Product description
What is Selank?
Selank (Thr-Lys-Pro-Arg-Pro-Gly-Pro) is a synthetic heptapeptide developed at the Institute of Molecular Genetics of the Russian Academy of Sciences in cooperation with the Institute of Pharmacology. W.W. Zakusowa. The peptide is a modified analogue of naturally occurring tuftsin - a tetrapeptide fragment (Thr-Lys-Pro-Arg) of the heavy chain of human immunoglobulin G (IgG).
Like Semax, Selank has been modified with the addition of the C-terminal tripeptide Pro-Gly-Pro (PGP), which increases metabolic stability and prolongs the duration of action. While native tuftsin has mainly immunomodulatory functions, the modified Selank analogue also exhibits pronounced anxiolytic and nootropic properties.
In Russia, Selank is a registered drug used as an anxiolytic and adaptogen. The peptide is available in the form of an intranasal solution (0.15%) and has effects comparable to benzodiazepines, but without their typical side effects (sedation, memory disorders, addiction).
Mechanism of action
The mechanism of action of Selank is multidirectional and includes modulation of the GABAergic system, influence on monoamine neurotransmitters and immunomodulatory effects:
GABA_A receptor modulation – Selank acts as a positive allosteric modulator of GABA_A receptors, increasing [³H]GABA binding in a concentration-dependent manner. This mechanism is similar to the action of classic benzodiazepines, but Selank does not bind to the same sites as diazepam - it can block the modulatory effects of diazepam and olanzapine, which suggests partial overlap, but not identity of the binding sites.
Effects on the serotonergic and dopaminergic systems – Selank normalizes serotonin and dopamine levels in the brain, which may contribute to its antidepressant and mood-stabilizing effects. Studies have shown activation of the expression of the Drd5 gene (dopamine D5 receptor) only by Selank, which may be related to learning and memory processes.
Boost BDNF – Like Semax, Selank increases the expression of brain-derived neurotrophic factor (BDNF), which supports neuroplasticity and neural regeneration.
Modulation of the enkephalinergic system – Selank inhibits enzymes that degrade enkephalins (endogenous opioid peptides), which increases their level and may contribute to anti-anxiety effects and mood improvement. In clinical trials, decreased levels of tau(1/2) leu-enkephalin were observed in patients with GAD and neurasthenia, which increased during treatment with Selank.
Immunomodulatory effect – As a tuftsin analogue, Selank retains immunomodulatory properties, influencing the gene expression of chemokines, cytokines and their receptors. The peptide inhibits pro-inflammatory cytokines (IL-6, TNF-α) and may support the immune response.
Regulation of GABAergic gene expression – Transcriptomic studies have shown that Selank affects the expression of genes encoding GABA receptor subunits, GABA transporters and ion channels related to GABAergic neurotransmission. After Selank administration, activation of Slc6a13 (GAT-2 transporter) expression was observed, suggesting an alternative pathway of action on the peripheral distribution of GABA.
Directions of scientific research
Selank is the subject of clinical and preclinical research, mainly in Russia, in the fields of anxiety disorders, cognitive functions and immunomodulation.
Research in anxiety disorders
The pivotal clinical trial by Zozuli et al. (2008) compared Selank with medazepam (a benzodiazepine) in 62 patients with generalized anxiety disorder (GAD) and neurasthenia. The results showed:
- Comparable anxiolytic effectiveness of Selank and medazepam
- Additional antiasthenic and psychostimulant effects of Selank (lack in medazepam)
- Increase in enkephalin activity correlating with reduction of anxiety
- Stronger positive correlations with the level of anxiety during Selank treatment
Studies on animal models of anxiety
In studies on inbred Balb/c mice (genetically high level of anxiety, "passive" type of stress reaction) and C57BL/6 (low level of anxiety, "active" type), Selank was administered intraperitoneally at doses of 200-3000 µg/kg prevented the manifestations of anxiety in the Balb/c strain, without changing the behavior in C57BL/6. The effect was comparable to that of low doses of benzodiazepines, but without the inhibitory effect on behavior even at high doses.
Research under conditions of chronic stress
The study by Kasian et al. (2017) assessed the effects of Selank and diazepam in rats under chronic unpredictable mild stress (UCMS) using the elevated plus maze test. The results showed:
- The course of administering the substance itself (without stress) increased anxiety, but the changes after Selank were less severe
- Individual administration of Selank was most effective in reducing elevated anxiety
- The diazepam + Selank combination was most effective in the UCMS setting
- Synergistic enhancement of the anxiolytic effect when administered together
Nootropic research
Selank has nootropic effects, improving learning and memory processes. In studies on rats, the peptide increased cognitive motivation and the number of conditioned avoidance responses. The mechanism includes effects on the noradrenergic and dopaminergic systems (D5 receptor).
