A practical reference on blood-brain barrier: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-07-14 and is reviewed periodically as new material appears.
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.
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.
Published clinical evidence is limited. Most controlled trials were conducted in Russia, enrolled modest numbers of participants, and appeared in Russian-language journals, which restricts independent verification. Reported outcomes include lower anxiety scores, improved attention and memory measures, and changes in fatigue ratings. Reviews written in English note methodological limitations such as small samples and inconsistent endpoints. Whether the compound produces clinically meaningful benefit relative to established anxiolytics is therefore an open question rather than an established finding.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences as a structural analogue of tuftsin, a naturally occurring tetrapeptide fragment of the immunoglobulin heavy chain. The added Pro-Gly-Pro tail was intended to slow enzymatic degradation and extend biological activity. In Russia it is registered as an anxiolytic nasal preparation, while regulators elsewhere have not approved it for clinical use.
Proposed mechanisms centre on modulation of the GABAergic system, with reports of altered expression of genes related to GABA-A receptor subunits and changed monoamine turnover. Some studies describe inhibition of enkephalinase, the enzyme that degrades endogenous enkephalins, which may prolong opioid peptide signalling. Effects on brain-derived neurotrophic factor and on cytokine expression have also been reported. These findings come largely from animal models and small human studies, and the precise primary target remains unresolved.
| 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 |
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.
Naming conventions place Selank in the same research family as Semax, another Russian-developed peptide investigated for cognitive effects. The two compounds share a lineage but differ in sequence and in the biological systems proposed as their targets. Semax descends from ACTH fragments, whereas Selank descends from tuftsin. Publications sometimes identify Selank by its full peptide sequence or by laboratory codes rather than one uniform trade name. Because replication outside Russia is limited, reports on its properties are best read alongside the study design and the purity of the material tested.
Selank is a synthetic heptapeptide developed in Russia during the 1990s. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences designed it as a stabilized analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The compound has been studied primarily for its reported anxiolytic and nootropic effects. It remains largely unknown in Western pharmacology and is not approved as a medicine by major regulators such as the FDA or the EMA.
However, later research showed that the human MHC IIb was in fact IIx, indicating that the IIB is better named IIX. IIb is expressed in other mammals, so is still accurately seen (along with IIB) in the literature. Non human fiber types include true IIb fibers, IIc, IId, etc.
In July 2016, the Centers for Disease Control issued a report stating that between 2010 and 2015, US poison control centers received 660 reports of exposure to kratom. Medical outcomes associated with kratom exposure were reported as minor (minimal signs or symptoms, which resolved rapidly with no residual disability) for 162 (24.5%) exposures, moderate (non-life-threatening, with no residual disability, but requiring some form of treatment) for 275 (41.7%) exposures, and major (life-threatening signs or symptoms, with some residual disability) for 49 (7.4%) exposures. Overall, 92.6% of outcomes were resolved with no residual disability. One death was reported in a person who was exposed to the medications paroxetine (an antidepressant) and lamotrigine (an anticonvulsant and mood stabilizer) in addition to kratom. For 173 (26.2%) exposure calls, no effects were reported, or poison center staff members were unable to follow up regarding effects. A 2019 report from the American Association of Poison Control Centers (AAPCC) noted that kratom use was increasing rapidly, with 1807 kratom exposures and a 52-fold increase occurring over the years 2011 to 2017. Most exposures occurred intentionally by adult males in their homes, with 32% of the incidents requiring admission to a health care facility and half of the admissions as a serious medical condition. Multiple-substance exposures were associated with a higher number of hospitalizations than kratom-only exposures and involved 11 deaths, including two due to kratom alone.
In 2010, President Barack Obama signed the Patient Protection and Affordable Care Act into law. Since the 2022 U.S. Supreme Court decision Dobbs v. Jackson Women's Health Organization, which effectively overruled Roe v. Wade (1973), abortion in the United States is no longer federally protected but is subject to the laws of each state or territory.
3D printing could be a precise tool in designing pills to house several drugs, because the control over the structure of pills that 3D Printing provides could in theory help make better pills for drugs that have specific release times. The technology allows the pills to transport to the targeted area and degrade safely in the body. Besides, 3D printing might become more useful in medical implants. An example includes a surgical team that has designed a tracheal splint made by 3D printing to improve the respiration of a patient. This example shows the potential of 3D printing, which allows physicians to develop new implant and instrument designs easily. Overall, in the future of medicine, 3D printing will likely be crucial as it can be used in surgical planning, artificial and prosthetic devices, drugs, medical implants, and more.
