This is a working overview of tuftsin, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-07-13 and is reviewed periodically as new material appears.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Modeled on tuftsin |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Seven residues |
| Approximate molecular mass | Around 750 Da | Depends on counter-ion and hydration |
| Common forms | Lyophilized powder | Also described as aqueous solution |
| Primary origin of research | Russian laboratories | Mid-1990s onward |
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.
Handling follows standard practice for research peptides. Material is weighed in a low-humidity environment because the powder absorbs atmospheric moisture. Purity is reported as the percentage area of the main peak in a chromatogram, with specifications commonly set at 95 percent or higher; values below that threshold indicate the presence of truncated or modified species. Residual trifluoroacetate from purification is often present and may affect mass balance. Certificates of analysis should state the analytical method, the column and gradient used, and the lot-specific retention time so that results can be compared across suppliers.
Identity and purity of selank are established with reversed-phase high-performance liquid chromatography coupled to mass spectrometry. The peptide elutes from C18 columns with acetonitrile gradients in water containing trifluoroacetic acid or formic acid, and detection is usually performed by ultraviolet absorbance near 214 nm. Electrospray ionization in positive mode gives a doubly protonated ion near m/z 377, consistent with a mass of about 752 Da. Amino acid analysis or tandem mass spectrometry of fragment ions confirms the sequence. Because the molecule has no aromatic residues, it lacks a usable 280 nm chromophore, so low-wavelength detection or mass spectrometry is required.
== Nomenclature == Arrhenius acids are named according to their anions. In the classical naming system, the ionic suffix is dropped and replaced with a new suffix, according to the table following. The prefix "hydro-" is used when the acid is made up of just hydrogen and one other element. For example, HCl has chloride as its anion, so the hydro- prefix is used, and the -ide suffix makes the name take the form hydrochloric acid. Classical naming system:
=== Discoveries in chemistry === By the 18th century the principle of conservation of mass during chemical reactions was widely used and was an important assumption during experiments, even before a definition was widely established, though an expression of the law can be dated back to Hero of Alexandria's time, as can be seen in the works of Joseph Black, Henry Cavendish, and Jean Rey. One of the first to outline the principle was Mikhail Lomonosov in 1756. He may have demonstrated it by experiments and certainly had discussed the principle in 1748 in correspondence with Leonhard Euler, though his claim on the subject is sometimes challenged. According to the Soviet physicist Yakov Dorfman:The universal law was formulated by Lomonosov on the basis of general philosophical materialistic considerations, it was never questioned or tested by him, but on the contrary, served him as a solid starting position in all research throughout his life. A more refined series of experiments were later carried out by Antoine Lavoisier who expressed his conclusion in 1773 and popularized the principle of conservation of mass. The demonstrations of the principle disproved the then popular phlogiston theory that said that mass could be gained or lost in combustion and heat processes. The conservation of mass was obscure for millennia because of the buoyancy effect of the Earth's atmosphere on the weight of gases. For example, a piece of wood weighs less after burning; this seemed to suggest that some of its mass disappears, or is transformed or lost.
Interbake Foods of Richmond, Virginia, produces most of the commercially available hardtack in the United States, under the "Sailor Boy" label. As of January 2015, 98 percent of its production goes to Alaska. Alaskans are among the last to still eat hardtack as a significant part of their normal diet. Originally imported as a food product that could endure the rigors of transportation throughout Alaska, hardtack has remained a favored food even as other, less robust foods have become more readily available. Alaskan law requires all light aircraft to carry "survival gear", including food. Therefore, the blue-and-white Sailor Boy Pilot Bread boxes are ubiquitous at Alaskan airstrips, in cabins, and in virtually every village. Unlike the traditional hardtack recipe, Sailor Boy Pilot Bread contains leavening and vegetable shortening. Hardtack is also a common pantry item in Hawaii, and The Diamond Bakery's "Saloon Pilot" cracker is available there in grocery and convenience stores. The round hardtack crackers are available in large- and small-diameter sizes. Those who buy commercially baked hardtack in the contiguous US are often those who stock up on long-lasting foods for disaster survival rations, though these usually take the form of food ration bars or freeze dried meals rather than traditional hardtack. Many other people who currently buy or bake hardtack in the US are Civil War re-enactors. The 3rd US Regular Infantry Reenactors, for example, often cook many recipes during their reenacting camps, to include hardtack.
== Progress and status == The project has genetically engineered microorganisms to produce long-acting (glargine) and short-acting (lispro) insulin analogs using standard techniques in biotechnology and according to their December 2018 release the "first major milestone ― the production of insulin at lab scale ― is almost complete". The cost to produce insulin via Open Insulin methods is estimated by the project to be such that "roughly $10,000 should be enough to get a group started with the equipment needed to produce enough insulin for 10,000 people". A more recent estimate (May 2020) by the Open Insulin Foundation states that it will cost $200,000 (one-time price, per patient of $7-$20) for used equipment and up to $1,000,000 (one-time price, per patient of $73) for new equipment. The average price per vial was estimated to be $7 with each patient needing two vials per month.
