Selank for Research in Canada

What Selank is

Selank is a synthetic seven-residue peptide, Thr-Lys-Pro-Arg-Pro-Gly-Pro (TKPRPGP), built by attaching the tripeptide Pro-Gly-Pro to the C-terminus of the tetrapeptide tuftsin (Thr-Lys-Pro-Arg)^[2]. Most published work on it comes from Russian research groups, mainly in rodent models of anxiety-like behaviour, learning and stress, in cell and tissue gene-expression work, and in a small number of Russian-language clinical comparisons^{[3, 1, 16]}. It has no Health Canada, FDA or EMA approval that we could find, and a 2021 US review called it a “poorly studied Russian drug” that was being sold to US consumers as a dietary supplement^[19]. The material listed here is sold for laboratory research only.

Key facts

• Sequence: TKPRPGP, 7 amino acids; C₃₃H₅₇N₁₁O₉, 751.9 g/mol (PubChem CID 11765600); CAS 129954-34-3. Also called TP-7.
• Proposed mechanisms (animal and in-vitro): positive allosteric modulation of GABA binding in brain membranes^[1] and inhibition of enkephalin-degrading enzymes in plasma^[4].
• Short-lived in plasma: a tritium-label study found it broken down to TKPRP, TKP, RP and GP^[6].
• Evidence base: mostly rat and mouse behaviour and gene-expression studies; human data are limited to small Russian clinical studies published in Russian^{[16, 17]}.
• Batch documentation on this site: no batch-specific COA for Selank 10MG is posted in the COA library at the time of writing.

Origin and design

Selank keeps the four-residue tuftsin sequence and adds Pro-Gly-Pro; a 2006 Polish rat study described it simply as “a structure of tuftsin, to which three natural L-amino-acids Pro-Gly-Pro are attached”^[2]. A 2003 comparison of ten tuftsin-family peptides and Selank in rats and mice under conflict stress concluded that each peptide’s effect depended on its structure and on its degradation fragments^[3]. That point is borne out by the breakdown work: when Selank was labelled evenly with tritium and incubated in blood plasma, the pentapeptide TKPRP, the tripeptide TKP and the dipeptides RP and GP were the main products^[6]. Several later papers therefore tested the Gly-Pro fragment alongside the full peptide^[14].

Identity

Mechanisms studied, by model

Brain membranes and cell lines

Radioligand experiments on isolated brain-cell membranes showed Selank acting on [³H]GABA binding as a positive allosteric modulator; combined with benzodiazepines the effect was not additive, and Selank blocked the modulating action of diazepam and olanzapine, which the authors read as partly overlapping but distinct binding sites^[1]. In neuroblastoma IMR-32 cells, by contrast, Selank alone changed the mRNA level of none of 84 GABA-system and neurotransmission genes; it altered expression only when combined with GABA (largely cancelling GABA’s changes) or with olanzapine^[8].

Enkephalin breakdown

In plasma samples, Selank inhibited enkephalin-hydrolysing enzymes in a dose-dependent way and was more potent than the peptidase inhibitors bacitracin and puromycin^[4]. A mouse study then compared two strains: in BALB/c mice Selank lengthened the plasma half-life of leu-enkephalin and changed open-field behaviour, while in C57Bl/6 mice it affected neither^[5].

Rat behaviour and gene expression

In the rat frontal cortex, Selank and GABA each changed the expression of 45 of 84 neurotransmission genes one hour after administration and 22 genes at three hours, with correlated patterns between the two^[7]. Behavioural rat work has looked at the elevated plus maze under unpredictable chronic mild stress, alone and with diazepam^[9]; conditioned active-avoidance learning compared with piracetam, where the clearest effect was in rats that learned poorly at baseline^[10]; memory and hippocampal/frontal BDNF in rats given ethanol for 30 weeks^[11]; and naloxone-precipitated morphine withdrawal, where Selank reduced the withdrawal index but less than the diazepam comparator^[12].

Immune and antiviral models

Earlier transcriptome work had linked Selank to inflammatory processes, so several groups measured immune genes^[13]. In mouse spleen, a single injection changed the expression of 34 of 84 inflammation-related genes, with Bcl6 among the clearest^[13]; a follow-up tracked C3, Casp1, Il2rg and Xcr1 over the first hours and found the Gly-Pro fragment reproduced part of the pattern^[14]. Against influenza A/Aichi/2/68 (H3N2), Selank suppressed viral reproduction in cell culture when added 24 hours before inoculation and improved survival in infected mice given it on a preventive schedule, with increased interferon-alpha gene expression^[15].

Study summary

Human studies, stated plainly

Two Russian clinical papers compared Selank with a benzodiazepine: one randomised 62 patients with generalised anxiety disorder or neurasthenia to Selank or medazepam and reported similar anxiolytic scores^[16], and the other compared it with phenazepam in 60 patients with phobic-anxiety and somatoform disorders^[17]. A related study measured interleukin-6 expression and cytokine balance in patients’ blood^[18]. All three were small, were published in Russian, and have not been repeated by independent groups elsewhere; the 2021 US review cited above describes the evidence as thin^[19]. None of this makes Selank an approved or recommended product, and this page gives no dosing or administration information.

What the evidence does not show

• No large, placebo-controlled, multi-centre trial of Selank has been published in the indexed literature we searched.
• Almost all studies come from a small number of Russian research groups; independent replication is scarce.
• The mechanism is unsettled: membrane binding work points to GABA-receptor modulation^[1], yet the neuroblastoma study saw no gene-expression change from Selank alone^[8].
• Because the peptide is broken down quickly into smaller fragments^[6], effects seen in animals cannot be attributed with certainty to the intact heptapeptide.
• No study of any SPO batch exists; the literature concerns material made by the research groups themselves.

