Everything below concerns Pro-Gly-Pro. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-05-09. Numbers and descriptions here follow the published literature rather than marketing material.
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.
The compound was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences during the 1980s and 1990s. The stated design goal was to retain the immunomodulatory and central nervous system activity attributed to tuftsin while improving resistance to enzymatic breakdown. Adding a proline-rich tail to the short parent peptide was a deliberate strategy, because proline residues restrict the conformations available to many peptidases. The same laboratory produced Semax, an ACTH fragment analog, and both compounds were developed in parallel as short, enzymatically stabilized peptides intended for intranasal use.
Selank is not a naturally occurring peptide and has no known endogenous counterpart in human physiology. Russian-language sources frequently call it TP-7, while English-language sources use the name Selank almost exclusively. Database indexing is uneven, partly because early reports appeared in regional journals that are not widely cataloged. Some summaries describe the material as a tuftsin analog and others as a synthetic heptapeptide; the labels overlap rather than conflict. Citing the primary sequence resolves ambiguity more reliably than the research or trade name alone.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter notation. Its structure consists of the immunomodulatory tetrapeptide tuftsin, Thr-Lys-Pro-Arg, extended at the carboxyl terminus by a Pro-Gly-Pro segment. The molecular formula is commonly given as C33H57N11O9, corresponding to a monoisotopic mass near 751.4 Da and an average molecular mass near 751.9 Da. All seven residues are proteinogenic amino acids, and the molecule carries no modified side chains or non-natural linkages.
| 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 |
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.
Purity assessment relies mainly on reverse-phase high-performance liquid chromatography with ultraviolet detection. Because the peptide lacks a strong chromophore, detection often uses backbone absorbance near 214 nm. Identity is confirmed by mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, comparing the measured mass against the expected value. Amino acid analysis can verify composition after acid hydrolysis. Diastereomer content and residual counterions are reported less often, although both can influence biological assays.
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.
Laboratory work relies on standard behavioral paradigms. Rodents are tested in the elevated plus maze, open field, and passive avoidance tasks, with outcomes compared against diazepam or vehicle controls. Intranasal dosing is used most often because it bypasses first-pass metabolism, though intraperitoneal and intravenous routes also appear in published protocols. Biochemical endpoints include tissue BDNF concentrations, cytokine levels, and monoamine metabolites. Human data are limited to small Russian trials reporting reduced anxiety scores; most were not prospectively registered, and few employed independent outcome assessment.
Measuring peptide exposure inside the brain is technically difficult. Selank is degraded rapidly in plasma, and assays must separate intact peptide from fragments, which favors targeted mass spectrometry over immunoassays alone. Reported half-lives are short, on the order of minutes, so effects observed hours later are attributed to downstream signaling rather than to the parent compound. Blood-brain barrier permeability is debated and rarely quantified directly. Gaps include absent dose-response characterization, inconsistent reporting of purity, and almost no pharmacokinetic data from human participants.
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.
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.
=== Eddy viscosity === In the study of turbulence in fluids, a common practical strategy is to ignore the small-scale vortices (or eddies) in the motion and to calculate a large-scale motion with an effective viscosity, called the "eddy viscosity", which characterizes the transport and dissipation of energy in the smaller-scale flow (see large eddy simulation). In contrast to the viscosity of the fluid itself, which must be positive by the second law of thermodynamics, the eddy viscosity can be negative.
