If you have been reading about proteolysis 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 2025-12-20. Where a claim depends on a specific study, the study is described rather than over-claimed.
Development took place at the Institute of Molecular Genetics of the Russian Academy of Sciences, where a series of short peptides were designed in the 1980s and 1990s. Selank was selected from variants of tuftsin that showed resistance to plasma peptidases. Russian regulatory approval covers it as an anxiolytic agent given intranasally. Outside that market the compound is normally handled as a research chemical rather than a medicine, and no widely recognised international pharmacopoeial monograph exists. The name Selank is a coined trade designation rather than a systematic chemical name.
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.
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.
Peptide bonds are vulnerable to protease attack, and Selank is no exception. Measured half-life in serum is short, on the order of minutes in several reports, which explains why intranasal administration is the common route described in the literature. Absorption across the nasal mucosa partially bypasses first-pass hepatic metabolism. Quantitative data on human bioavailability remain limited and are difficult to compare across studies.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Tuftsin analogue with a C-terminal Pro-Gly-Pro tail |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Abbreviated TKPRPGP in most catalogues |
| Molecular mass | About 752 Da | Value for the free peptide |
| Solubility | Freely soluble in water | Aqueous solutions are kept cold and used promptly |
| Typical storage | -20 °C, dry, protected from light | Applies to the lyophilised powder before reconstitution |
Published work on this peptide almost always uses intranasal delivery, with drops or a spray applied to the nasal mucosa. Some animal experiments have used subcutaneous or intraperitoneal injection, and a smaller number have compared routes directly. Oral administration is not a focus of the literature, because short peptides of this size are broken down by digestive enzymes and cross intestinal barriers poorly. How much of an intranasal dose reaches the bloodstream intact in humans remains an open question.
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.
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.
Many exiled Poles could not return to the country for which they had fought because they belonged to political groups incompatible with the new communist regimes, or because they originated from areas of pre-war eastern Poland that were incorporated into the Soviet Union (see Polish population transfers (1944–1946)). Some were deterred from returning simply on the strength of warnings that anyone who had served in military units in the West would be endangered. Many Poles were pursued, arrested, tortured and imprisoned by the Soviet authorities for belonging to the Home Army or other formations (see Anti-communist resistance in Poland (1944–1946)), or were persecuted because they had fought on the Western front.
Steve Ells attended the Culinary Institute of America in Hyde Park, New York. Afterward, he became a line cook for Jeremiah Tower at Stars in San Francisco. There, Ells observed the popularity of the taquerías and San Francisco burritos in the Mission District. In 1993, Ells took what he learned in San Francisco and opened the first Chipotle Mexican Grill in Denver, Colorado, in a former Dolly Madison Ice Cream store at 1644 East Evans Avenue, near the University of Denver campus, using an $85,000 loan from his father. Ells and his father calculated that the store would need to sell 107 burritos per day to be profitable. After one month, the original restaurant was selling over 1,000 burritos a day. The second store opened in 1995 using Chipotle's cash flow, and the third was opened using an SBA loan. To fund additional growth, Ells' father invested $1.5 million. Afterwards, Ells created a board of directors and business plan, raising an additional $1.8 million for the company. Ells had originally planned to use funds from the first Chipotle to open a fine-dining restaurant, but instead focused on Chipotle Mexican Grill when the restaurants saw success. In 1998, the first restaurant outside of Colorado opened in Kansas City, Missouri. In 1998, McDonald's made an initial minority investment in the company. By 2001, McDonald's had grown to be Chipotle's largest investor. The investment from McDonald's allowed the firm to quickly expand, from 16 restaurants in 1998 to over 500 by 2005.
=== Side effects === Reactogenicity is similar to that of conventional, non-RNA vaccines. However, those susceptible to an autoimmune response may have an adverse reaction to mRNA vaccines. The mRNA strands in the vaccine may elicit an unintended immune reaction – this entails the body believing itself to be sick, and the person feeling as if they are as a result. To minimize this, mRNA sequences in mRNA vaccines are designed to mimic those produced by host cells. Strong but transient reactogenic effects were reported in trials of novel COVID-19 mRNA vaccines; most people will not experience severe side effects which include fever and fatigue. Severe side effects are defined as those that prevent daily activity.
