If you have been reading about heptapeptide and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2026-05-21. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Route studied | Intranasal | Predominant route in published reports |
| Circulation stability | Short, minutes scale | Peptidases cleave it; the tail slows the process |
| Analytical method | RP-HPLC with mass spectrometry | Used for identity and purity assessment |
| Reported outcome domains | Anxiety and cognitive measures | Derived from small, mostly regional trials |
| Regulatory status | Marketed in Russia | Availability outside that market is limited |
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.
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.
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.
Despite initial successes, however, Gericke realized that the time was not yet ripe for the general technical application and commercial use of hydroponics for producing crops. He also wanted to make sure all aspects of hydroponic cultivation were researched and tested before making any of the specifics available to the public. Reports of Gericke's work and his claims that hydroponics would revolutionize plant agriculture prompted a huge number of requests for further information. Gericke had been denied use of the university's greenhouses for his experiments due to the administration's skepticism, and when the university tried to compel him to release his preliminary nutrient recipes developed at home, he requested greenhouse space and time to improve them using appropriate research facilities. While he was eventually provided greenhouse space, the university assigned Hoagland and Arnon to re-evaluate Gericke's claims and show his formula held no benefit over soil grown plant yields, a view held by Hoagland. Because of these irreconcilable conflicts, Gericke left his academic position in 1937 in a climate that was politically unfavorable and continued his research independently in his greenhouse. In 1940, Gericke, whose work is considered to be the basis for all forms of hydroponic growing, published the book, Complete Guide to Soilless Gardening. Therein, for the first time, he published his basic formulas involving the macro- and micronutrient salts for hydroponically grown plants.
== Preparation == Several preparation methods exist. Basic versions may be prepared using chopped meat, tomato, spices, and elbow macaroni. Another basic preparation method incorporates boxed, prepared macaroni and cheese and canned chili. Some recipes incorporate all of the ingredients together, while others are prepared with the ingredients separately layered. Those that use cheese may use grated cheese atop the dish, while others mix the cheese throughout the dish. Sometimes, onions or beans are added. Some diners in St. Louis, Missouri, serve a version called "chili mac a la mode", in which the dish is served topped with fried eggs. The dish may be prepared on a range top in a skillet, in a slow cooker, or baked as a casserole. Vegetarian and vegan versions of the dish are sometimes prepared.
Histology, also known as microscopic anatomy, microanatomy or histoanatomy, is the branch of biology that studies the microscopic anatomy of biological tissues. Histology is the microscopic counterpart to gross anatomy, which looks at larger structures visible without a microscope. Historically, microscopic anatomy was divided into organology, the study of organs, histology, the study of tissues, and cytology, the study of cells, although modern usage places all of these topics under the field of histology. In medicine, histopathology is the branch of histology that includes the microscopic identification and study of diseased tissue. In the field of paleontology, the term paleohistology refers to the histology of fossil organisms.
== Applications == There is almost no use for any isotope of einsteinium outside basic scientific research aiming at production of higher transuranium elements and superheavy elements. In 1955, mendelevium was synthesized by irradiating a target consisting of about 109 atoms of 253Es in the 60-inch cyclotron at Berkeley Laboratory. The resulting 253Es(α,n)256Md reaction yielded 17 atoms of the new element with the atomic number of 101. The rare isotope 254Es is favored for production of superheavy elements due to its large mass, relatively long half-life of 270 days, and availability in significant amounts of several micrograms. Hence 254Es was used as a target in the attempted synthesis of ununennium (element 119) in 1985 by bombarding it with calcium-48 ions at the superHILAC linear particle accelerator at Berkeley, California. No atoms were identified, setting an upper limit for the cross section of this reaction at 300 nanobarns.
== Charity and volunteer work == In 1994, Kermani founded a language and cultural center in his parents' hometown of Isfahan, which he ran until 1997, the year the center had to close due to deteriorating German-Iranian relations. Since fall of 2014, Kermani has been serving as a patron of the initiative Willkommen für Flüchtlinge [Welcome to Refugees] via the Ehrenamt and Flüchtlinge [Volunteering and Refugees] project run by the Kölner Freiwilligenagentur [Cologne Volunteer Agency] which coordinates its offerings with the Kölner Flüchtlingsrat [Cologne Refugee Council].
Sources: en.wikipedia.org
Vladimir Baranov is a Soviet born Canadian scientist and one of the original co-inventors of Mass cytometry technology... He co-founded DVS Sciences in 2004 (acquired by Fluidigm in 2014 and then renamed to Standard BioTools in 2022) along with Dmitry Bandura, Scott D. Tanner and Olga Ornatsky.