Javits (1952), former ambassador and permanent U.S. representative to the Conference on Disarmament in Geneva 2001–2003; U.S. permanent representative to the Organisation for the Prohibition of Chemical Weapons 2003–2009 James D. Theberge (1952), former U.S. ambassador to Chile and Nicaragua G. Norman Anderson (1954), former U.S. ambassador to Sudan David J. Bardin (1954), deputy administrator of the Federal Energy Administration; commissioner of the New Jersey Department of Environmental Protection William Haddad (1954), political operative, lobbyist, and journalist, Peace Corps founding official, aide to the Kennedy family, and grandson-in-law of Franklin D. Roosevelt Richard E. Benedick (1955), president emeritus of the National Council for Science and the Environment, ambassador, and chief U.S. negotiator to the Montreal Protocol John L. Hirsch (1957), U.S. ambassador to Sierra Leone 1995–1998 Morton Halperin (1958), deputy assistant secretary of defense, director of policy planning for the U.S. State Department, and member of Richard Nixon's Enemies List Shelby Brewer (1959), assistant secretary of energy for nuclear energy 1981–1984 Benjamin Huberman (1959), acting director of the Office of Science and Technology Policy; acting science advisor to the president in 1981 Pat Mullins (1959), chairman of the Republican Party of Virginia Constantine Menges (1960), national security aide to Ronald Reagan James E.
The larynx is a major (but not the only) source of sound in speech, generating sound through the rhythmic opening and closing of the vocal folds. To oscillate, the vocal folds are brought near enough together such that air pressure builds up beneath the larynx. The folds are pushed apart by this increased subglottal pressure, with the inferior part of each fold leading the superior part. Such a wave-like motion causes a transfer of energy from the airflow to the fold tissues. Under the correct conditions, the energy transferred to the tissues is large enough to overcome losses by dissipation and the oscillation pattern will sustain itself. In essence, sound is generated in the larynx by chopping up a steady flow of air into little puffs of sound waves. The perceived pitch of a person's voice is determined by a number of different factors, most importantly the fundamental frequency of the sound generated by the larynx. The fundamental frequency is influenced by the length, size, and tension of the vocal folds. This frequency averages about 125 Hz in an adult male, 210 Hz in adult females, and over 300 Hz in children. Depth kymography is an imaging method to visualize the complex horizontal and vertical movements of vocal folds. The vocal folds generate a sound rich in harmonics. The harmonics are produced by collisions of the vocal folds with themselves, by recirculation of some of the air back through the trachea, or both.
=== Effects === Bradykinin is a potent endothelium-dependent vasodilator and mild diuretic, which may cause a lowering of the blood pressure. It also causes contraction of non-vascular smooth muscle in the bronchus and gut, increases vascular permeability and is also involved in the mechanism of pain. During inflammation, it is released locally from mast cells and basophils during tissue damage. Specifically in relation to pain, bradykinin has been shown to sensitize TRPV1 receptors, thus lowering the temperature threshold at which they activate, thus presumably contributing to allodynia. Initial secretion of bradykinin post-natally causes constriction and eventual atrophy of the ductus arteriosus, forming the ligamentum arteriosum between the pulmonary trunk and aortic arch. It also plays a role in the constriction and eventual occlusion of a number of other fetal vessels, including the umbilical arteries and vein. The differential vasoconstriction of these fetal vessels compared to the vasodilator response of other vessels suggests that the walls of these fetal vessels are different from other vessels.
Sources: en.wikipedia.org
== Behavior and diet == It is a secretive species and is seldom encountered by humans. It is active by day and night, though it is usually more active by day. This largely aquatic snake spends most of its time in the water. It is an excellent swimmer and is capable of remaining underwater for up to 10 minutes and diving to depths of 25 m (82 ft). It is a slow mover on land, and it tends to hide among rocks, in holes, or overhanging tree roots at the shoreline. It also makes use of any man-made structures, such as bridges and jetties, to hide. It is generally not aggressive, and if approached in water, it will swim away swiftly and on land will attempt to escape into water. If threatened on land, it will rear up and spread its narrow, yet prominent hood and it may hiss loudly, but it tends not to make any forward movements. It will only bite when provoked. It preys almost exclusively on fish. It may also prey on frogs, toads, and other amphibians.