Handling and storage

Selank 10MG is supplied as lyophilized powder in a sealed vial. Keep unopened vials frozen at −20 °C, dry and away from light, and avoid repeated freeze–thaw cycles. Reconstitution solvents such as bacteriostatic water are listed separately; concentrations and protocols are set by the researcher. Record the batch number from the vial label in your inventory and compare it with any report in the COA library.

References

1. Vyunova TV, Andreeva L, Shevchenko K et al. (2018). Peptide-based Anxiolytics: The Molecular Aspects of Heptapeptide Selank Biological Activity. Protein and peptide letters 25(10):914-923. doi:10.2174/0929866525666180925144642. PMID 30255741
2. Czabak-Garbacz R, Cygan B, Wolański L et al. (2006). Influence of long-term treatment with tuftsin analogue TP-7 on the anxiety-phobic states and body weight. Pharmacological reports : PR 58(4):562-7. PMID 16963804
3. Kozlovskaya MM, Kozlovskii II, Val'dman EA et al. (2003). Selank and short peptides of the tuftsin family in the regulation of adaptive behavior in stress. Neuroscience and behavioral physiology 33(9):853-60. doi:10.1023/a:1025988519919. PMID 14969422
4. Zozulya AA, Kost NV, Yu Sokolov O et al. (2001). The inhibitory effect of Selank on enkephalin-degrading enzymes as a possible mechanism of its anxiolytic activity. Bulletin of experimental biology and medicine 131(4):315-7. doi:10.1023/a:1017979514274. PMID 11550013
5. Sokolov OY, Meshavkin VK, Kost NV et al. (2002). Effects of Selank on behavioral reactions and activities of plasma enkephalin-degrading enzymes in mice with different phenotypes of emotional and stress reactions. Bulletin of experimental biology and medicine 133(2):133-5. doi:10.1023/a:1015582302311. PMID 12432865
6. Zolotarev IuA, Dadaian AK, Dolotov OV et al. (2006). [Evenly tritium-labeled peptides and their in vivo and in vitro biodegradation]. Bioorganicheskaia khimiia 32(2):183-91. PMID 16637290
7. Volkova A, Shadrina M, Kolomin T et al. (2016). Selank Administration Affects the Expression of Some Genes Involved in GABAergic Neurotransmission. Frontiers in pharmacology 7:31. doi:10.3389/fphar.2016.00031. PMID 26924987
8. Filatova E, Kasian A, Kolomin T et al. (2017). GABA, Selank, and Olanzapine Affect the Expression of Genes Involved in GABAergic Neurotransmission in IMR-32 Cells. Frontiers in pharmacology 8:89. doi:10.3389/fphar.2017.00089. PMID 28293190
9. 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 2017:5091027. doi:10.1155/2017/5091027. PMID 28280289
10. Kozlovskii II, Danchev ND (2003). The optimizing action of the synthetic peptide Selank on a conditioned active avoidance reflex in rats. Neuroscience and behavioral physiology 33(7):639-43. doi:10.1023/a:1024444321191. PMID 14552529
11. Kolik LG, Nadorova AV, Antipova TA et al. (2019). Selank, Peptide Analogue of Tuftsin, Protects Against Ethanol-Induced Memory Impairment by Regulating of BDNF Content in the Hippocampus and Prefrontal Cortex in Rats. Bulletin of experimental biology and medicine 167(5):641-644. doi:10.1007/s10517-019-04588-9. PMID 31625062
12. Konstantinopolsky MA, Chernyakova IV, Kolik LG (2022). Selank, a Peptide Analog of Tuftsin, Attenuates Aversive Signs of Morphine Withdrawal in Rats. Bulletin of experimental biology and medicine 173(6):730-733. doi:10.1007/s10517-022-05624-x. PMID 36322304
13. Kolomin T, Shadrina M, Andreeva L et al. (2011). Expression of inflammation-related genes in mouse spleen under tuftsin analog Selank. Regulatory peptides 170(1-3):18-23. doi:10.1016/j.regpep.2011.05.001. PMID 21609736
14. Kolomin T, Morozova M, Volkova A et al. (2014). The temporary dynamics of inflammation-related genes expression under tuftsin analog Selank action. Molecular immunology 58(1):50-5. doi:10.1016/j.molimm.2013.11.002. PMID 24291245
15. Ershov FI, Uchakin PN, Uchakina ON et al. (2009). [Antiviral activity of immunomodulator Selank in experimental influenza infection]. Voprosy virusologii 54(5):19-24. PMID 19882898
16. 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 108(4):38-48. PMID 18454096
17. Medvedev VE, Tereshchenko ON, Israelian AIu et al. (2014). [A comparison of the anxiolytic effect and tolerability of selank and phenazepam in the treatment of anxiety disorders]. Zhurnal nevrologii i psikhiatrii imeni S.S. Korsakova 114(7):17-22. PMID 25176261
18. 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 108(5):71-5. PMID 18577961
19. Doyno CR, White CM (2021). Sedative-Hypnotic Agents That Impact Gamma-Aminobutyric Acid Receptors: Focus on Flunitrazepam, Gamma-Hydroxybutyric Acid, Phenibut, and Selank. Journal of clinical pharmacology 61 Suppl 2:S114-S128. doi:10.1002/jcph.1922. PMID 34396551