Selank 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.
Updated 2026-03-03. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Route studied | Intranasal | Predominant route in published reports |
| Circulation stability | Short, minutes scale | Peptidases cleave it; the tail slows the process |
| Analytical method | RP-HPLC with mass spectrometry | Used for identity and purity assessment |
| Reported outcome domains | Anxiety and cognitive measures | Derived from small, mostly regional trials |
| Regulatory status | Marketed in Russia | Availability outside that market is limited |
The primary structure of Selank is Thr-Lys-Pro-Arg-Pro-Gly-Pro, corresponding to the molecular formula C33H57N11O9 and a monoisotopic mass of roughly 751.9 daltons. The N-terminal threonine and the arginine residue in the fourth position are shared with tuftsin, which carries the sequence Thr-Lys-Pro-Arg. The three additional residues at the C-terminus, Pro-Gly-Pro, extend the chain and are associated with greater resistance to enzymatic degradation. This extension also separates Selank from the shorter parent peptide.
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.
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.
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.
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.
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.
People of any age can develop a keloid. Children under 10 are less likely to develop keloids, even from ear piercing. Keloids may also develop from pseudofolliculitis barbae; continued shaving when one has razor bumps will irritate the bumps, infection, and over time, keloids will form. Persons with razor bumps are advised to stop shaving for the skin to repair itself before undertaking any form of hair removal. The tendency to form keloids is speculated to be hereditary. Keloids can tend to appear to grow over time without even piercing the skin, almost acting out a slow tumorous growth; the reason for this tendency is unknown. Extensive burns, either thermal or radiological, can lead to unusually large keloids; these are especially common in firebombing casualties and were a signature effect of the atomic bombings of Hiroshima and Nagasaki. The true incidence and prevalence of keloid in the United States are not known. Indeed, there has never been a population study to assess the epidemiology of this disorder. In his 2001 publication, Marneros stated that "reported incidence of keloids in the general population ranges from a high of 16% among the adults in the Democratic Republic of the Congo to a low of 0.09% in England," quoting from Bloom's 1956 publication on heredity of keloids. Clinical observations show that the disorder is more common among sub-Saharan Africans, African Americans and Asians, with unreliable and very wide estimated prevalence rates ranging from 4.5 to 16%.
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Bones serve a variety of mechanical functions. Together the bones in the body form the skeleton. They provide a frame to keep the body supported, and an attachment point for skeletal muscles, tendons, ligaments and joints, which function together to generate and transfer forces so that individual body parts or the whole body can be manipulated in three-dimensional space (the interaction between bone and muscle is studied in biomechanics). Bones protect internal organs, such as the skull protecting the brain or the ribs protecting the heart and lungs. Because of the way that bone is formed, bone has a high compressive strength of about 170 MPa (1,700 kgf/cm2), poor tensile strength of 104–121 MPa, and a very low shear stress strength (51.6 MPa). This means that bone resists pushing (compressional) stress well, resist pulling (tensional) stress less well, but only poorly resists shear stress (such as due to torsional loads). While bone is essentially brittle, bone does have a significant degree of elasticity, contributed chiefly by collagen. Mechanically, bones also have a special role in hearing. The ossicles are three small bones in the middle ear which are involved in sound transduction.
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=== Potential data collection by the Chinese government === Concerns have been raised about the potential control and influence of the Chinese government over TikTok's owner, ByteDance, in particular the extraterritorial implications of China's 2017 National Intelligence Law. An article in the law insists that all organizations and citizens shall "support, assist and cooperate with national intelligence efforts." Analysts differ in their assessments of the data collection risks. Jim Lewis of the Center for Strategic and International Studies said TikTok would have no right to appeal requests for data made by the Chinese government. Some cybersecurity experts say individual users are not at risk. The United States has not offered any evidence of TikTok sharing such information with Chinese authorities. Keeping user data within the United States became the motivation behind TikTok's Project Texas.
Biological machines are considered to be nanoscale devices (such as molecular proteins) in a living system that convert various forms of energy to mechanical work in order to drive crucial biological processes such as intracellular transport, muscle contractions, ATP generation and cell division.