On July 16, 1945, the first atomic bomb test took place near the town of Alamogordo (New Mexico, USA). As a result of the atmospheric nuclear weapons tests carried out by the United States, the Soviet Union, France, Great Britain, and China, the Earth's atmosphere became increasingly contaminated with fission products from these tests from the 1950s onwards. The radioactive fallout landed on the earth's surface and ended up in plants and, via animal feed, in food of animal origin. Ultimately, they entered the human body and could be detected in bones and teeth as strontium-90, among other things. The radioactivity in the field was measured with a gamma scope, as shown at the air raid equipment exhibition in Bad Godesberg in 1954. Around 180 tests were carried out in 1962 alone. The extent of the radioactive contamination of the food sparked worldwide protests in the early 1960s.
are also called clumped-isotope temperatures. When a Δ value is smaller than zero, there is no inferred equilibration temperature associated with it. Because at any finite temperature, the equilibrium Δ value is always positive.
=== MSEIRS model === An MSEIRS model is similar to the MSEIR, but the immunity in the R class would be temporary, so that individuals would regain their susceptibility when the temporary immunity ended.
== Education == Goodacre studied the Natural Sciences Tripos at the University of Cambridge as a student of Gonville and Caius College, Cambridge, graduating in 1995. Goodacre joined the University of Nottingham for her graduate studies and earned her PhD in 1999 for studies on the evolution of Partula land snails.
Sources: en.wikipedia.org
=== Climate change === Panera Bread includes a "Cool Food" pledge in its campaign to "curb global warming". Panera Bread provides American consumers with dietary guidelines to help them change their eating patterns to help reduce carbon emissions. Through the Cool Foods pledge, the company uses traffic lights for different healthy and unhealthy foods. Foods labeled "green" are branded healthy, while those labeled "yellow" are warned to be consumed in moderation. In 2015, Panera Bread also announced its policy against the use of genetically modified organisms (GMOs), making it the first food chain in the country to question the safety and environmental friendliness of these foods.
=== Human monoclonal antibodies === Human monoclonal antibodies (suffix -umab) are produced using transgenic mice or phage display libraries by transferring human immunoglobulin genes into the murine genome and vaccinating the transgenic mouse against the desired antigen, leading to the production of appropriate monoclonal antibodies. Murine antibodies in vitro are thereby transformed into fully human antibodies. The heavy and light chains of human IgG proteins are expressed in structural polymorphic (allotypic) forms. Human IgG allotype is one of the many factors that can contribute to immunogenicity.
== Glucocorticoids == Glucocorticoids are a class of corticosteroids that affect the metabolism of carbohydrates, fat, and proteins, and regulate glycogen and blood pressure levels. They possess pronounced anti-inflammatory activity and cause alteration of connective tissue in response to injuries. The anti-inflammatory and connective tissue effects of glucocorticoids might mask injuries, leading to more serious injuries to athletes. Because of this and metabolic regulation effects, the administration of any glucocorticoid orally, rectally, intravenously, or intramuscularly is prohibited in competition only and requires a therapeutic use exemption. Topical uses of glucocorticoids does not require an exemption.
=== Independent Namibia === When Namibia gained its independence in 1990, SWAPO became the dominant political party. Though the organisation rejected the term South West Africa and preferred to use Namibia, the organisation's original name—derived from the territory's old name—was too deeply rooted in the independence movement to be changed. However, the original full name is no longer used; only the acronym remains. SWAPO, and with it much of Namibia's government and administration, continues to be dominated by the Ovambo ethnic group, despite "considerable efforts to counter [that] perception". SWAPO president Sam Nujoma was declared Namibia's first President after SWAPO won the inaugural election in 1989. A decade later, Nujoma had the constitution changed so he could run for a third term in 1999, as it limits the presidency to two terms. In 2004, the SWAPO presidential candidate was Hifikepunye Pohamba, described as Nujoma's hand-picked successor. In 2014, the SWAPO presidential candidate was Hage Geingob, who was the vice-president of SWAPO. In 2019 presidential election, president Geingob won his second five-year term as Namibian president.
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 sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter code. It combines the tetrapeptide tuftsin with a carboxyl-terminal Pro-Gly-Pro extension. This full sequence identifies the molecule more precisely than the research name.