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Draft entry. Written from the cited papers but not yet reviewed by a person. Check the references before relying on any claim.
Peptide· Anxiolytic

Selank

also Thr-Lys-Pro-Arg-Pro-Gly-Pro · TP-7 · Selanc

Selank is a synthetic heptapeptide (Thr-Lys-Pro-Arg-Pro-Gly-Pro) described as an analogue of tuftsin [1]. It is studied as an anxiolytic. In Russian clinical studies of generalised anxiety and related disorders, it matched the benzodiazepine medazepam on anxiety [2], and adding it to phenazepam reduced phenazepam's side effects [3]. Proposed mechanisms include slowing enkephalin breakdown and modulating GABA-A receptors [4][5].

A benzodiazepine-like anxiolytic peptide with encouraging but small, Russian-only clinical studies; treat the "no side effects" reputation as untested rather than proven.

2D chemical structure of Selank
C33H57N11O9751.9 g/molCID 11765600 ↗
Early human trials11 papers · 2001–2022 · 7 journals · 6 in humans
  • meta-analysis
  • RCT
  • trial
  • observational
  • preclinical / case
  • review / patent / other
  • retracted
2001 · observational · The inhibitory effect of Selank on enkephalin-degrading enzymes as a possible mechanism of its anxiolytic activity.2001 · preclinical · [Semax and selank inhibit the enkephalin-degrading enzymes from human serum]].2008 · RCT · [Efficacy and possible mechanisms of action of a new peptide anxiolytic selank in the therapy of generalized anxiety disorders and neurasthenia].2008 · clinical trial · [Immunomodulatory effects of selank in patients with anxiety-asthenic disorders].2014 · clinical trial · [A comparison of the anxiolytic effect and tolerability of selank and phenazepam in the treatment of anxiety disorders].2015 · RCT · [Optimization of the treatment of anxiety disorders with selank].2017 · preclinical · GABA, Selank, and Olanzapine Affect the Expression of Genes Involved in GABAergic Neurotransmission in IMR-32 Cells.2017 · preclinical · Peptide Selank Enhances the Effect of Diazepam in Reducing Anxiety in Unpredictable Chronic Mild Stress Conditions in Rats.2018 · preclinical · Peptide-based Anxiolytics: The Molecular Aspects of Heptapeptide Selank Biological Activity.2020 · clinical trial · Functional Connectomic Approach to Studying Selank and Semax Effects.2022 · preclinical · Selank, a Peptide Analog of Tuftsin, Attenuates Aversive Signs of Morphine Withdrawal in Rats.
in its favour
  • + Matched medazepam on anxiety in generalised anxiety disorder
  • + Reduced phenazepam side effects when added to it
  • + Anxiety relief lasted a week after stopping in one study
watch for
  • − Clinical studies are small and published only in Russian
  • − Mechanism is still being worked out
  • − Not studied in long-term use

Overview

A note on the evidence. Selank's clinical studies are published in Russian journals. This entry relies on the English abstracts that PubMed indexes, and papers without one are not cited. Russian-language references are marked in the reference list.

Three clinical studies compare Selank with benzodiazepines:

  • Generalised anxiety and neurasthenia (62 patients). Selank and medazepam had similar anxiolytic effects. Selank also had anti-fatigue and mildly stimulating effects [2].
  • Phobic, anxiety and somatoform disorders (60 patients). In a study comparing it with phenazepam, Selank showed a pronounced anxiolytic and mild nootropic effect that lasted a week after the last dose [6].
  • Added to phenazepam. Adding Selank made phenazepam work sooner. It also reduced phenazepam's side effects, including memory problems, sedation, fatigue and sexual problems, both during treatment and after withdrawal [3].

In 52 healthy volunteers, a single dose changed resting-state connectivity between the right amygdala and temporal cortex on fMRI compared with placebo [7].

Mechanism

Two mechanisms have the most support. First, Selank inhibits the enzymes that break down enkephalins, the body's own opioid peptides. People with generalised anxiety showed faster enkephalin breakdown than normal. Selank inhibited that breakdown in plasma more potently than classic peptidase inhibitors [4]. During treatment, enkephalin half-life rose in patients with generalised anxiety [2].

Second, Selank acts on GABA-A receptors. Binding studies found it to be a positive allosteric modulator of GABA binding, and it interacts with benzodiazepine binding in a complex, non-additive way [5]. In a neuroblastoma cell line it did not change GABA-system gene expression on its own, but it altered GABA's effects [8]. In rats, Selank and diazepam together worked best against anxiety under chronic stress [9].

