Selank
Russia's tuftsin-based anxiety drops: small trials against benzodiazepines, rodent GABA data, no trials outside Russia
Selank is seven amino acids: tuftsin, an immune-system peptide the body makes, with a Pro-Gly-Pro tail added. Russia approved it for anxiety, and the clinical studies behind it are Russian, small, and compare it with benzodiazepines rather than placebo. The animal work points at GABA receptors and at enzymes that break down enkephalins. Nobody outside Russia has tested it in patients, and a 2021 US review called it poorly studied.
What is it?
Selank is a heptapeptide, Thr-Lys-Pro-Arg-Pro-Gly-Pro. The first four residues are tuftsin, an immunomodulatory peptide the body makes; the Pro-Gly-Pro tail is the same one grafted onto semax, and several Russian authors appear on papers about both. It is approved in Russia for anxiety and given there as nasal drops, and the human research on it comes almost entirely from Russian groups.
The clinical studies are small and measure selank against benzodiazepines. In 62 patients with generalised anxiety disorder or neurasthenia, it matched medazepam's anti-anxiety effect and added anti-fatigue and stimulant-like effects. In 60 patients with phobic, anxiety and somatoform disorders, the anti-anxiety effect lasted a week after the last dose. Added to phenazepam in 40 patients, it brought the benzodiazepine's benefit on sooner and reduced its side effects, from memory problems to sedation, including after withdrawal. None of these abstracts describes a placebo group or blinding.
The mechanism work is mostly in rats and mice. Selank shifted the expression of 45 of 84 neurotransmission genes in rat frontal cortex within an hour, in a pattern that tracked GABA's own. Injected into anxious mice it raised GABA-receptor binding, though given nasally it did not. In blood from patients it slowed the breakdown of enkephalins, the body's own opioid peptides, whose half-life was shortened in generalised anxiety. And single doses eased the anxiety of alcohol and morphine withdrawal in rats.
What is missing is any trial outside Russia, any placebo-controlled treatment trial in our evidence set, and any study of long-term safety or dependence. A 2021 review in the Journal of Clinical Pharmacology grouped selank with phenibut as poorly studied Russian drugs with GABA-related mechanisms being sold to US consumers as dietary supplements, and argued that such agents should be tested for abuse potential before the public can buy them. It is not FDA-approved and is on no US compounding list.
Mechanism of Action
The abstracts describe three routes to an anti-anxiety effect and one immune thread. All were measured in animals, in cells or in patients' blood, and none has been shown to drive the clinical results.
The enkephalin step is a test-tube result and the gene changes are from rats. The patient trials compared it with benzodiazepines rather than placebo.
Each step is tagged with where it was shown. A dashed red arrow marks a link the evidence does not establish.
The pathway in words
- Selank. A seven-amino-acid peptide built on tuftsin, an endogenous immune peptide, given as nasal drops in Russia. Shown in: animals. Source: PubMed 31625062.
- Slower enkephalin breakdown. In human plasma it inhibited the breakdown of enkephalins in a dose-dependent way (IC50 15 µM). Shown in: lab. Source: PubMed 11550013.
- GABA-like gene changes. In rat frontal cortex, 45 of 84 neurotransmission genes changed an hour after selank, in a pattern correlated with GABA's effects. Shown in: animals. Source: PubMed 26924987.
- Anxiety in patients. In 62 patients with generalised anxiety or neurasthenia, its anti-anxiety effect matched the benzodiazepine medazepam's. Shown in: people. Source: PubMed 18454096.
- no placebo-controlled trial reported. Better than placebo. The anxiety trials here compared selank with benzodiazepines, not placebo, and a US review calls it poorly studied. Shown in: review. Source: PubMed 34396551.
GABA signalling
One hour after a 300 µg/kg dose in rats, 45 of 84 genes involved in neurotransmission had changed expression in the frontal cortex, and 22 had at three hours, in a pattern that correlated with the changes GABA itself produced. In anxious mice, five days of injected selank raised GABA-receptor binding sites in the frontal cortex by 38%; given nasally, it left GABA receptors alone and raised NMDA-receptor binding in the hippocampus by 23%.
