Intranasal delivery raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2026-07-03. Anything still debated is marked as such rather than presented as settled.
Pharmacokinetic data are sparse and largely derived from animal work. After intranasal administration the peptide appears in plasma within minutes, and reported half-lives are short, on the order of minutes to tens of minutes. Degradation proceeds through ordinary proteolytic cleavage into constituent amino acids and smaller fragments. Direct evidence that intact Selank reaches brain tissue in meaningful amounts is limited, and the extent of blood-brain barrier penetration is debated. Some authors argue that fragments, not the parent peptide, carry much of the observed activity.
Published clinical work is concentrated in Russian-language journals and generally involves small samples without independent replication. Systematic reviews in English note the shortage of randomised, placebo-controlled trials and the difficulty of verifying methods from translated reports. Outcome measures vary between studies, which complicates pooling of results. Interest in the compound as a cognitive or anxiolytic agent therefore rests on a thinner evidence base than the volume of citations suggests. Replication in well-powered trials with preregistered endpoints would be needed before firm conclusions about efficacy can be drawn.
Proposed mechanisms centre on the GABAergic system. Animal and tissue studies report changes in GABA-A receptor expression and reduced activity of GABA transaminase, the enzyme that degrades GABA. Effects on monoamine turnover, including serotonin and dopamine pathways, are also described, and a separate line of work links the peptide to increased expression of brain-derived neurotrophic factor in hippocampal tissue. Most of these findings come from rodent models and cell preparations. How the individual observations combine into a single coherent mode of action is not settled.
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.
Selank is studied chiefly as an animal-model anxiolytic with proposed secondary effects on memory and immune signaling. Reported mechanisms include modulation of the GABA-A receptor complex, inhibition of enkephalin-degrading enzymes, and shifts in monoamine turnover within limbic structures. Some experiments describe increased expression of brain-derived neurotrophic factor in the hippocampus after repeated dosing. No single molecular target has been confirmed, and the peptide does not bind any receptor with the selectivity typical of a conventional small-molecule drug. Mechanism therefore remains a set of hypotheses rather than an established pathway.
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.
| Property | Value | Notes |
|---|---|---|
| Primary route studied | Intranasal | Also examined parenterally in animal work |
| Reported plasma half-life | Minutes to tens of minutes | Values vary widely between reports |
| Main model systems | Rodent behavioural and cell assays | Human trials are few and small |
| Principal proposed targets | GABA-A receptor, GABA transaminase | Monoamine and neurotrophic pathways also reported |
| Evidence grade | Preliminary | Limited independent replication |
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.
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.
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.
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.
The compound has a calculated molecular weight near 751.9 daltons and carries a net positive charge at physiological pH because of its arginine residue. It dissolves freely in water and in common aqueous buffers, and typically appears as a white or off-white lyophilized powder. The amide backbone makes the molecule susceptible to peptidases, which limits oral use and favors intranasal or parenteral routes. Nomenclature in the literature varies: the substance is also described by the sequence abbreviation TP-7 and by a Russian trade designation.
Since most of the dissolved CO2 remains as CO2 molecules, Ka1(apparent) has a much larger denominator and a much smaller value than the true Ka1. The bicarbonate ion is an amphoteric species that can act as an acid or as a base, depending on pH of the solution. At high pH, it dissociates significantly into the carbonate ion (CO32–):
=== Generic names === Drostanolone propionate is the generic name of the drug and its BANMTooltip British Approved Name, while dromostanolone propionate is the USANTooltip United States Adopted Name and USPTooltip United States Pharmacopeia; there is no INNTooltip International Nonproprietary Name for this form. The generic name of the unesterified form of the drug is drostanolone or dromostanolone and the former is its INNTooltip International Nonproprietary Name, BANTooltip British Approved Name, and DCFTooltip Dénomination Commune Française while there is no USANTooltip United States Adopted Name.
During the BBC's election night coverage, Jeremy Paxman asked Galloway about whether he was happy to have removed one of the few black women in parliament, He replied: "I don't believe that people get elected because of the colour of their skin. I believe that people get elected because of their record and because of their policies". Oona King later told BBC Radio 4's Today programme that she found Paxman's line of questioning inappropriate. Galloway "shouldn't be barred from running against me because I'm a black woman. ... I was not defined, or did not wish to be defined, by either my ethnicity or religious background".
In February 2025, Bukele offered Secretary of State Rubio to accept non-Salvadoran deportees from the United States, including convicted American prisoners "of U.S. citizenship and legal residents". Rubio described the offer as the "most unprecedented and extraordinary migratory agreement anywhere in the world". Bukele stated that these "dangerous American criminals" would be incarcerated in CECOT. In March 2025, the United States deported 238 alleged members of the Venezuelan gang Tren de Aragua to El Salvador. Bukele met Trump in the Oval Office in April 2025 where they discussed immigration. Both Trump and Bukele stated they could not unilaterally release Kilmar Abrego Garcia, a migrant deported due to an administrative error.
Trump names himself as the headliner for the "Great American State Fair" semiquincentennial event, organized by Freedom 250, in Washington D.C., after several artists pull out over concerns that the event became politicized by Trump. Martina McBride, Young MC, Bret Michaels, and the Commodores were among the artists who pulled out. A revised lineup includes artists such as Flo Rida, Milli Vanilli, and Vanilla Ice. May 31 – The National Basketball Association announces that the logo for the Larry O'Brien Championship Trophy will be displayed on the basketball courts of Frost Bank Center in San Antonio, Texas, and Madison Square Garden in New York City for the upcoming NBA Finals between the San Antonio Spurs and New York Knicks, making it the first time the logo decal will be placed on the NBA court during the NBA Finals since 2009.
