Selank: benefits, side effects, nasal spray and what the research shows

Selank is a heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro ^[1]. The first four amino acids are tuftsin, a short peptide that comes from the heavy chain of immunoglobulin G; Selank adds a Pro-Gly-Pro sequence to it. It was developed in Russia as an anxiolytic (anti-anxiety) drug, and much of the published research comes from the Institute of Molecular Genetics of the Russian Academy of Sciences and collaborating Russian institutes ^[5][6].

It is closely associated with Semax, another Russian heptapeptide that ends in the same Pro-Gly-Pro sequence, and the two are often sold together by research peptide vendors as “nootropics”.

The registered Russian product contains Selank as a diacetate salt, 1.5 mg per mL, in water with a methyl paraben preservative ^[9]. Vendors also sell “N-acetyl Selank” and “NA-Selank amidate”, versions with an acetyl group added to the start of the chain and, in the amidate, an amide group at the end. These modified forms are not the registered drug, and we found no published human studies of them. When people search what Selank is used for, the only official answer is the Russian label, which lists anxiety states, panic attacks, neurasthenia, asthenia, mood instability, sleep disturbances, adjustment disorders and the prevention and treatment of stress disorders ^[9].

Several mechanisms have been proposed, all from Russian laboratory work. In blood samples, Selank inhibited enzymes that break down enkephalins (natural opioid peptides) in a dose-dependent way, and researchers suggested this could explain its anti-anxiety effect ^[1]. In rats, Selank changed the expression of many genes involved in nerve signalling in the frontal cortex, with a pattern that correlated with the effects of GABA, leading the authors to propose that it acts partly as an allosteric modulator of the GABA system, the same system targeted by benzodiazepines ^[5].

In rats given alcohol long term, Selank prevented alcohol-related changes in the brain growth factor BDNF and improved performance on a memory test ^[6]. None of these mechanisms has been confirmed in human studies.

Two further lines of work fill out the Selank mechanism of action as its developers describe it. In human serum, Selank inhibited enkephalin-degrading enzymes with a half-maximal concentration of about 20 µM, and its five-amino-acid fragment was also active ^[11]. In preparations of brain-cell membranes, it changed the binding of radioactive GABA in a way the authors interpreted as positive allosteric modulation of GABA receptors, and it interacted with the effects of diazepam and olanzapine on that binding ^[12]. Both studies come from the developers’ network and have not been repeated independently.

Animal studies from the same Russian network report anti-anxiety effects in stressed rats, including when combined with diazepam ^[7], and memory-protective effects in alcohol-exposed rats ^[6]. These are mostly single-laboratory findings that have not been replicated by independent groups outside Russia.

The subsections below take the uses people ask about one at a time. In each case the question is whether there is human evidence, and if so how strong it is.

Anxiety is the one use with any human data. Three Russian studies compared Selank with, or added it to, benzodiazepines in patients with generalised anxiety, phobic or somatoform disorders and reported anti-anxiety effects (see Human studies below) ^[2][3][4]. None was placebo-controlled in a way that can be checked from the English abstracts, and none has been repeated outside Russia. The Selank benefits most often claimed online, such as calm without sedation, trace back to these studies and to the Russian product text, which describes anti-anxiety, anti-asthenic and cognition-improving effects ^[9].

Sleep disturbance is one of the indications on the Russian label ^[9]. We found no published study that measured sleep in people taking Selank, either by sleep recordings or by validated questionnaires, so any sleep effect is unmeasured.

The 2014 phenazepam comparison described a mild nootropic effect alongside the anti-anxiety effect ^[3], and the 2008 study described “psychostimulant” effects ^[2]. A 2020 brain-imaging study in 52 healthy participants found that Selank and Semax each changed resting-state connectivity between the right amygdala and the right temporal cortex within 20 minutes, compared with placebo ^[13]. That shows a measurable effect on brain activity, not better attention or memory. We found no study of Selank in ADHD, in children or adults.