Sources: en.wikipedia.org
Unlike translucent nanoemulsions, which require specialized equipment to be produced, microemulsions are spontaneously formed by "solubilizing" oil molecules with a mixture of surfactants, co-surfactants, and co-solvents. The required surfactant concentration in a microemulsion is, however, several times higher than that in a translucent nanoemulsion, and significantly exceeds the concentration of the dispersed phase. Because of many undesirable side-effects caused by surfactants, their presence is disadvantageous or prohibitive in many applications. In addition, the stability of a microemulsion is often easily compromised by dilution, by heating, or by changing pH levels. Common emulsions are inherently unstable and, thus, do not tend to form spontaneously. Energy input – through shaking, stirring, homogenizing, or exposure to powerful ultrasound – is needed to form an emulsion. Over time, emulsions tend to revert to the stable state of the phases comprising the emulsion. An example of this is seen in the separation of the oil and vinegar components of vinaigrette, an unstable emulsion that will quickly separate unless shaken almost continuously. There are important exceptions to this rule – microemulsions are thermodynamically stable, while translucent nanoemulsions are kinetically stable. Whether an emulsion of oil and water turns into a "water-in-oil" emulsion or an "oil-in-water" emulsion depends on the volume fraction of both phases and the type of emulsifier (surfactant) (see Emulsifier, below) present.
The diarrheal type is associated with a wide range of foods, has an 8-to-16-hour incubation time, and is associated with diarrhea and gastrointestinal pain. Also known as the 'long-incubation' form of B. cereus food poisoning, it might be difficult to differentiate from poisoning caused by Clostridium perfringens. Enterotoxin can be inactivated after heating at 56 °C (133 °F) for 5 minutes, but whether its presence in food causes the symptom is unclear, since it degrades in stomach enzymes; its subsequent production by surviving B. cereus spores within the small intestine may be the cause of illness. The 'emetic' form commonly results from rice which is cooked at a time and temperature insufficient to kill any spores present, then improperly refrigerated. The remaining spores can produce a toxin, cereulide, which is not inactivated by later reheating. This form leads to nausea and vomiting 1–5 hours after consumption. Distinguishing from other short-term bacterial foodborne intoxications, such as by Staphylococcus aureus, can be difficult. Emetic toxin can withstand 121 °C (250 °F) for 90 minutes. As a result of the emetic type's association with rice, it is sometimes referred to colloquially as fried rice syndrome. The diarrhetic syndromes observed in patients are thought to stem from the three toxins: hemolysin BL (Hbl), nonhemolytic enterotoxin (Nhe), and cytotoxin K (CytK). The nhe/hbl/cytK genes are located on the chromosome of the bacteria. Transcription of these genes is controlled by PlcR. These genes occur in the taxonomically related B. thuringiensis and B.
All At Once, which will document Collins alongside her family as she embarks on IVF treatment and plans her wedding following her engagement to Rami Hawash. On the commissioning of the show, Collins described the upcoming year as the "most important in her life", and said that "for the first time [in the series] people will get to see the Gemma behind the GC." [...] Collins added that she felt "ready to truly open up, not just about the present, but about [her] past and everything [she'd] been through to become the woman [she is] today.
=== Collagen fibers === Type I collagen comprises approximately 85-95% of the organic matrix, providing the structural scaffold and tensile strength necessary for bone formation. These collagen fibers form a dense, highly cross-linked network that serves as the foundation for subsequent mineralization. The collagen molecules are arranged in layers that alternate parallel and orthogonal to the axis of stress loading, creating a sophisticated composite structure.
A breeder reactor is a nuclear reactor that generates more fissile material than it consumes. These reactors can be fueled with more-commonly available isotopes of uranium and thorium, such as uranium-238 and thorium-232, as opposed to the rare uranium-235 which is used in conventional reactors. These materials are called fertile materials since they can be bred into fuel by these breeder reactors. Breeder reactors achieve this because their neutron economy is high enough to create more fissile fuel than they use. These extra neutrons are absorbed by the fertile material that is loaded into the reactor along with fissile fuel. This irradiated fertile material in turn transmutes into fissile material which can undergo fission reactions. Breeders were at first found attractive because they made more complete use of uranium fuel than light-water reactors, but interest declined after the 1960s as more uranium reserves were found and new methods of uranium enrichment reduced fuel costs. Breeder reactors have been developed and operated in Russia, India, Japan, the United States, France, and China, but only Russia is currently operating a commercial fast breeder reactor as of April 2026.
Sources: en.wikipedia.org
Selank is a synthetic peptide made of seven amino acids. It is modeled on tuftsin, a natural tetrapeptide, with an added three-residue tail. It is not a small-molecule drug.
It originates from research in Russia, associated with the Institute of Molecular Genetics of the Russian Academy of Sciences. The first descriptions date to the mid-1990s. Most published studies come from Russian laboratories.
No, Selank itself does not occur naturally. Its backbone is based on tuftsin, which is produced in the body, but the seven-residue version is a synthetic construct. It is supplied as a manufactured peptide.
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.