Britain wanted to see an end to Spanish rule in South America and ultimately tap the monopoly of the important potential markets there. At the same time they wanted Spain as an ally to keep the balance of power in post-Napoleonic Europe. To fulfil this, Britain went covert in support of the Revolutionaries in South America. In a kind of private free enterprise going by the law, she sent men, financial and material support to help the insurgents fight against Spain. One of the most significant contributions were the British Legions, a volunteer unit that fought under Simón Bolívar. This force numbered upwards of 6,000 men – the majority of whom were composed of veterans of the Napoleonic Wars. In combat their greatest achievements were at Boyacá (1819), Carabobo (1821), Pichincha (1822) and Ayacucho (1824) which secured independence for Colombia, Venezuela, Ecuador and Peru from Spanish rule respectively. Bolívar described the Legions and all who served in them as "the saviours of my country". Many members of the Royal Navy also volunteered for the revolutionary forces. The most famous being Thomas Cochrane who reorganised the Chilean navy, most of whom were composed of Royal Navy veterans. Amongst many feats he captured the Spanish fortress of Valdivia in 1820; and in the same year he captured the flagship of the Spanish South American fleet, the Esmeralda, in the port of Callao. As well as helping Chile gain independence from Spain Cochrane did the same for Peru too by mounting an effective blockade and transporting troops.
A distinguishing feature of SARS‑CoV‑2 is its incorporation of a polybasic site cleaved by furin, which appears to be an important element enhancing its virulence. It was suggested that the acquisition of the furin-cleavage site in the SARS-CoV-2 S protein was essential for zoonotic transfer to humans. The furin protease recognises the canonical peptide sequence RX[R/K] R↓X where the cleavage site is indicated by a down arrow and X is any amino acid. In SARS-CoV-2 the recognition site is formed by the incorporated 12 codon nucleotide sequence CCT CGG CGG GCA which corresponds to the amino acid sequence P RR A. This sequence is upstream of an arginine and serine which forms the S1/S2 cleavage site (P RR A R↓S) of the spike protein. Although such sites are a common naturally-occurring feature of other viruses within the Subfamily Orthocoronavirinae, it appears in few other viruses from the Beta-CoV genus, and it is unique among members of its subgenus for such a site. The closest relatives to SARS-CoV-2, including BANAL-20-52, RaTG13, Pangolin P4L, and SARS-CoV-1, lack the RRAR insertion. The furin cleavage site PRRAR↓ is highly similar to that of the feline coronavirus, an alphacoronavirus 1 virus. Viral genetic sequence data can provide critical information about whether viruses separated by time and space are likely to be epidemiologically linked. With a sufficient number of sequenced genomes, it is possible to reconstruct a phylogenetic tree of the mutation history of a family of viruses.
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Arthropods comprise the largest phylum of invertebrates in the animal kingdom with over a million known species. Insects possess segmented bodies supported by a hard-jointed outer covering, the exoskeleton, made mostly of chitin. The segments of the body are organized into three distinct parts, a head, a thorax and an abdomen. The head typically bears a pair of sensory antennae, a pair of compound eyes, one to three simple eyes (ocelli) and three sets of modified appendages that form the mouthparts. The thorax has three pairs of segmented legs, one pair each for the three segments that compose the thorax and one or two pairs of wings. The abdomen is composed of eleven segments, some of which may be fused and houses the digestive, respiratory, excretory and reproductive systems. There is considerable variation between species and many adaptations to the body parts, especially wings, legs, antennae and mouthparts. Spiders a class of arachnids have four pairs of legs; a body of two segments—a cephalothorax and an abdomen. Spiders have no wings and no antennae. They have mouthparts called chelicerae which are often connected to venom glands as most spiders are venomous. They have a second pair of appendages called pedipalps attached to the cephalothorax. These have similar segmentation to the legs and function as taste and smell organs. At the end of each male pedipalp is a spoon-shaped cymbium that acts to support the copulatory organ.