Protecting enkephalins
Patients with generalised anxiety had a shortened enkephalin half-life and lower total enkephalinase activity in their blood, unlike patients with panic disorder or agoraphobia. Selank inhibited the breakdown of plasma enkephalin with a half-maximal concentration of 15 µM, more potently than the peptidase inhibitors bacitracin and puromycin.
Withdrawal and memory in rats
Single 0.3 mg/kg injections abolished anxiety during alcohol withdrawal without changing how much the rats drank, and cut a morphine-withdrawal score by 39.6%, against 49.3% for diazepam. A week of daily doses prevented alcohol-related memory problems and blocked an alcohol-driven rise in BDNF in the hippocampus and frontal cortex.
Immune signalling
In blood cells from patients with depression, selank at 10⁻⁷ M suppressed IL-6 gene expression, although IL-6 protein in the same cultures rose. In patients with generalised anxiety or neurasthenia, 14 days of treatment shifted the serum balance of Th1 and Th2 cytokines.
Published Research
Our evidence set holds 36 papers on selank, 32 of them naming it in the title. The human studies are Russian and small and compare selank with benzodiazepines rather than placebo; the animal work outnumbers the clinical. The 14 cards below cover both, plus a 2021 US review that is sceptical of the whole category. Several of the clinical papers are in Russian, and their cards draw on the English abstracts.
Selank vs medazepam in generalised anxiety
Sixty-two patients with generalised anxiety disorder or neurasthenia took selank (30) or medazepam (32), rated on the Hamilton, Zung and CGI scales. Anti-anxiety effects were similar, and selank also had anti-fatigue and stimulant-like effects. Patients started with a shortened leu-enkephalin half-life that tracked the duration and severity of their illness, and it lengthened on selank, mainly in generalised anxiety.
Selank vs phenazepam
In 60 patients with phobic-anxiety and somatoform disorders, selank showed pronounced anti-anxiety and mild nootropic effects, and improved quality of life. The anti-anxiety effect lasted a week after the last dose. The abstract compares selank with phenazepam but reports no figures for the comparison.
Added to phenazepam
Seventy patients with anxiety-spectrum disorders took phenazepam alone (30) or phenazepam with selank (40). With selank, phenazepam's benefit on the Hamilton scale arrived sooner, and its side effects (attention and memory problems, fatigue, sedation, longer sleep, sexual problems, emotional blunting and dizziness on standing) fell, both during treatment and after the benzodiazepine was withdrawn.
Cytokines in anxious patients
In cultured blood cells from patients with depression, selank at 10⁻⁷ M completely suppressed IL-6 gene expression, while IL-6 concentration in the same cultures rose; healthy controls' cells did not respond. Patients with generalised anxiety or neurasthenia who took selank for 14 days showed shifts in the serum Th1/Th2 cytokine balance.
Enkephalins in anxiety disorders
Patients with generalised anxiety had a markedly shortened enkephalin half-life and lower total enkephalinase activity in their blood; patients with panic disorder or agoraphobia did not. Selank inhibited the breakdown of plasma enkephalin in a dose-dependent way (IC50 15 µM), more potently than bacitracin or puromycin.
Brain connectivity in healthy volunteers
Fifty-two healthy people had resting-state fMRI before and 5 and 20 minutes after a dose of selank, semax or placebo. The groups differed in connectivity between the right amygdala and regions of the right temporal cortex, and the authors describe both shared and drug-specific effects of the two peptides.
A US view of GABA-acting drugs
This review of GABA-acting sedatives calls phenibut and selank poorly studied Russian drugs with GABAergic mechanisms that are sold to US consumers as dietary supplements, notes rising poison-centre calls about phenibut, and argues that new GABA-acting agents should be evaluated for abuse potential before public access.