Direct targetswhat the molecule itself binds or acts on
  • Enkephalin-degrading enzymesblocks
    inhibited breakdown of enkephalin in human plasma (IC50 about 15 µM) [4][10]
    moderate
  • GABA-A receptorsmodulates
    acted as a positive allosteric modulator of GABA binding [5]
    unclear
Downstreamconsequences of that action, not targets of their own
  • Th1/Th2 cytokine balancemodulates
    shifted serum cytokines in patients with anxiety disorders over 14 days of treatment [11]
    weak

Safety

risks and cautions, not medical advice

Studies describe Selank as well tolerated and free of the side effects typical of most anxiolytics [4], and it reduced phenazepam's side effects when added to it [3]. Those statements come from small, short studies without detailed adverse-event reporting in the indexed abstracts.

Adverse effects
reported, not universal
  • Reported as well tolerated in small studies [4]
Cautions
who should think twice
  • Do not combine with benzodiazepines without medical advice [5]
  • Products sold online are unregulated and unverified
Limits of the evidence
what has not been shown
  • The clinical studies are small, published in Russian, and compare against benzodiazepines rather than placebo [2][6]
  • Mechanism data come from plasma enzymes, cell lines and rats [4][8][9]
  • No long-term safety studies are indexed in English

Interactions

documented pairs only, not exhaustive

Selank has been studied as an add-on to the benzodiazepine phenazepam in patients [3] and alongside diazepam in rats [9]. Its effects on GABA binding with benzodiazepines are not simply additive [5]. Anyone on a benzodiazepine should not add it without medical advice.

  • Semax
    compatible
    No interaction documented; the two were given separately, not together, in one volunteer study [7]

FAQ

Is Selank as effective as a benzodiazepine?
In a small Russian study it matched medazepam on anxiety [2]. No large placebo-controlled trial is indexed in English.
How does Selank work?
It slows the breakdown of enkephalins [4] and modulates GABA-A receptor binding [5].

References

entry last reviewed 2026-09-18
  1. [1]
    Selank, a Peptide Analog of Tuftsin, Attenuates Aversive Signs of Morphine Withdrawal in Rats.
    Konstantinopolsky MA, Chernyakova IV, Kolik LGBull Exp Biol Med 2022preclinical · animalPMID 36322304◌ unreviewed
  2. [2]
    [Efficacy and possible mechanisms of action of a new peptide anxiolytic selank in the therapy of generalized anxiety disorders and neurasthenia].
    Zozulia AA, Neznamov GG, Siuniakov TS et al.Zh Nevrol Psikhiatr Im S S Korsakova 2008RCT · humanPMID 18454096in Russian◌ unreviewed
  3. [3]
    [Optimization of the treatment of anxiety disorders with selank].
    Medvedev VE, Tereshchenko ON, Kost NV et al.Zh Nevrol Psikhiatr Im S S Korsakova 2015RCT · humanPMID 26356395in Russian◌ unreviewed
  4. [4]
    The inhibitory effect of Selank on enkephalin-degrading enzymes as a possible mechanism of its anxiolytic activity.
    Zozulya AA, Kost NV, Yu Sokolov O et al.Bull Exp Biol Med 2001observational · humanPMID 11550013◌ unreviewed
  5. [5]
    Peptide-based Anxiolytics: The Molecular Aspects of Heptapeptide Selank Biological Activity.
    Vyunova TV, Andreeva L, Shevchenko K et al.Protein Pept Lett 2018preclinicalPMID 30255741◌ unreviewed
  6. [6]
    [A comparison of the anxiolytic effect and tolerability of selank and phenazepam in the treatment of anxiety disorders].
    Medvedev VE, Tereshchenko ON, Israelian AIu et al.Zh Nevrol Psikhiatr Im S S Korsakova 2014clinical trial · humanPMID 25176261in Russian◌ unreviewed
  7. [7]
    Functional Connectomic Approach to Studying Selank and Semax Effects.
    Panikratova YR, Lebedeva IS, Sokolov OY et al.Dokl Biol Sci 2020clinical trial · humanPMID 32342318◌ unreviewed
  8. [8]
    GABA, Selank, and Olanzapine Affect the Expression of Genes Involved in GABAergic Neurotransmission in IMR-32 Cells.
    Filatova E, Kasian A, Kolomin T et al.Front Pharmacol 2017preclinical · cellPMID 28293190◌ unreviewed
  9. [9]
    Peptide Selank Enhances the Effect of Diazepam in Reducing Anxiety in Unpredictable Chronic Mild Stress Conditions in Rats.
    Kasian A, Kolomin T, Andreeva L et al.Behav Neurol 2017preclinical · animalPMID 28280289◌ unreviewed
  10. [10]
    [Semax and selank inhibit the enkephalin-degrading enzymes from human serum]].
    Kost NV, Sokolov OIu, Gabaeva MV et al.Bioorg Khim 2001preclinicalPMID 11443939in Russian◌ unreviewed
  11. [11]
    [Immunomodulatory effects of selank in patients with anxiety-asthenic disorders].
    Uchakina ON, Uchakin PN, Miasoedov NF et al.Zh Nevrol Psikhiatr Im S S Korsakova 2008clinical trial · humanPMID 18577961in Russian◌ unreviewed