Research chemical comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Last reviewed on 2026-06-25. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
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.
| 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 |
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.
Peptide bonds in selank are susceptible to hydrolysis under strongly acidic or basic conditions, and the terminal proline residues are vulnerable to exopeptidase activity in biological samples. Lyophilized powder stored dry at -20 °C typically remains stable for extended periods, whereas aqueous solutions degrade faster and may lose measurable purity within days to weeks depending on pH, temperature, and microbial load. Repeated freeze-thaw cycles promote aggregation and adsorption to container surfaces. For analytical work, solutions are usually prepared fresh, kept cold, and used within a single working day.
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.
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.
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.
Angelopoulos was awarded honorary doctorates by the Université libre de Bruxelles, Belgium in 1995, by Paris West University Nanterre La Défense, France, by the University of Essex, UK in July 2001, by the University of Western Macedonia, Greece in December 2008, and by the University of the Aegean, Greece in December 2009.
Mutarotation consists of a temporary reversal of the ring-forming reaction, resulting in the open-chain form, followed by a reforming of the ring. The ring closure step may use a different −OH group than the one recreated by the opening step (thus switching between pyranose and furanose forms), or the new hemiacetal group created on C-1 may have the same or opposite handedness as the original one (thus switching between the α and β forms). Thus, though the open-chain form is barely detectable in solution, it is an essential component of the equilibrium. The open-chain form is thermodynamically unstable, and it spontaneously isomerizes to the cyclic forms. (Although the ring closure reaction could in theory create four- or three-atom rings, these would be highly strained, and are not observed in practice.) In solutions at room temperature, the four cyclic isomers interconvert over a time scale of hours, in a process called mutarotation. Starting from any proportions, the mixture converges to a stable ratio of α:β 36:64. The ratio would be α:β 11:89 if it were not for the influence of the anomeric effect. Mutarotation is considerably slower at temperatures close to 0 °C (32 °F).
Apart from diagnosing hyperprolactinemia and hypopituitarism, prolactin levels are often checked by physicians in those who have had a seizure, when there is a need to differentiate between epileptic seizure or a non-epileptic seizure. Shortly after epileptic seizures, prolactin levels often rise, whereas they are normal in non-epileptic seizures.
The Portuguese Republican Party (Portuguese: Partido Republicano Português, pronounced [pɐɾˈtiðu ʁɛpuβliˈkɐnu puɾtuˈɣeʃ]) was a Portuguese political party formed during the late years of the constitutional monarchy that proposed and later brought about the replacement of the monarchy with the Portuguese First Republic. When the Republic was established on the 5 October 1910 Revolution, the members of the party initially stood together, but soon began splitting into different parties, including the Democratic Party, Republican Union, and Evolutionist Party, some of which themselves later merged or split to form the Democratic Leftwing Republican Party, Reformist Party, Centrist Republican Party, Popular Party, Radical Party, Republican Liberal Party, Liberal Republican Union, Reconstitution Party and Nationalist Republican Party.
=== Other invasive electrical methods === Auditory brainstem implant, which provides a sense of sound to a person who cannot use a cochlear implant due to a damaged or missing cochlea or auditory nerve Functional electrical stimulation (FES) Vagus nerve stimulation (VNS) Hypoglossal nerve stimulation, an option for some patients who have obstructive sleep apnea Percutaneous tibial nerve stimulation (PTNS) for the treatment of incontinence. Peripheral nerve stimulation (PNS, which refers to stimulation of nerves beyond the spine or brain, and may be considered to include occipital or sacral nerve stimulation) Occipital nerve stimulation (ONS) Sacral nerve stimulation (SNS) / sacral neuromodulation (SNM)
Sources: en.wikipedia.org
The deportees were released on 19 December and allowed to travel to Cairo and then, with Jamal Husseini, to Beirut where a new Arab Higher Committee (or Higher National Committee) was established. Amin al-Husayni was not a member of the Arab delegation but the delegation was clearly acting under his direction. The London Conference commenced on 7 February 1939, but the Arab delegation refused to sit in the same room with the Jewish delegation present, and the conference broke up in March with no success. In May 1939, the British government presented its 1939 White Paper which was rejected by both sides. The White Paper had, in effect, repudiated the Balfour Declaration. According to Benny Morris, Amin al-Husayni "astonished" the other members of the Arab Higher Committee by turning down the White Paper. Al-Husayni turned the advantageous proposal down because "it did not place him at the helm of the future Palestinian state." The deportees were not allowed to return to Palestine until 1941. Amin Al-Husayni spent the war years in occupied Europe, actively collaborating with the Nazi leadership. Amin and Jamal al-Husayni were involved in the 1941 pro-Nazi Rashidi revolt in Iraq. Amin again evaded capture by Britain but Jamal was captured in 1941 and interned in Southern Rhodesia, where he was held until November 1945 when he was allowed to move to Cairo. Husayn al-Khalidi returned to Palestine in 1943. Jamal al-Husayni returned to British Palestine in February 1946 as an official of the new Arab Higher Committee, by then recognised by the Mandate administration.