GABA-like gene changes in rat cortex
Rats received selank or GABA at 300 µg/kg, and 84 neurotransmission genes were measured in the frontal cortex. Forty-five changed expression after one hour and 22 after three, and the changes after selank correlated positively with those after GABA.
Nasal vs injected, in mice
Mice received 300 µg/kg a day for five days, nasally or by injection. Anti-anxiety and nootropic effects appeared only in BALB/c mice, which start out more anxious. Injected selank raised GABA-receptor binding sites in the frontal cortex by 38%; nasal selank raised NMDA-receptor binding in the hippocampus by 23% and left GABA receptors unchanged.
With diazepam, under chronic stress
In rats, a course of selank or diazepam alone shifted anxiety measures for the worse even without stress, less so with selank, and selank alone best reversed that rise. Under unpredictable chronic mild stress, selank combined with diazepam was the most effective at reducing anxiety.
Alcohol withdrawal in rats
In rats that had drunk 10% ethanol as their only fluid for 24 weeks, a single 0.3 mg/kg injection of selank eliminated withdrawal anxiety in two behavioural tests and prevented mechanical allodynia, without changing how much ethanol the animals chose to drink.
Morphine withdrawal in rats
A single 0.3 mg/kg injection cut the total morphine-withdrawal score by 39.6% and raised the tactile sensitivity threshold ninefold in morphine-dependent rats. Diazepam at 2 mg/kg did slightly better: a 49.3% reduction and a 13-fold rise.
Alcohol and memory in rats
Rats given 10% ethanol as their only fluid for 30 weeks received selank at 0.3 mg/kg a day for seven days. It prevented the memory and attention problems that developed during withdrawal, improved object recognition in rats never given alcohol, and blocked an alcohol-induced rise in BDNF in the hippocampus and frontal cortex.
Nasal selank in monkeys
In monkeys with experimentally induced neurosis, intranasal selank produced long-lasting changes in behaviour: fear and aggression disappeared, exploration increased, and disturbed memory and homeostatic measures were compensated, whatever the type of neurotic disturbance.
What people say, and what was measured
Selank is sold as an anxiolytic without sedation, and unusually for this site it has comparative trials against actual benzodiazepines. They are small, Russian-language and from overlapping groups, which is the limit worth stating alongside the result.
It treats anxiety as well as a benzodiazepine, without the sedation or dependence.
Heard in: Zhurnal Nevrologii i Psikhiatrii, the comparative trials of selank against benzodiazepines that the claim rests on (read October 1, 2026). Source
Two comparisons exist: selank against medazepam in 62 patients with generalised anxiety disorder and neurasthenia, and against phenazepam in 60 patients with phobic-anxiety and somatoform disorders. Both are small, open and Russian-language, and no trial outside that literature has reproduced them. PMID: 18454096, 25176261, 26356395
Tested in people; mixedIt works by boosting the body's own enkephalins, so the effect is natural.
Heard in: Grey Peptides listing review, October 1, 2026: listings describe it as working through endogenous opioid peptides. Sellers are not named.
The mechanism was measured: selank inhibits the enzymes that degrade enkephalins, and in the anxiety trial patients had a shortened enkephalin half-life that tracked symptom severity. That is a plausible mechanism, not a safety argument, and gene-expression work on GABA signalling is in rats. PMID: 11550013, 18454096, 26924987
Measured, never givenIt helps with alcohol and opioid withdrawal.
Heard in: Grey Peptides listing review, October 1, 2026: listings mention withdrawal and craving. Sellers are not named.
All in rats: attenuating aversive signs of morphine withdrawal, protecting against ethanol-induced memory impairment, and efficacy during modelled withdrawal syndrome. No human study of withdrawal appears on this entry. PMID: 36322304, 31625062, 24913576
Shown in animals or cells onlyThe nasal spray works as well as injection.
Heard in: Grey Peptides listing review, October 1, 2026: listings sell it mainly as a nasal spray. Sellers are not named.
