Selank is a synthetic heptapeptide developed at the Institute of Molecular Genetics of the Russian Academy of Sciences and the V.V. Zakusov Research Institute of Pharmacology. Derived from the endogenous immunomodulatory tetrapeptide tuftsin, Selank was engineered to retain tuftsin’s biological activity while gaining substantially improved metabolic stability. Over several decades of preclinical investigation and limited clinical research, Selank has accumulated a body of literature spanning anxiolytic pharmacology, cognitive enhancement, BDNF modulation, and immune regulation. This article summarizes that research literature for educational purposes. All content is for informational and research use only.
Molecular Profile
Selank’s sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro (TKPRPGP), comprising the tuftsin core sequence (TKPR) extended at the C-terminus with a Pro-Gly-Pro tripeptide. This C-terminal extension was specifically designed to reduce rapid enzymatic degradation, increasing the peptide’s half-life relative to native tuftsin while preserving its core biological activity.
Tuftsin itself is a tetrapeptide fragment cleaved from the Fc region of immunoglobulin G heavy chains. It functions as an endogenous immunostimulatory signal, activating phagocytic cells and modulating innate immune responses. Selank retains this immunomodulatory profile while demonstrating additional central nervous system effects that tuftsin itself does not robustly exhibit — likely owing to its enhanced blood-brain barrier penetration and CNS bioavailability following intranasal or systemic administration.
Key Parameters: – Molecular formula: C₃₃H₅₇N₁₁O₉ – Molecular weight: ~751.87 Da – Route in research: typically intranasal or intraperitoneal in preclinical models – CAS Number: 129954-34-3
Tuftsin Origins and Pharmacological Design
The decision to scaffold Selank on tuftsin was deliberate. Tuftsin had been well-characterized as an endogenous regulator bridging immune and neuroendocrine systems, with receptors identified in both peripheral immune cells and specific brain regions. Early anxiety research suggested that tuftsin-like structures might engage the enkephalin system and GABAergic circuits.
Research from 1998 confirmed the anxiolytic activity of a tuftsin analog in inbred mice with different emotional stress phenotypes, demonstrating behavioral effects analogous to classical anxiolytics but through distinct mechanisms (PMID: 9583175). Selank built on this foundation by offering improved stability and a more complete CNS pharmacological profile, ultimately entering clinical investigation in Russia for generalized anxiety disorder (GAD) and neurasthenia.
Anxiolytic Research: GABAergic and Enkephalinergic Mechanisms
Selank’s anxiolytic effects in preclinical models are well-documented and appear to involve at least two distinct mechanistic pathways. First, Selank has been shown to modulate GABAergic neurotransmission. A key study by Volkova and colleagues demonstrated that Selank administration affects the expression of genes involved in GABAergic neurotransmission — including GABA-A receptor subunit genes — in a manner consistent with anxiolytic drug action (PMC: 4757669).
Second, Selank interacts with the enkephalin system. Clinical-level research by Uchakina et al. compared Selank against the benzodiazepine medazepam in 62 patients with GAD and neurasthenia. Results showed that Selank produced comparable anxiolytic effects on Hamilton and Zung psychometric scales while demonstrating activity on blood enkephalin measurements, suggesting a role for endogenous opioid peptides in its mechanism of action (PMID: 18454096). Importantly, enkephalin-mediated anxiolysis does not carry the typical dependence, sedation, or cognitive-impairment profile associated with benzodiazepines.
BDNF Modulation Research
Among Selank’s most studied mechanisms is its influence on brain-derived neurotrophic factor (BDNF) — the primary neurotrophin governing neuronal survival, synaptic plasticity, long-term potentiation, and mood regulation. Two lines of research are particularly significant here.
In 2008, Inozemtseva and colleagues demonstrated that intranasal administration of Selank regulates BDNF expression in the rat hippocampus in vivo (PMID: 18841804). This finding was significant because it established a direct link between the peptide’s administration route (intranasal, clinically relevant) and BDNF upregulation in a brain region central to memory formation and anxiety regulation.