=== Thioredoxin reductase === Thioredoxin reductase uses a cysteine-selenocysteine pair to reduce the disulfide in thioredoxin. The selenocysteine is arranged in an unusual Sec-His-Glu catalytic triad, which tunes its pKa.
=== Primary structure === Chymopapain's zymogen is made up of a total of 352 residues, and it has a weight of approximately 23.78kDa. Three different regions can be distinguished inside the precursor's chain.
==== Vaal Civic Association ==== The organisation which spearheaded the 3 September march was the VCA, a residents' organisation partly modelled on the successful Soweto Civic Association. Launched on 9 October 1983, VCA was an affiliate of the UDF, and two senior officials in the UDF's Transvaal branch – Curtis Nkondo and Elliot Shabangu – were guest speakers at its launch in October 1983. Its inaugural chairman was Lord McCamel, a local priest with a parish in Evaton, and his deputy was Esau Ralitsela.
From the example above, if the descendant with genes A1 and B underwent another speciation event where gene A1 duplicated, the new species would have genes B, A1a, and A1b. In this example, genes A1a and A1b are symparalogs.
Sources: en.wikipedia.org
In late 2009, UK newspapers began referring to the drug as meow or miaow (sometimes doubled as meow meow or miaow miaow), a name that was almost unknown on the street at the time. In November 2009, the tabloid newspaper, The Sun published a story stating that a man had ripped off his own scrotum whilst using mephedrone. The story was later shown to be an online joke posted on mephedrone.com and later included in a police report, with the caveat that it could be unreliable. The police report was used as a source for the story in The Sun. Other myths the media often repeated during 2010 were that mephedrone had led to the deaths of over 20 people, teachers were unable to confiscate the drug from pupils, and the government was too slow to ban the drug. Parallels were drawn between the media coverage of mephedrone and a piece of satire by Chris Morris in 1997 on Brass Eye when he tricked public figures into talking of the dangers of taking the fictional legal drug "cake". The Advisory Council on the Misuse of Drugs (ACMD) have suggested that the media coverage of the drug led to its increased usage. Jon Silverman, a former BBC Home Affairs Correspondent, has written two articles discussing how the media had a strong influence over the UK government's drugs policy, particularly in that the government wished to demonstrate they were being "tough" on drugs. A survey of 1000 secondary school pupils and university students in Tayside, conducted in February 2010, found that 20% had previously taken mephedrone.
== Predicted properties == Other than nuclear properties, no properties of darmstadtium or its compounds have been measured; this is due to its extremely limited and expensive production and the fact that darmstadtium (and its parents) decays very quickly. Properties of darmstadtium metal remain unknown and only predictions are available.
=== Bacara Club === Peters no longer holds an ownership stake in the Miami Beach nightclub Bacara Club, which opened in April 2026. Having sold his share in the venue, he said: "I already made my bag, I flipped it.. I do not have any ownership anymore.. it is funny though.. they thought me not being there.. did they actually think the club is gonna work without me but it's all good, I made my bag."
=== Analogues and derivatives === Analogues and derivatives of nicotine are known. These compounds, often structurally similar and sharing affinity for nicotinic acetylcholine receptors, have applications in pharmacology (e.g., smoking cessation), pest control, and neuroscience research (e.g., multiple domain cognitive enhancement, neuroprotection).
Overuse injuries of the musculoskeletal system because of repetitive exercise, with young athletes (under the age of 19) particularly at risk Overtraining syndrome may lead to persistent dysfunction of a number of body systems High volumes of training with insufficient calorie intake puts athletes—particularly female ones—at risk for RED-S Aerobic exercise may not be as time-efficient as other cardiovascular training methods. For example, High-intensity interval training (HIIT) has been shown to provide similar benefits in a fraction of the time spent exercising per week. Both the health benefits and the performance benefits, or "training effect", require that the duration and the frequency of exercise both exceed a certain minimum. Most authorities suggest at least twenty minutes performed at least three times per week.
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.
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, commonly written as TKPRPGP. It shares the first four residues with tuftsin and carries three prolines in the chain. The proline-rich tail is the main structural feature that separates it from the parent tetrapeptide.