If you have been reading about Pro-Gly-Pro 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 2025-08-21. Where a claim depends on a specific study, the study is described rather than over-claimed.
Animal studies have examined behaviour in tests of anxiety, memory retention and stress response, and several report changes in neurotrophic or neurotransmitter-related markers. The human evidence base is much smaller, consisting mainly of short trials conducted in Russia with limited reporting in English-language journals. Sample sizes are modest and outcome measures vary between studies, so the findings are best described as preliminary. Independent replication under modern trial standards has not been widely reported.
Outside its country of origin the compound is generally handled as a research chemical rather than an approved medicine. No regulatory approval from the United States Food and Drug Administration or the European Medicines Agency has been granted for human use. Identity and purity are normally checked by reverse-phase high-performance liquid chromatography, with mass spectrometry used to confirm the molecular mass. Lyophilised material is stored cold and desiccated, and repeated freeze-thaw cycles are avoided.
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.
| Property | Value | Notes |
|---|---|---|
| Common route | Intranasal | Also injected in some animal work |
| Solubility class | Freely soluble in water | Solid form is hygroscopic |
| Typical storage | About -20 degrees Celsius | Keep desiccated and dark |
| Purity method | Reverse-phase HPLC | Reported as area percent |
| Confirmatory method | Mass spectrometry | Verifies expected molecular mass |
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.
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.
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.
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.
=== Entrepreneurship and biotechnology investing === Springer co-founded biotechnology companies Scholar Rock in 2012, Morphic Therapeutic in 2015, Tectonic Therapeutic in 2019, and Seismic Therapeutic in 2022. He was also an early investor in Selecta Biosciences and Editas Medicine. Springer was a founding investor of Moderna after investing USD$5 million in 2010. He was the company's fourth-largest shareholder and made USD$400 million when the company launched its initial public offering (IPO) in 2018. During the COVID-19 pandemic, Forbes estimated Springer's net worth as USD$1 billion after in share price of biotechnology companies surged.
RGD and other bioactive ligands can be presented on the surface of a biomaterial in a number of different spatial arrangements, and it has been demonstrated that these arrangements have a significant impact on cell behavior. In self-assembled monolayers, it was found that adhesion and proliferation of both human umbilical vein endothelial cells (HUVECs) and human mesenchymal stem cells (MSCs) increased as a function of RGD peptide density. These studies also showed that RGD density could change integrin expression, which has been postulated to enable control of biochemical signaling pathways. Further investigation of MSCs on self-assembled monolayers showed that modulating RGD density and the affinity of RGD for αvβ3 (through use of linear and cyclized RGD) could be used to control the differentiation of MSCs. The effect of RGD presentation on cells in 3D biomaterials, which more accurately replicate the in vivo environment, has also been evaluated. In degradable polyethylene glycol hydrogels, the length of capillary-like structures formed by HUVECs was directly proportional to the density of RGD in the hydrogel. Additionally, studies in nano-patterning have shown that, whereas an increase in global RGD density increases cell adhesion strength until saturation, an increase in local (mico/nano-scale) RGD density does not follow this trend.
US Health Physics Society United Nations "Human rights and weapons of mass destruction, or with indiscriminate effect, or of a nature to cause superfluous injury or unnecessary suffering" (The UN 2002 report) Depleted Uranium and the IAEA Scientific reports ATSDR – Case Studies in Environmental Medicine (CSEM): Uranium Toxicity Archived 4 February 2016 at the Wayback Machine U.S. Department of Health and Human Services "Depleted Uranium in Bosnia and Herzegovina – Postconflict Assessment" Archived 25 February 2012 at the Wayback Machine by UN Environment Programme "Radiological Conditions in Areas of Kuwait With Residues of Depleted Uranium" by International Atomic Energy Agency "Technical Report on Capacity-building for the Assessment of Depleted Uranium in Iraq" Archived 9 March 2012 at the Wayback Machine by UN Environment Programme "A Review of the Scientific Literature As It Pertains to Gulf War Illnesses" by RAND Depleted Uranium article from the Royal Society (archived) An Analysis of Uranium Dispersal and Health Effects Using a Gulf War Case Study by Sandia National Laboratories Depleted Uranium Human Health Fact Sheet by Argonne National Laboratory Environmental Assessment Division Depleted uranium (DU) normative value pilot study: levels of uranium in urine samples from the general population Archived 26 July 2011 at the Wayback Machine by A.D. Jones, B. G. Miller, S. Walker, J. Anderson, A. P. Colvin, P.A. Hutchison, C.A. Soutar.