A 2019 study by Chubarev et al. extended this finding to a model of alcohol-induced neurodegeneration, showing that Selank protected against ethanol-induced memory impairment by regulating BDNF content in both the hippocampus and prefrontal cortex of rats (PMID: 31625062). Selank-treated animals showed prevention of ethanol-induced BDNF dysregulation and performed significantly better in object recognition memory tasks.
These results position BDNF modulation as a core component of Selank’s nootropic and neuroprotective activity, potentially explaining both its anxiolytic effects (reduced hippocampal BDNF is associated with anxiety and depression phenotypes) and its cognitive-enhancing properties.
Cognitive Enhancement Research
Beyond anxiety, Selank has been investigated for its effects on learning, memory, and attention. Preclinical comparisons of intranasal versus intraperitoneal administration in BALB/c and C57BL/6 mice demonstrated that both routes produced anxiolytic and cognitive-enhancing effects in elevated-plus-maze and other behavioral paradigms, with route-dependent differences in potency and kinetics (PMID: 29787664).
The cognitive effects of Selank appear to operate through multiple pathways: BDNF upregulation (supporting synaptic long-term potentiation), enkephalin modulation (which affects memory consolidation and retrieval), and potential serotonergic system interactions. The peptide’s profile in cognitive research has been described as “nootropic” — improving learning and memory without the stimulant effects or dependence liabilities of classical psychostimulant compounds.
Immune Modulation Research
Selank’s origins as a tuftsin analog ensure that immune modulation remains a central aspect of its biological research profile. Tuftsin is known to stimulate phagocytosis, enhance NK cell activity, and modulate cytokine production. Selank retains and extends these properties.
Research has shown that Selank modulates the expression of interleukin-6 (IL-6) and influences the balance of T-helper cell cytokines. This bidirectional immune modulation — neither simple stimulation nor suppression — may be relevant to research on stress-induced immune dysregulation, as chronic stress typically shifts cytokine profiles in ways that exacerbate both psychological and somatic symptoms. Selank’s simultaneous action on CNS anxiety pathways and peripheral immune regulation makes it an interesting tool for studying the neuro-immune interface.
Compound Information
- Chemical Name: Selank (L-threonyl-L-lysyl-L-prolyl-L-arginyl-L-prolylglycyl-L-proline)
- Sequence: TKPRPGP
- Molecular Weight: ~751.87 Da
- Classification: Synthetic anxiolytic neuropeptide; tuftsin analog
- CAS Number: 129954-34-3
- Research Storage: Lyophilized powder; store at −20°C; reconstitute in sterile saline or bacteriostatic water for research applications
References
- Uchakina ON, Uchakin PN, Miasoedov NF, 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):38-42. PMID:18454096
- Inozemtseva LS, Karpenko EA, Dolotov OV, et al. Intranasal administration of the peptide Selank regulates BDNF expression in the rat hippocampus in vivo. Dokl Biol Sci. 2008;421:241-243. PMID:18841804
- Chubarev VN, Tarasov VV, Lozovoy MA, 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. Curr Pharm Des. 2019;25(33):3569-3574. PMID:31625062
- Babichev VN, Shishkina IV, Ignatov SA, 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. 1997;47(5):1022-1030. PMID:9583175
- Norkina LN, Karpenko EA, Dolotov OV, et al. Comparison of pharmacological effects of heptapeptide Selank after intranasal and intraperitoneal administration to BALB/c and C57BL/6 mice. Exp Biol Med (Maywood). 2018;(5):78-83. PMID:29787664
- 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. PMID:26924987
Research Use Disclaimer: Selank is sold by Rejuven8 Peptides strictly for in vitro and preclinical research use only. It is not intended for human consumption, veterinary use, or any therapeutic application. This content is educational and does not constitute medical advice. Always comply with applicable laws and institutional guidelines governing peptide research.
All products are sold for research purposes only. Not for human consumption. These statements have not been evaluated by the FDA. This content is for informational and educational purposes only and does not constitute medical advice.