The general strategy adopted by most present-day competitive bodybuilders is to make muscle gains for most of the year (known as the "off-season") and, approximately 12–14 weeks from competition, lose a maximum of body fat (referred to as "cutting") while preserving as much muscular mass as possible. The bulking phase entails remaining in a net positive energy balance (calorie surplus). The amount of a surplus in which a person remains is based on the person's goals, as a bigger surplus and longer bulking phase will create more fat tissue. The surplus of calories relative to one's energy balance will ensure that muscles remain in a state of anabolism. The cutting phase entails remaining in a net negative energy balance (calorie deficit). The main goal of cutting is to oxidize fat while preserving as much muscle as possible. The larger the calorie deficit, the faster one will lose weight. However, a large calorie deficit will also create the risk of losing muscle tissue. The bulking and cutting strategy is considered effective because there is a well-established link between muscle hypertrophy and being in a state of positive energy balance. A sustained period of caloric surplus will allow the athlete to gain more fat-free mass than they could otherwise gain under eucaloric conditions. Some gain in fat mass is expected, which athletes seek to oxidize in a cutting period while maintaining as much lean mass as possible. However, it is unclear whether one can maintain enough fat-free mass during cutting for the overall process to be worth it.
In 2003, following the Soccer Australia team's failure to qualify for the 2002 FIFA World Cup, allegations of fraud and mismanagement were levelled at Soccer Australia by elements within the Australian press including the ABC. Soccer Australia commissioned an independent inquiry known as the Crawford Report as a result of the Australian government's threat to withdraw funding to the sport. Any political interference would have constituted a breach of FIFA statutes. The findings of the report were critically analysed by the board of Soccer Australia who believed that the recommendations contained therein were not capable of being implemented. The report recommended, among other things, the reconstitution of the organisation with an interim board headed by prominent businessman Frank Lowy. Some three months after Lowy's appointment, Soccer Australia was placed into liquidation and the Australian Soccer Association (ASA) was created and seized control of the premier soccer competitions and teams without encompassing the Crawford Report recommendations and effectively disenfranchised all other organisations and parties with an interest in Soccer Australia. The Australian government provided approximately $15 million to the ASA. On 1 January 2005, ASA renamed itself Football Federation Australia (FFA), aligning with the international usage of the name "football" in preference to "soccer" and, by a more distinct name, distancing itself from the failings of the former Soccer Australia. It coined the phrase "old soccer, new football" to emphasise this.
The most common first symptom of all snakebites is an overwhelming fear, which may contribute to other symptoms, and may include nausea and vomiting, diarrhea, vertigo, fainting, tachycardia, and cold, clammy skin. Snake bites can have a variety of different signs and symptoms depending on their species. Dry snakebites and those inflicted by a non-venomous species may still cause severe injury. The bite may become infected from the snake's saliva. The fangs sometimes harbor pathogenic microbial organisms, including Clostridium tetani, and may require an updated tetanus immunization. Most snakebites, from either a venomous or a non-venomous snake, will have some type of local effect. Minor pain and redness occur in over 90 percent of cases, although this varies depending on the site. Bites by vipers and some cobras may be extremely painful, with the local tissue sometimes becoming tender and severely swollen within five minutes. This area may also bleed and blister and may lead to tissue necrosis. Other common initial symptoms of pit viper and viper bites include lethargy, bleeding, weakness, nausea, and vomiting. Symptoms may become more life-threatening over time, developing into hypotension, tachypnea, severe tachycardia, severe internal bleeding, altered sensorium, kidney failure, and respiratory failure. Bites by some snakes, such as the kraits, coral snake, Mojave rattlesnake, and the speckled rattlesnake, may cause little or no pain, despite their serious and potentially life-threatening venom.
== Safety == HATU has been shown to induce allergic reactions. In vivo dermal sensitization studies according to OECD 429 confirmed HATU is a moderate skin sensitizer, showing a response at 1.2 wt% in the Local Lymph Node Assay (LLNA) placing it in Globally Harmonized System of Classification and Labelling of Chemicals (GHS) Dermal Sensitization Category 1A. Thermal hazard analysis by Differential scanning calorimetry (DSC) shows HATU is potentially explosive.
Sources: en.wikipedia.org
Reports describe effects on GABA-A receptor expression, monoamine turnover, and neurotrophic factor levels. These are proposed mechanisms drawn mainly from animal models. No single molecular target has been established.
Intranasal delivery is the route described in most published work. It is used because the peptide is degraded quickly once it reaches circulation. Direct evidence of brain penetration in humans is lacking.
Most trials are small, regionally concentrated, and often lack rigorous blinding or placebo control. Independent replication is limited. Reviews in English generally rate the evidence as preliminary.
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.