=== Litra symbol === The Roman libra and Byzantine lítra (λίτρα), which served as both the pound mass unit and liter volume unit, were abbreviated in Greek using lambda with modified forms of the iota subscript ⟨λͅ⟩. These are variously encoded in Unicode. The Ancient Greek Numbers Unicode block includes 10183 greek litra sign (𐆃) as well as 𐅢, which is described as 10162 greek acrophonic hermionian ten but was much more common as a form of the litra sign. A variant of the sign can be formed from 0338 combining long solidus overlay and either 039B greek capital letter lamda (Λ̸) or 03BB greek small letter lamda (λ̸).
Milanese resumed football activity only at a regional level, only to officially end it at the end of the 1945-1946 season. In 2021, after 75 years, a new project is initiated: from the union of three clubs from the south of Milan (Accademia Sandonatese and ACD Metanopoli Calcio) Football Club Milanese 1902 is born, whose first team plays in the fifth division of the Italian championship, with a regional youth sector. F.C. Milanese 1902 was recreated with the intention of giving continuity in the football field to its ancestor U.S. Milanese, taking up its history, logo, traditions and club colours. Right now, F.C. Milanese 1902 is playing at the non-professional level with a youth sector of regional level.
Sources: en.wikipedia.org
=== Machine guns === Vickers machine gun – Not declared obsolete until 1968. Bren light machine gun – Original .303 versions used in early stages of the Cold War, L4A1-A6 7.62mm NATO variants in service from 1955 onwards. M1919 Browning machine gun - Mounted on vehicles and ground tripods L7A1/A2 GPMG - Adopted in 1958. Primary infantry machine gun until the 1980s, when it was replaced in infantry sections by the L86A1 listed below (though it remained in use with support company machine gun platoons). Also mounted on various vehicles. L86A1 Light Support Weapon - Initial batches issued in 1985; frontline Army units, Royal Marines, and RAF Regiment scheduled to be fully equipped by 1987, rest of regular Army scheduled to be fully equipped by 1990.
The two substrates of this enzyme are 3-nitropropionic acid and oxidised nicotinamide adenine dinucleotide phosphate (NADP+). Its products are 3-nitroacrylic acid, reduced NADPH, and a proton. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-CH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is 3-nitropropanoate:NADP+ oxidoreductase.
In Canada and the United States, half and half almost always refers to a light cream typically used in coffee. (See above.) The name refers to the liquid's content of half milk and half cream. It is widely available in the United States, both in individual-serving containers and in bulk. It is also used to make ice cream. Non-fat versions of the product are also available, containing corn syrup and other ingredients. This half and half can be also used to make a dirty soda. In addition to the light coffee cream, half and half can refer to other drinks in some regions of the U.S. A half and half of iced tea and lemonade is popular in the Northeastern United States. It consists of one part iced tea, sweetened, unsweetened or both, and one part lemonade served over ice. This drink is also called an Arnold Palmer, named for an American golfer, but that drink more correctly is mostly tea with one-quarter to one-third lemonade. In the Southern United States (specifically the cities of Atlanta and Houston), "half and half" may also refer to a mixture of half sweet and half unsweetened iced tea. Some coffee shops in colder climates serve a half and half drink consisting of half coffee and half hot chocolate, similar to caffè mocha. Half and half might also refer to a flavor of soda that combines the flavors of grapefruit and lemon.
Due to its risks, the use of flutamide in cisgender and transgender women is now limited and discouraged. Flutamide and nilutamide have largely been superseded by bicalutamide in clinical practice, with bicalutamide accounting for almost 90% of nonsteroidal antiandrogen prescriptions in the United States by the mid-2000s. Bicalutamide is said to have excellent tolerability and safety relative to flutamide and nilutamide, as well as in comparison to cyproterone acetate. It has few to no side effects in women. Despite its greatly improved tolerability and safety profile however, bicalutamide does still have a small risk of elevated liver enzymes and association with rare cases of serious liver damage and lung disease. Nonsteroidal antiandrogens like bicalutamide may be a particularly favorable option for transgender women who wish to preserve sex drive, sexual function, and/or fertility, relative to antiandrogens that suppress testosterone levels and can greatly disrupt these functions such as cyproterone acetate and GnRH modulators. However, estrogens suppress testosterone levels and at high doses can markedly disrupt sex drive and function and fertility on their own. Moreover, disruption of gonadal function and fertility by estrogens may be permanent after extended exposure.
Wells refused the offered freedom of the town, stating: "Bromley has not been particularly gracious to me nor I to Bromley and I don't think I want to add the freedom of Bromley to the freedom of the City of London and the freedom of the City of Brussels – both of which I have." He described Bromley in one of his novels as a "morbid sprawl of population".