A rat study compared intranasal and intraperitoneal routes directly, which is the only route comparison here. In people, the Russian trials used the intranasal form, so the human evidence such as it is describes that route. PMID: 29787664, 18454096
Shown in animals or cells onlyEach claim is quoted from where it is said, never from a seller, and checked as of October 1, 2026 against the studies listed below.
Dosing Data
Russian approval comes with a nasal-drop regimen, which our dataset records; the clinical abstracts on this page do not state their doses. The animal doses are per kilogram and mostly injected, which is not how people use the drug.
Educational information, not medical advice. Each dose above is tagged with its source: an approved label, a published human study, animal data, or amounts reported by users. None is a recommendation for you. An unapproved compound has no established safe or effective human dose, and products sold for “research use only” are not made or tested for people. Talk to a doctor before acting on anything on this site, including before you start, stop or change any medicine or dose. Full medical disclaimer.
→ Full Selank dosage guide — the Russian nasal regimen, the injected animal doses, and what the clinical abstracts leave out.
→ Blend & Stack Calculator — Selank is also sold in multi-peptide vials; the calculator shows what each draw delivers of every component; our blends and stacks hub sets out what each mix contains and what has been studied.
Side Effects & Contraindications
Reported Side Effects
The clinical abstracts report benefits more than harms, and what they say about tolerability comes mainly from comparisons with benzodiazepines.
Contraindications & Cautions
No study set out who should avoid selank. These cautions follow from its pharmacology and from the gaps in the record.
Legal Status
Selank is approved as a medicine in Russia and in none of the other jurisdictions below. Status as of September 26, 2026.
Frequently Asked Questions
?Is selank a benzodiazepine?
No. It is a seven-amino-acid peptide, but rat studies suggest it works partly through the same GABA system: its gene-expression effects in rat cortex tracked GABA's own, and it added to diazepam's effect in stressed rats. In a Russian clinical study it matched medazepam's anti-anxiety effect.
?Has selank been tested against a placebo?
Not in any treatment study in our evidence set. The clinical abstracts compare it with benzodiazepines or add it to one. A 2020 brain-imaging study in 52 healthy volunteers had a placebo group, but it measured brain connectivity, not anxiety.
?Does selank cause dependence or withdrawal?
No study we found measured it. Russian studies report fewer side effects when selank was added to phenazepam, including after the benzodiazepine was stopped, but that is not a test of selank's own dependence potential, which a 2021 US review said should be done.
?Why is selank given as nasal drops?
That is how it is used in Russia. In mice, nasal and injected doses acted on different receptors: injection raised GABA-receptor binding in the frontal cortex, while nasal dosing raised NMDA-receptor binding in the hippocampus. No study in our evidence set measured how much reaches the human brain.
?How is selank related to semax?
Both are Russian nasal peptides ending in the same Pro-Gly-Pro tail. Semax is built on a fragment of ACTH and studied mainly for stroke and cognition; selank is built on tuftsin and approved for anxiety. A 2020 imaging study gave both to healthy volunteers and found shared and distinct effects on the connectivity of the right amygdala.
?Does selank help with alcohol or opioid withdrawal?
Only rat studies exist. Single doses abolished anxiety during alcohol withdrawal and reduced morphine-withdrawal signs by about 40%, slightly less than diazepam. No human withdrawal trial appears in our evidence set.
References
- [pubmed] Zozulia AA, et al. "[Efficacy and possible mechanisms of action of a new peptide anxiolytic selank in the therapy of generalized anxiety disorders and neurasthenia]." Zh Nevrol Psikhiatr Im S S Korsakova, 2008;108(4):38-48. PMID: 18454096.
- [pubmed] Medvedev VE, et al. "[A comparison of the anxiolytic effect and tolerability of selank and phenazepam in the treatment of anxiety disorders]." Zh Nevrol Psikhiatr Im S S Korsakova, 2014;114(7):17-22. PMID: 25176261.