Because tuftsin comes from an immune protein, Russian groups have also studied Selank’s effects on the immune system. In blood cells from patients with depression, Selank suppressed gene expression of the inflammatory messenger IL-6 in the test tube, although IL-6 protein in those cultures rose, and patients with generalised anxiety or neurasthenia given Selank for 14 days showed shifts in the balance of blood cytokines ^[14]. In cell culture, Selank added 24 hours before infection completely suppressed influenza virus replication; in infected animals, survival was highest when it was given preventively, and it raised interferon-alpha gene expression ^[15]. These are early findings with no clinical trial behind them.

Searches for “Selank withdrawal” mix two questions: whether Selank helps with withdrawal from other drugs, and whether stopping Selank itself causes withdrawal. On the first, the evidence is from rodents. A single injection of 0.3 mg/kg reduced a combined score of naloxone-precipitated morphine withdrawal signs in dependent rats by about 40%, slightly less than diazepam ^[16], and the same dose blocked alcohol-induced hyperactivity in mice ^[17]. On the second, see Safety below.

The human evidence consists of a few small studies published in Russian. In a 2008 randomised study, 62 patients with generalised anxiety disorder or neurasthenia received Selank or the benzodiazepine medazepam; the authors reported similar anti-anxiety effects, with Selank also having “antiasthenic and psychostimulant” effects ^[2]. A 2014 study comparing Selank with phenazepam in 60 patients with anxiety and somatoform disorders reported pronounced anti-anxiety and mild nootropic effects of Selank, lasting about a week after the last dose; the English abstract gives no statistical comparison between the drugs ^[3]. A 2015 study in 70 patients found that adding Selank to phenazepam reduced some of phenazepam’s side effects, such as sedation and memory problems ^[4].

These studies are small, were run by groups involved in developing the drug, and are available only in Russian with brief English abstracts. A 2021 US pharmacology review described Selank as a poorly studied Russian drug that was being sold to US consumers as a dietary supplement ^[8]. We found no trials registered or published outside Russia.

Outside anxiety, the human data are a cytokine study in patients treated for 14 days ^[14] and the brain-imaging study in healthy volunteers ^[13]. Taken together, this is weak evidence by international standards: small samples, developer involvement, short follow-up and outcomes that cannot be checked in detail from English sources.

There is no good answer from controlled trials. The clinical studies assessed patients over courses of treatment, including a 14-day course in the cytokine study ^[14], and the 2014 study reported that the anti-anxiety effect lasted about a week after the last dose ^[3]. The imaging study found changes in brain connectivity 5 to 20 minutes after a dose in healthy people ^[13], but that does not show a felt effect. Whether Selank works immediately, as some users report online, has not been tested.

Nasal use is the studied route. The only registered form is 0.15% nasal drops, and the Russian product information states that absolute bioavailability through the nose is 92.8%, that Selank appears in blood 30 seconds after dosing, and that it reaches brain tissue ^[9]. These figures come from the manufacturer’s label; we could not find the underlying study in English. The label also advises clearing the nose first because heavy mucus can reduce absorption ^[9].

We found no human studies of Selank given by injection. Vendor “Selank injection dosage charts” and subcutaneous protocols are not based on published human research. In mice, 300 µg/kg a day for 5 days given either into the nose or by injection into the abdomen reduced anxiety-like behaviour only in a naturally anxious strain, and the two routes changed different receptor measurements in the brain ^[18]. A product sold as a Selank “supplement” or capsule has no supporting data for absorption by mouth.

The Russian registered product is a 0.15% nasal solution, containing 1.5 mg of the active substance per mL ^[9]. The English abstracts of the human studies do not report the doses used, so we have not listed them. In rats, one study used 0.3 mg/kg per day by intraperitoneal injection for seven days ^[6]. No dose has been established outside the Russian product labelling, and animal doses cannot be converted to human doses.

The current Russian product information does not give a fixed regimen; it says the dose is set individually by the doctor according to the indication, age and clinical situation ^[9]. Other published animal doses are 0.3 mg/kg as a single injection in rats ^[16] and 300 µg/kg a day in mice ^[18]. So-called Selank dosage charts, including charts for anxiety or for 5 mg and 10 mg vials, are vendor material, not study data.

Questions about Selank 10mg reconstitution are arithmetic, not dosing: the concentration equals the amount of peptide divided by the volume of liquid added, so 10 mg in 2 mL gives 5 mg per mL. Our peptide calculator does this conversion, and the bacteriostatic water guide explains the diluent. Neither is a recommendation to use Selank.

