics of the penetrating object, and the amount of energy transmitted to the tissues. Assessment may involve X-rays or CT scans, and treatment may involve surgery, for example to repair damaged structures or to remove foreign objects.
Chicago, Illinois (includes Kenosha, Wisconsin) Clarksville, Tennessee Cincinnati, Ohio Columbia, Missouri Columbus, Ohio Dayton, Ohio Detroit, Michigan Indianapolis, Indiana Las Vegas, Nevada Lexington, Kentucky Louisville, Kentucky Minneapolis–St. Paul, Minnesota Nashville, Tennessee New York – New Jersey (includes Allentown, Pennsylvania) Orlando, Florida Phoenix, Arizona (no locations in Phoenix proper) St. Louis, Missouri Louisville and Columbus also house bulk-manufacturing (grocery-store sales, meat, and bun production) divisions. Company headquarters and the Porcelain Steel Buildings division are in Columbus, Ohio. In the late 20th century, White Castle tried expanding into three new cities, Philadelphia, Kansas City, and Cleveland-Akron. Those restaurants closed within several years. After a several decade hiatus, the company returned to the Kansas City area in 1985 only to leave again in 2001. White Castle entered the Cleveland-Akron area in 1987 and then exited in December 2014.
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Reverse-phase HPLC is the usual method and gives a percentage purity value. Mass spectrometry then confirms the molecular mass. Together they provide a basic identity and purity profile for a lot.
Freeze-dried material is kept frozen, often at minus 20 degrees Celsius, and protected from light and moisture. Dissolved peptide is refrigerated for short-term use. Repeated freeze-thaw cycles are avoided.
A certificate of analysis typically lists purity by HPLC, the confirmed mass, appearance, and sometimes water or counter-ion content. It documents results for a specific batch. Details vary by supplier.
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.