- [pubmed] Medvedev VE, et al. "[Optimization of the treatment of anxiety disorders with selank]." Zh Nevrol Psikhiatr Im S S Korsakova, 2015;115(6):33-40. PMID: 26356395.
- [pubmed] Uchakina ON, et al. "[Immunomodulatory effects of selank in patients with anxiety-asthenic disorders]." Zh Nevrol Psikhiatr Im S S Korsakova, 2008;108(5):71-5. PMID: 18577961.
- [pubmed] Zozulya AA, et al. "The inhibitory effect of Selank on enkephalin-degrading enzymes as a possible mechanism of its anxiolytic activity." Bull Exp Biol Med, 2001;131(4):315-7. PMID: 11550013.
- [pubmed] Panikratova YR, et al. "Functional Connectomic Approach to Studying Selank and Semax Effects." Dokl Biol Sci, 2020;490(1):9-11. PMID: 32342318.
- [review] Doyno CR, et al. "Sedative-Hypnotic Agents That Impact Gamma-Aminobutyric Acid Receptors: Focus on Flunitrazepam, Gamma-Hydroxybutyric Acid, Phenibut, and Selank." J Clin Pharmacol, 2021;61 Suppl 2:S114-S128. PMID: 34396551.
- [pubmed] Volkova A, et al. "Selank Administration Affects the Expression of Some Genes Involved in GABAergic Neurotransmission." Front Pharmacol, 2016;7:31. PMID: 26924987.
- [pubmed] Vasil'eva EV, et al. "[COMPARISON OF PHARMACOLOGICAL EFFECTS OF HEPTAPEPTIDE SELANK AFTER INTRANASAL AND INTRAPERITONEAL ADMINISTRATION TO BALB/c AND C57BL/6 MICE.]." Eksp Klin Farmakol, 2016;79(9):3-11. PMID: 29787664.
- [pubmed] Kasian A, et al. "Peptide Selank Enhances the Effect of Diazepam in Reducing Anxiety in Unpredictable Chronic Mild Stress Conditions in Rats." Behav Neurol, 2017;2017:5091027. PMID: 28280289.
- [pubmed] Kolik LG, et al. "Efficacy of peptide anxiolytic selank during modeling of withdrawal syndrome in rats with stable alcoholic motivation." Bull Exp Biol Med, 2014;157(1):52-5. PMID: 24913576.
- [pubmed] Konstantinopolsky MA, et al. "Selank, a Peptide Analog of Tuftsin, Attenuates Aversive Signs of Morphine Withdrawal in Rats." Bull Exp Biol Med, 2022;173(6):730-733. PMID: 36322304.
- [pubmed] Kolik LG, et al. "Selank, Peptide Analogue of Tuftsin, Protects Against Ethanol-Induced Memory Impairment by Regulating of BDNF Content in the Hippocampus and Prefrontal Cortex in Rats." Bull Exp Biol Med, 2019;167(5):641-644. PMID: 31625062.
- [pubmed] "[Compensatory and antiamnestic effects of heptapeptide Selank in monkeys]." Zh Evol Biokhim Fiziol, 2008;44(3):284-90. PMID: 18727417.
- [other] Peptogen. Selank (nasal drops 0.15%), instruction for medical use, Russian registration LP-No(010951)-(RG-RU), approved by the Ministry of Health of the Russian Federation (manufacturer's copy and RLS; read September 30, 2026): adults 18 and over, 2 drops in each nostril 3 times a day for 14 days.
Sources & Citations
Every PMID on this page is PubMed-indexed and has been checked against its record. One source, a 2008 report by Zozulya and colleagues, has no PubMed record we could find. A second citation in our dataset turned out to be PMID 25176261 under a different English title, and is now cited by its PubMed record. Grey Peptides sells nothing and links to no vendor.
Medical Disclaimer: This content is for educational and informational purposes only. It is not medical advice, and nothing here is an instruction to obtain or use any compound. Talk to a licensed clinician about your own situation.