Selank

What it is

Selank is a synthetic seven-amino-acid peptide (Thr-Lys-Pro-Arg-Pro-Gly-Pro) developed at the Institute of Molecular Genetics of the Russian Academy of Sciences. Its first four amino acids are the sequence of tuftsin, a naturally occurring immune-active tetrapeptide, followed by the Pro-Gly-Pro tripeptide also used in its sibling peptide Semax. It is manufactured in Russia as nasal drops, and most of its published research comes from Russian laboratories and clinics, much of it in Russian-language journals.

Mechanism of action

How Selank acts is not settled, and several pathways have been proposed by the same network of Russian groups. One concerns the body's enkephalins, short opioid peptides that are quickly broken down in the blood. Kost et al. (2001) reported that Selank inhibited enkephalin-degrading enzymes in human serum in a dose-dependent way, with an IC50 of 20 µM (10 µM for Semax), and Zozulia et al. (2008) reported that the half-life of leu-enkephalin in blood, low in patients with anxiety disorders, rose during Selank treatment. A second line concerns GABA signaling: Volkova et al. (2016) found overlapping gene-expression changes in the rat frontal cortex after Selank or GABA and suggested allosteric modulation of the GABAergic system. A third, reflecting its tuftsin origin, concerns immune signaling, with reported effects on IL-6 expression and the balance of Th1 and Th2 cytokines (Uchakina et al., 2008). None of these has been confirmed as the main mechanism.

What it’s most studied for

Selank research centers on anxiety. Russian clinical groups have studied it in adults with generalized anxiety disorder, neurasthenia and related anxiety-phobic and somatoform disorders, usually alongside or in comparison with benzodiazepine tranquilizers such as medazepam and phenazepam, which matches its registered use in Russia. The same patient groups have been used to examine immune markers and enkephalin breakdown. In rats, researchers have used it in models of anxiety during alcohol withdrawal and chronic mild stress, and in gene-expression studies of the frontal cortex. The shared rationale is that a short, stabilized peptide might reduce anxiety without the sedation and memory effects associated with benzodiazepines, a question the published studies have not settled.

Notable findings

Each finding carries the species or population it was observed in and the dose that study used. Doses are reported as research context, exactly as published. They are not guidance.

Study quality

Human evidence for Selank is limited to small clinical studies from Russian groups, and no randomized, placebo-controlled trial was identified for this summary. The two efficacy studies cited here enrolled 62 and 70 adults with anxiety disorders and compared Selank with, or added it to, a benzodiazepine; their English abstracts give qualitative results without effect sizes, doses or details on randomization and blinding. The preclinical work consists of rat studies of alcohol withdrawal, chronic mild stress (Kasian et al., 2017) and cortical gene expression, plus in vitro enzyme and blood cell experiments. Much of the research comes from one network: N. V. Kost, O. Iu. Sokolov and N. F. Myasoedov co-authored several of the cited papers, and independent replication is sparse. On safety, the abstracts do not report adverse-event rates for Selank itself; Medvedev et al. (2015) reported fewer benzodiazepine side effects when Selank was added.

References

1. 1
   Zozulia AA, Neznamov GG, Siuniakov TS, et al. (2008). [Efficacy and possible mechanisms of action of a new peptide anxiolytic selank in the therapy of generalized anxiety disorders and neurasthenia]. Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova. PMID 18454096
2. 2
   Medvedev VE, Tereshchenko ON, Kost NV, et al. (2015). [Optimization of the treatment of anxiety disorders with selank]. Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova. DOI 10.17116/jnevro20151156133-40
3. 3
   Uchakina ON, Uchakin PN, Miasoedov NF, et al. (2008). [Immunomodulatory effects of selank in patients with anxiety-asthenic disorders]. Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova. PMID 18577961
4. 4
   Kolik LG, Nadorova AV, Kozlovskaya MM (2014). Efficacy of peptide anxiolytic selank during modeling of withdrawal syndrome in rats with stable alcoholic motivation. Bulletin of Experimental Biology and Medicine. PMID 24913576
5. 5
   Volkova A, Shadrina M, Kolomin T, et al. (2016). Selank administration affects the expression of some genes involved in GABAergic neurotransmission. Frontiers in Pharmacology. DOI 10.3389/fphar.2016.00031
6. 6
   Kost NV, Sokolov OI, Gabaeva MV, et al. (2001). [Semax and selank inhibit the enkephalin-degrading enzymes from human serum]. Bioorganicheskaia Khimiia. PMID 11443939
7. 7
   Kasian A, Kolomin T, Andreeva L, et al. (2017). Peptide Selank enhances the effect of diazepam in reducing anxiety in unpredictable chronic mild stress conditions in rats. Behavioural Neurology. PMID 28280289
8. 8
   Vidal Russia drug reference (2025). Selank (Селанк®) nasal drops 0.15%: registration and product information. Vidal.ru.