== Further reading == Schotten, C. (1884). "Ueber die Oxydation des Piperidins". Berichte der deutschen chemischen Gesellschaft. 17 (2): 2544–2547. doi:10.1002/cber.188401702178. Baumann, E. (1886). "Ueber eine einfache Methode der Darstellung von Benzoësäureäthern". Berichte der deutschen chemischen Gesellschaft. 19 (2): 3218–3222. doi:10.1002/cber.188601902348.
Sources: en.wikipedia.org
By far the largest carnivore in its environment, Tyrannosaurus rex was most likely an apex predator, preying upon hadrosaurs, juvenile armored herbivores like ceratopsians and ankylosaurs, and possibly sauropods. The question of whether Tyrannosaurus was an apex predator or a pure scavenger was among the longest debates in paleontology. Most paleontologists today accept that Tyrannosaurus was a predator, and the idea of Tyrannosaurus being primarily a scavenger has been discredited. Some specimens of Tyrannosaurus rex are nearly complete skeletons. Soft tissue and proteins have been reported in at least one of these specimens. The abundance of fossil material has allowed significant research into many aspects of the animal's biology, including its life history and biomechanics. The feeding habits, physiology, and potential speed of Tyrannosaurus rex are a few subjects of debate. Its taxonomy is also controversial. The Asian Tarbosaurus bataar is very closely related to Tyrannosaurus and has sometimes been seen as a species of this genus. Several North American tyrannosaurids have been synonymized with Tyrannosaurus, while some Tyrannosaurus specimens have been proposed as distinct species. The validity of these species, such as the more recently discovered T. mcraeensis, is contentious. Tyrannosaurus has been one of the best-known dinosaurs since the early 20th century. Its fossils have been a popular attraction in museums and it has appeared in media like Jurassic Park.
(–NS(Cl)–)3 + 3 NaOR → (–NS(OR)–)3 + 3 NaCl (–NS(Cl)–)3 + 3 AgX → (–NS(X)–)3 + 3 AgCl Treating thiazyl chloride with sulfur in the presence of antimony pentachloride gives dithionitronium hexachloroantimonate:
According to the White House's website, whitehouse.gov, more than 200 organizations have stated their support for the OBBBA, including AT&T, Comcast, American Airlines, Delta Air Lines, the National Retail Federation, and the National Taxpayers Union. Trump has claimed that the bill is the "single most popular bill ever signed", a claim that CNN disputed, saying "That is an up-is-down reversal of reality. ... While polls can be off, this bill wouldn't be popular – let alone the most popular US bill ever signed – even with a massive and widespread polling error."
In February 2022, The Wall Street Journal reported that "Mental-health professionals around the country are growing increasingly concerned about the effects on teen girls of posting sexualized TikTok videos." In March 2022, a coalition of US state attorneys general launched an investigation into TikTok's effect on children's mental health. In June 2022, TikTok introduced the ability to set a maximum uninterrupted screen time allowance, after which the app blocks off the ability to navigate the feed. The block only lifts after the app is exited and left unused for a set period of time. Additionally, the app features a dashboard with statistics on how often the app is opened, how much time is spent browsing it and when the browsing occurs. Since 2021, it has been reported that accounts engaging with contents related to suicide, self-harm, or eating disorders were shown more similar videos. Some users were able to circumvent TikTok filters by writing in code or using unconventional spelling. The company has faced multiple lawsuits pertaining to wrongful deaths. TikTok said it is working to break up these "rabbit holes" of similar recommendations. US searches for eating disorder receive a prompt that offers mental health resources. In 2021, the platform revealed that it will be introducing a feature that will prevent teenagers from receiving notifications past their bedtime. The company will no longer send push notifications after 9 pm to users aged between 13 and 15. For 16 to 17 year olds, notifications will not be sent after 10 pm.
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.
It is a seven-amino-acid peptide, Thr-Lys-Pro-Arg-Pro-Gly-Pro, produced by chemical synthesis rather than extracted from biological tissue. Its design is based on tuftsin, a natural immunomodulatory tetrapeptide. The C-terminal Pro-Gly-Pro segment is a common stabilising motif in short regulatory peptides.