Sources: en.wikipedia.org
The first sizeable batch of Boer prisoners taken by the British consisted of those captured at the Battle of Elandslaagte on 21 October 1899. Initially, these POWs were held on troopships in Simons Bay until POW camps in Cape Town and Simonstown were completed. In total, six prisoner of war camps would be set up in South Africa. As numbers grew, the British decided they did not want them kept locally. The capture of 4000 POWs in February 1900 was a key event, which made the British realise they could not accommodate all POWs in South Africa. The British feared they could be freed by sympathetic locals. Moreover, they already had trouble supplying their troops and did not want the added burden of sending supplies for the POWs. Britain therefore sent many POWs overseas. Around 31 prisoner of war camps were consequently set up in British colonies overseas during the war. The first overseas (off African mainland) camps were opened in Saint Helena, which ultimately received about 5,000 POWs. About 5,000 POWs were sent to Ceylon. Other POWs were sent to Bermuda and India.
CTI (Capture The Intelligence) – Known in other games as Capture The Flag. Players have to pick up an object (usually a suitcase) and bring it to their designated capture area. The opposing team can shoot down the player carrying the object after which it will drop to the ground to be picked up by another player or left to respawn when it is not picked up for a certain amount of time. Once brought inside the team's capture area, the team receives reinforcements and/or point depending on the map. PS (Push) – Players have to control a series of areas (marked with flags) in a particular order to complete the map objective. On most maps, the areas are situated near both teams' spawn area and closer to the center on the map, usually counting between 3 and 5 control areas. Depending on the map, teams are rewarded with reinforcements for capturing an area which was neutral or controlled by the opposite team. Teams can also receive reinforcement penalties when the team does not control more than half of the control areas. When one team controls all the areas in the map, that team is rewarded with reinforcements and/or points. SD (Search & Destroy) – The map objective in SD maps is to destroy certain objects which are usually located near the opposing team's spawning area. Objects range from crates with ammunition and guns to trucks. Some objects can be destroyed by simply doing damage to it, while others have to be destroyed with a claymore mine. TC (Territorial Control) Teams are rewarded with points and/or reinforcements when they control certain areas.
=== Other psychoactive infusions === Ayahuasca, a South American psychoactive decoction prepared from Banisteriopsis caapi vine and a dimethyltryptamine (DMT)-containing plant, which has different legal statuses depending on jurisdiction. Cannabis tea, which contains the psychoactive THC. It is a common drink in India, where it is known as bhang. Coca tea, infusion made from coca leaves. Contains trace amounts of cocaine and similar alkaloids. In some countries where coca is illegal, products marketed as "coca tea" are supposed to be decocainized, i.e., the pharmacologically active components have been removed from the leaf using the same chemicals as manufacturing cocaine. Kava root tea, common in Pacific island cultures (Polynesia, Melanesia, Micronesia), which has sedative effects and anesthetic effects caused by compounds called kavalactones. The traditional form is a water-based suspension of kava roots. Kratom tea made from the dried leaves of the kratom tree. It has opioid-like properties and some stimulant-like effects. St. John's wort tea, the plant has been shown to have antidepressant properties according to a 2017 meta-analysis. Ephedra tea, mainly from the plant Ephedra sinica. It contains the stimulant ephedrine. It has been used in traditional Chinese medicine, where it is called máhuáng, for more than 2,000 years. Ephedra tea was also used by Native Americans and Mormons, hence the name "Mormon tea" and "Indian tea". Poppy tea, brewed from the poppy straw or seeds of several species of poppy (most commonly Papaver somniferum).
Sources: en.wikipedia.org
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.
Tuftsin is a natural tetrapeptide derived from the Fc portion of immunoglobulin G. Selank retains that tetrapeptide at its N-terminus and adds three residues to improve resistance to enzymatic breakdown. The relationship is structural, and the two molecules are not interchangeable in experimental work.
It holds a product registration in Russia for intranasal use as an anxiolytic. Registrations of that kind are not automatically accepted by regulators elsewhere. In most other countries it is treated as an unapproved substance or a research material.
Dry powder is best kept sealed, protected from light, and held at minus 20 degrees Celsius or below. Desiccant packaging helps limit moisture uptake because the material is hygroscopic. A sealed vial should be allowed to equilibrate to room temperature before opening to reduce condensation.