Immunological tests
Due to its origin from tuftsin, Selank is being tested for its immunomodulatory effects. Studies have shown that the peptide (and its fragments, including Gly-Pro) affects the expression of genes for chemokines, cytokines and their receptors in the spleen of mice. Gly-Pro has been proposed as a minimal fragment of Selank with antiviral activity (pharmacophore).
Molecular mechanism studies
Transcriptomic analysis in the IMR-32 neuroblastoma line compared the effects of Selank, GABA, and olanzapine on the expression of 84 genes related to the GABAergic system and neurotransmission. The results confirmed that the molecular mechanism of Selank is related to the GABAergic system, although it is not identical to the action of GABA or olanzapine.
Scientific context
Selank represents a new approach to the pharmacotherapy of anxiety disorders - a regulatory peptide with a mechanism of action similar to benzodiazepines, but without their key drawbacks: sedation, memory disorders, tolerance and addiction.
Comparison with classic anxiolytics:
- Benzodiazepines (diazepam, medazepam) – quick action, but sedation, amnesia, addiction, withdrawal symptoms
- SSRI (sertraline, escitalopram) – no sedation or addiction, but delayed onset of action (2-4 weeks), sexual symptoms
- Selank – quick action, no sedation or addiction, additional nootropic and immunomodulatory effects
Selank and Semax are often compared as the two main Russian neurotropic peptides:
- Semax (ACTH analogue) – mainly neuroprotection and cognitive functions through the BDNF system
- Selank (tuftsin analogue) – mainly anxiolytic effect via the GABAergic system
In research practice, both peptides are sometimes used together to obtain complementary effects on cognitive function and mood regulation.
Research safety profile
Selank has demonstrated an exceptionally favorable safety profile in published studies:
Key security features:
- No sedation or impaired motor coordination
- No addiction or tolerance
- No withdrawal symptoms
- No memory impairment (unlike benzodiazepines)
- No effect on cognitive and motor skills
Reported side effects (rare and mild):
- Fatigue (occasional)
- Dizziness (rare)
- Local irritation of the nasal mucosa
Potential interactions:
- Selank may modify the action of benzodiazepines (studies indicate that the effect is enhanced when administered together with diazepam)
- No significant interactions with other drugs in available data
As with Semax, most data comes from Russian studies, and international validation and long-term safety data are limited.
Bibliography - latest scientific research
- Zozulia AA, Neznamov GG, Siuniakov TS, 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. PubMed
- Volkova A, Shadrina M, Kolomin T, et al. Selank Administration Affects the Expression of Some Genes Involved in GABAergic Neurotransmission. Front Pharmacol. 2016;7:31. PMC
- Kasian A, Kolomin T, Andreeva L, 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. PMC
- Filatova E, Kasian A, Kolomin T, et al. GABA, Selank, and Olanzapine Affect the Expression of Genes Involved in GABAergic Neurotransmission in IMR-32 Cells. Front Pharmacol. 2017;8:89. Frontiers
- Seredenin SB, Kozlovskaia MM, Blednov IuA, et al. The anxiolytic action of an analog of the endogenous peptide tuftsin on inbred mice with different phenotypes of the emotional stress reaction. Zh Vyssh Nerv Deiat Im I P Pavlova. 1998;48(1):153-160. PubMed
- V’yunova TV, Andreeva LA, Shevchenko KV, et al. Peptide-based Anxiolytics: The Molecular Aspects of Heptapeptide Selank Biological Activity. Protein Pept Lett. 2018;25(10):914-923. PubMed
- Kolomin TA, Shadrina MI, Agniullin YV, et al. Transcriptomic response of rat hippocampus and spleen cells to single and chronic administration of the peptide Selank. Dokl Biochem Biophys. 2010;430:5-6. PubMed
- Kozlovskii II, Danchev ND. The optimizing action of the synthetic peptide Selank on a conditioned active avoidance reflex in rats. Neurosci Behav Physiol. 2002;32(6):639-643. PubMed
- Semenova TP, Kozlovskaya MM, Zuikov AV, et al. Use of Selank to correct measures of integrative brain activity and biogenic amine levels in adult rats resulting from antenatal hypoxia. Neurosci Behav Physiol. 2008;38(3):203-207. PubMed
- Kolomin T, Morozova M, Volkova A, et al. The temporary dynamics of inflammation-related genes expression under tuftsin analog Selank action. Mol Immunol. 2014;58(1):50-55. PubMed