Sources: en.wikipedia.org
=== Ethanol === The first historical achievement in anesthesia occurred around 4000 BC in ancient Mesopotamia. This was the advent of ethanol (commonly known as drinking alcohol), the first general anaesthetic agent. These accounts of the anesthetic uses of ethanol come from the oldest known historical civilization of Sumer and are documented in the oldest known writing system cuneiform.
Pancreatic secretory trypsin inhibitor (PSTI) also known as serine protease inhibitor Kazal-type 1 (SPINK1) or tumor-associated trypsin inhibitor (TATI) is a protein that in humans is encoded by the SPINK1 gene. In the context of rat biology, it is also sometimes called monitor peptide.
The need for an international standard for chemistry was first addressed in 1860 by a committee headed by German scientist Friedrich August Kekulé von Stradonitz. This committee was the first international conference to create an international naming system for organic compounds. The ideas that were formulated at that conference evolved into the official IUPAC nomenclature of organic chemistry. IUPAC is a legacy of this meeting, making it one of the most important historical international collaborations of chemistry societies. IUPAC as such was established in 1919.Since this time, IUPAC has been the official organization with the responsibility of updating and maintaining official organic nomenclature. One notable country excluded from early IUPAC was Germany. Germany's exclusion was a result of prejudice towards it by the Allied powers after World War I. Germany was finally admitted into IUPAC in 1929. However, Nazi Germany was removed from IUPAC during World War II. At this time, IUPAC was affiliated with the Allied powers, but had little involvement with the war effort itself. East and West Germany were only readmitted to IUPAC in 1973. Since World War II, IUPAC has focused on standardizing nomenclature and methods in science. In 2016, IUPAC denounced the use of chlorine as a chemical weapon. In a letter to Ahmet Üzümcü, director of the Organisation for the Prohibition of Chemical Weapons (OPCW), the organization pointed out their concerns in regards to chlorine weapon usage in the Syrian civil war and other places .
The Pantheon of Skeptics was created by CSI to remember the legacy of deceased fellows of CSI and their contributions to the cause of scientific scepticism. A sculpted bust of Francis Crick by John Sherrill Houser, which incorporates a single "Golden" Helix, was cast in bronze in the artist's studio in New Mexico, US. The bronze was first displayed at the Francis Crick Memorial Conference (on Consciousness) at Churchill College, Cambridge on 7 July 2012; it was bought by Mill Hill School in May 2013, and displayed at the inaugural Crick Dinner on 8 June 2013, and was again at their Crick Centenary Dinner in 2016. The Benjamin Franklin Medal for Distinguished Achievement in the Sciences of the American Philosophical Society (2001), together with Watson. Crick featured in the BBC Radio 4 series The New Elizabethans to mark the Diamond Jubilee of Elizabeth II in 2012. A panel of seven academics, journalists and historians named Crick among a group of 60 people in the UK "whose actions during the reign of Elizabeth II have had a significant impact on lives in these islands and given the age its character".
== Role in hair growth/loss == In February 2008, researchers at the University of Bonn announced they have found the genetic basis of two distinct forms of inherited hair loss, opening a broad path to treatments for baldness. They found that mutations in the gene P2RY5 causes a rare, inherited form of hair loss called hypotrichosis simplex. It is the first receptor in humans known to play a role in hair growth. The fact that any receptor plays a specific role in hair growth was previously unknown to scientists, and with this new knowledge a focus on finding more of these genes may be able to lead to therapies for many different types of hair loss. In 2013, it was found that mutations in LPAR6 give rise to the Cornish Rex cat breed, which has a form of ectodermal dysplasia characterised by short woolly hair which is susceptible to loss.
Sources: en.wikipedia.org
Most published work uses intranasal application, either as drops or as a nasal spray. Injection routes appear in a smaller set of animal experiments. Oral use is uncommon in the literature because peptide breakdown and poor absorption limit this route.
Reported human trials are few, brief and originate mainly from one country. They describe effects on anxiety-related measures, but sample sizes are small and reporting is limited. The results are widely regarded as preliminary rather than confirmed.
Reverse-phase liquid chromatography is used to assess purity and separation of related impurities. Mass spectrometry confirms that the observed molecular mass matches the expected peptide. A certificate of analysis from the supplier is the usual document of record.
Selank is a seven-amino-acid peptide built from the tuftsin sequence plus a Pro-Gly-Pro tail. It is produced by chemical synthesis rather than extracted from a natural source. The free peptide is usually supplied as a lyophilised powder or in an aqueous formulation.