==== Calorimetry errors ==== The calculation of excess heat in electrochemical cells involves certain assumptions. Errors in these assumptions have been offered as non-nuclear explanations for excess heat. One assumption made by Fleischmann and Pons is that the efficiency of electrolysis is nearly 100%, meaning nearly all the electricity applied to the cell resulted in electrolysis of water, with negligible resistive heating and substantially all the electrolysis product leaving the cell unchanged. This assumption gives the amount of energy expended converting liquid D2O into gaseous D2 and O2. The efficiency of electrolysis is less than one if hydrogen and oxygen recombine to a significant extent within the calorimeter. Several researchers have described potential mechanisms by which this process could occur and thereby account for excess heat in electrolysis experiments. Another assumption is that heat loss from the calorimeter maintains the same relationship with measured temperature as found when calibrating the calorimeter. This assumption ceases to be accurate if the temperature distribution within the cell becomes significantly altered from the condition under which calibration measurements were made. This can happen, for example, if fluid circulation within the cell becomes significantly altered. Recombination of hydrogen and oxygen within the calorimeter would also alter the heat distribution and invalidate the calibration.
In the United States Code, the IEEPA is Title 50, §§1701–1707. The IEEPA authorizes the president to declare the existence of an "unusual and extraordinary threat ... to the national security, foreign policy, or economy of the United States" that originates "in whole or substantial part outside the United States." It further authorizes the president, after such a declaration, to block transactions and freeze assets to deal with the threat and requires the president to report to Congress every 6 months on the circumstances, threats and actions taken. In the event of an actual attack on the United States, the president can also confiscate property connected with a country, group, or person that aided in the attack. IEEPA falls under the provisions of the National Emergencies Act (NEA), which means that an emergency declared under the act must be renewed annually to remain in effect. The authority given to the president under the IEEPA does not grant him the ability to regulate or prohibit communication that "does not involve a transfer of anything of value", imports or exports of information or any informational materials, or transactions incidental to travel. Donations intended to relieve human suffering, such as food, clothing or medicine are also excluded unless the president specifically finds their inclusion necessary.
Morvan's syndrome (also known as Morvan's fibrillary chorea or fibrillary chorea, abbreviated as MoS) is a rare, life-threatening autoimmune disease named after the nineteenth century French physician Augustin Marie Morvan. "La chorée fibrillaire" was coined by Morvan in 1890 when describing patients with multiple, irregular contractions of the long muscles, cramping, weakness, pruritus, hyperhidrosis, insomnia and delirium. It normally presents with a slow insidious onset over months to years.. In 1890, Morvan described a patient with myokymia (muscle twitching) associated with muscle pain, excessive sweating, and disordered sleep. This rare disorder is characterized by severe insomnia, amounting to no less than complete lack of sleep (agrypnia) for weeks or months in a row, and associated with autonomic alterations consisting of profuse perspiration with characteristic skin miliaria (also known as sweat rash), tachycardia, increased body temperature, and hypertension. Patients display a remarkable hallucinatory behavior, and peculiar motor disturbances, which Morvan reported under the term “fibrillary chorea” but which are best described in modern terms as neuromyotonic discharges. The association of the disease with thymoma, tumour, autoimmune diseases, and autoantibodies suggests an autoimmune or paraneoplastic aetiology. Besides an immune-mediated etiology, it is also believed to occur in gold, mercury, or manganese poisoning.
=== Vacuum === SIMS requires a high vacuum with pressures below 10−4 Pa (roughly 10−6 mbar or torr). This is needed to ensure that secondary ions do not collide with background gases on their way to the detector (i.e., the mean free path of gas molecules within the detector must be large compared to the size of the instrument), and it also limits surface contamination by adsorption of background gas particles during measurement.
Sources: en.wikipedia.org
Reports describe effects on GABA-A receptor expression, monoamine turnover, and neurotrophic factor levels. These are proposed mechanisms drawn mainly from animal models. No single molecular target has been established.
Intranasal delivery is the route described in most published work. It is used because the peptide is degraded quickly once it reaches circulation. Direct evidence of brain penetration in humans is lacking.
Most trials are small, regionally concentrated, and often lack rigorous blinding or placebo control. Independent replication is limited. Reviews in English generally rate the evidence as preliminary.
The most common approach combines reverse-phase liquid chromatography with mass spectrometry. Chromatography separates the components while mass spectrometry confirms the molecular mass. Peptide sequencing or tandem mass analysis can further verify the amino acid order.