The Russian product information lists possible allergic reactions and an unpleasant taste when drops reach the throat, and states that it should not be used in pregnancy, breastfeeding or under 18 ^[9]. The abstracts of the small clinical studies do not describe serious adverse effects ^[3][4], but the studies were not large or long enough to detect uncommon harms. The US FDA’s compounding page (as of April 2026) lists Selank acetate among substances previously placed in its category of bulk substances that may present significant safety risks in compounding, citing a potential for immunogenicity due to aggregation and peptide-related impurities; that nomination was later withdrawn ^[10].

Selank nasal spray side effects in the label are limited to the two above ^[9]. On withdrawal from Selank itself, we found no study that looked for withdrawal symptoms or dependence after stopping, so the absence of reports is not evidence of absence. The 2021 US review grouped Selank with GABA-acting drugs whose abuse and withdrawal potential it said should be evaluated before public access ^[8].

We found no human data on a Selank alcohol interaction. The rodent studies above gave Selank alongside alcohol to study alcohol’s effects ^[6][17], which is not the same as testing safety. Asking whether Selank is safe also means asking what is in the vial: a Belgian medicines laboratory identified Selank and Semax in seized preparations sold online ^[19]. See how to spot a fake peptide supplier.

Selank vs Semax is the most common comparison. Both are Russian heptapeptides from overlapping research groups and both end in Pro-Gly-Pro, but they start from different natural molecules. Selank is built on tuftsin, an immune peptide. Semax is built on the 4-7 fragment of adrenocorticotropic hormone (ACTH) ^[20]. Our Semax vs selank comparison sets the two side by side.

Their registered uses differ. Selank is an over-the-counter anxiolytic in 0.15% drops ^[9]. Semax is a prescription nootropic in 0.1% drops, and its Russian label lists disorders accompanied by anxiety among its contraindications ^[20]. In human serum, both inhibited enkephalin-degrading enzymes, Semax at about 10 µM and Selank at about 20 µM ^[11]. In the one study that gave each to healthy volunteers against placebo, they had both shared and distinct effects on amygdala connectivity ^[13]. No trial has compared them head to head on anxiety, attention or memory.

Semax and Selank nasal spray blends, and “Semax and Selank dosage charts”, are widely sold. We found no published study in people or animals that tested the two given together; the studies that included both gave them separately ^[13]. The combination has therefore not been studied for effect or safety, and the Semax label’s contraindication in disorders accompanied by anxiety ^[20] sits awkwardly with a product marketed for anxiety. Blend dosing charts are not based on research.

The Russian product information states that plasma levels fall progressively over 5 to 5.5 minutes after nasal dosing, that no metabolites are detected after nasal use, and that neither Selank nor its breakdown products appear in 24-hour urine because tissue enzymes break it down quickly ^[9]. A Russian laboratory study using radioactively labelled Selank identified shorter fragments, including the five-amino-acid TKPRP, as the main breakdown products in plasma ^[21]. We found no published human Selank half-life figure beyond the label. The one-week persistence of the anti-anxiety effect in the 2014 study ^[3] suggests the effect, if real, outlasts the peptide in blood.

In Russia, Selank nasal drops 0.15% are registered (registration ЛП-№(010951)-(РГ-RU), July 2025) with Peptogen as manufacturer, classed as an anxiolytic and sold without a prescription ^[9]. We found no marketing authorisation in the UK, US, Canada, Australia or New Zealand. See our legal status overview and the UK and US pages.

Is Selank FDA approved? No. It is not an approved drug in the US, and the FDA’s 2026 compounding list places it in a “nominated but withdrawn” group, which is not an authorisation ^[10]. For other markets, see the Australian legal status page.

Research-grade Selank is usually sold as a freeze-dried powder or pre-made nasal spray. See our guides to storing peptides and bacteriostatic water for general handling.

You can compare prices, learn how to read a COA, and see which vendors are third-party tested suppliers.

For Selank UK availability, see the UK Selank price listings; for Selank nasal spray in Australia, see the Australian Selank listings and note that Australian import rules differ. Listings are not a statement that any product is legal to buy or suitable to use. Our methodology explains how suppliers are scored.