Sources: en.wikipedia.org
Therefore, Akt promotes G1 phase progression in a positive feedback loop. Akt promotes cyclin D1 translation via indirect activation of mTOR. mTOR increases translation of cyclin D1 by activating ribosomal protein S6K, and inhibiting eukaryotic translation initiation factor 4E-binding protein (4E-BP), thus increasing eIF4e activity. Akt both indirectly and directly regulates cyclin-dependent kinase (CDK) inhibitors p21Cip1 and p27Kip1, allowing cell cycle progression. Akt phosphorylates p27Kip1 at Thr157, preventing its nuclear import. In addition, Akt phosphorylates Thr145 and Ser146 of p21Cip1, preventing PCNA binding and decreasing stability. Akt phosphorylation of Foxo transcription factors also affects the cell cycle, as inhibitory phosphorylation of FoxO4 (also named AFX) prevents p27 gene expression. Akt phosphorylates many proteins involved in polymerisation and stabilisation of the actin cytoskeleton. In normal cells, this can either increase the stability of cytoskeleton components or promote migration via remodelling. Examples are listed below:
The earliest known regulators of gene expression were proteins known as repressors and activators – regulators with specific short binding sites within enhancer regions near the genes to be regulated. Later studies have shown that RNAs also regulate genes. There are several kinds of RNA-dependent processes in eukaryotes regulating the expression of genes at various points, such as RNA interference repressing genes post-transcriptionally, long non-coding RNAs shutting down blocks of chromatin epigenetically, and enhancer RNAs inducing increased gene expression. Bacteria and archaea have also been shown to use regulatory RNA systems such as bacterial small RNAs and CRISPR. Fire and Mello were awarded the 2006 Nobel Prize in Physiology or Medicine for discovering microRNAs (miRNAs), specific short RNA molecules that can base-pair with mRNAs.
The YES/YAS assay is performed in 96-well microtiter plates. Total assay time is usually 2–3 days, but faster protocols (18 hrs. exposure time) using induced cell lysis have been developed. Several yeast cell lines have been developed for the YES and YAS assay, both proprietary and publicly available. Commercial kits with all necessary ingredients and detailed instructions are also available. Substances with an activating or inhibitory effect on the estrogen and/or androgen receptor of organisms may interfere with reproduction, affect the metabolism and immune system and induce the formation of tumors. This assay is suitable for detecting numerous natural and synthetic hormonally active substances such as environmental toxins from everyday products, e.g. birth control pill ingredients (17α-ethinylestradiol), synthetic materials (bisphenol A, phthalates), pesticides (methoxychlorine) and non-ionic surfactants (alkylphenols). The test has a good reproducibility and concordance with literature data of in vivo or in vitro data.
Since Urbain was on the commission which made the decision, its objectivity could be questioned; furthermore, Welsbach protested that Urbain's spectral evidence was weak and argued that his rival's lutetium was very impure, but to no avail. After Urbain's names were recognized, neoytterbium was reverted to ytterbium. The controversy died down after 1910, only to be reignited with the discovery of element 72. Urbain claimed in 1911 to have discovered a new rare earth named celtium and identified it as element 72. However, Niels Bohr had demonstrated from his quantum theory that element 72 had to be a group 4 element and not a rare earth, and based on an idea by Fritz Paneth, Bohr's friend George de Hevesy worked with Dirk Coster to search for it in zirconium minerals. This they succeeded in doing, discovering hafnium in 1923. This discovery announcement, being in direct conflict with Urbain's celtium, ignited a controversy on element 72 throughout the 1920s; the resulting investigations on the nature of Urbain's celtium, since it was not the same as hafnium, reopened the case on element 71. The physicists Hans M. Hansen and Sven Werner, at Bohr's Copenhagen institute, found in 1923 that Welsbach's 1907 samples of cassiopeium had been pure element 71, while Urbain's 1907 lutecium samples only contained traces of element 71 and his 1911 samples identified as celtium were actually pure element 71 – confirming Welsbach's criticism.
There have been a significant number of publications since then, and a Food and Drug Administration panel voted, with some controversy, 20:3 that available studies "supported a signal of harm", but voted 22:1 to keep the drug on the market. The meta-analysis was not supported by an interim analysis of the trial designed to evaluate the issue, and several other reports have failed to conclude the controversy. This weak evidence for adverse effects has reduced the use of rosiglitazone, despite its important and sustained effects on glycemic control. Safety studies are continuing. In contrast, at least one large prospective study, PROactive 05, has shown that pioglitazone may decrease the overall incidence of cardiac events in people with type 2 diabetes who have already had a heart attack.
Sources: en.wikipedia.org
Reports describe modulation of GABA signalling, changes in monoamine turnover and effects on neurotrophic factor expression. These observations come mainly from animal and cell studies. A single unifying mechanism has not been demonstrated.
The peptide enters plasma rapidly and is broken down by ordinary proteases into amino acids and shorter fragments. Reported half-lives are short. Whether meaningful amounts of the intact molecule reach the brain is an open question.
Most clinical reports are small, published in Russian and not independently replicated. English-language reviews highlight the absence of large randomised trials. Conclusions about efficacy should be treated as provisional.
Intranasal administration predominates in both animal and human research because it avoids hepatic first-pass metabolism. Injectable and intraperitoneal routes appear in animal work mainly for comparison.