Selank Peptide Spray

Selank Research & Scientific Overview

Jump to: Structure | Mechanism | Studies | Pharmacokinetics | Protocols | Limitations | Lead Researcher | References

Selank Molecular Structure & Chemical Properties {#structure}

Selank is a synthetic heptapeptide developed in the early 1990s at the Institute of Molecular Genetics of the Russian Academy of Sciences, designed as a metabolically stable analog of tuftsin – a naturally occurring immunomodulatory tetrapeptide (Thr-Lys-Pro-Arg) derived from the heavy chain of human immunoglobulin G. To address tuftsin’s rapid enzymatic degradation, researchers extended the original tetrapeptide sequence at the C-terminus with the tripeptide Pro-Gly-Pro, yielding the final heptapeptide structure Thr-Lys-Pro-Arg-Pro-Gly-Pro (TKPRPGP). This structural modification substantially improves metabolic stability while preserving and expanding the biological activity of the parent molecule. Selank has accumulated decades of preclinical and limited clinical research primarily from Russian institutions, with particular emphasis on its anxiolytic, nootropic, and immunomodulatory properties and on intranasal delivery as its preferred research administration route.

Chemical Structure

[IMAGE PLACEHOLDER] Insert 2D chemical structure image here Image URL: https://pubchem.ncbi.nlm.nih.gov/image/imgsrv.fcgi?cid=11765600&t=l Alt text: Selank molecular structure diagram showing heptapeptide backbone Source credit: PubChem Position: Center-aligned below heading

2D molecular structure (Source: PubChem)

Technical Specifications

Property

Value

CAS Number

129954-34-3

Molecular Formula

C33H57N11O9 (subscripted)

Molecular Weight

751.88 g/mol

Amino Acid Sequence

Thr-Lys-Pro-Arg-Pro-Gly-Pro (TKPRPGP)

Half-Life (Plasma)

~20-30 minutes (rat models)

Stability

Enhanced stability vs. tuftsin due to C-terminal Pro-Gly-Pro extension; hydrophilic character

Solubility

Water soluble; prepared as aqueous nasal solution in research protocols

Storage

Lyophilized: -20 degrees C or below; Reconstituted: 2-8 degrees C

Selank’s isoelectric point is approximately 11.5, indicating a basic character under neutral pH conditions. The peptide is structurally linear, lacking disulfide bonds or cyclic elements, and its sequence rich in polar amino acids – threonine, lysine, and arginine – accounts for its marked hydrophilicity and aqueous solubility.

Selank Mechanism of Action {#mechanism}

Selank exerts its neuropsychopharmacological effects through multiple intersecting pathways rather than a single defined receptor target. The most extensively studied mechanism involves allosteric modulation of the GABAergic system, though research has also documented effects on monoamine neurotransmitter metabolism, enkephalin degradation pathways, and neurotrophic factor expression – all of which may contribute synergistically to the behavioral effects observed in preclinical models.

Primary Cellular Pathways
GABAergic System Modulation – Anxiolytic Activity

Research has demonstrated that Selank influences the specific binding of GABA to GABA-A receptors, likely through allosteric modulation that alters the number of specific GABA binding sites without affecting receptor affinity[1]. Studies in rat frontal cortex found that intranasal administration (300 mcg/kg) produced significant changes in the mRNA expression of 45 genes involved in GABAergic neurotransmission within one hour of administration[2]. Key effects documented in rodent models include:

Altered expression of major GABA-A receptor subunit genes, including GABRB3, GABRE, and GABRQ
Regulation of ion channels involved in GABA transport
Modulation of dopamine receptor subtypes (DRD3, DRD5) and serotonin receptor genes simultaneously
Changes in HCRT (hypocretin/orexin) gene expression, which may explain the absence of sedative effects observed with classical benzodiazepines
Enkephalin Degradation Inhibition

Selank, along with the closely related peptide Semax, has been found to inhibit aminopeptidase N (APN) and dipeptidyl peptidase IV (DPP-IV), enzymes responsible for the degradation of enkephalins and other endogenous regulatory peptides[3]. By attenuating enkephalin catabolism, Selank effectively prolongs the biological activity of endogenous opioid peptides:

Increased leu-enkephalin half-life in blood plasma observed in clinical study participants
Enkephalin-related effects on anxiety appear independent of direct opioid receptor activation
Studies in morphine-dependent rats showed Selank (0.3 mg/kg intraperitoneally) reduced withdrawal syndrome severity by approximately 40%, with effects partially blocked by naloxone[4]
BDNF Upregulation – Neurotrophic Support

Intranasal administration of Selank has been shown to regulate brain-derived neurotrophic factor (BDNF) expression in rat hippocampus in vivo[5]. Biodistribution studies using radiolabeled peptide confirmed brain penetration following intranasal delivery. Key findings include:

Doses of 250 and 500 mcg/kg increased BDNF mRNA levels at 3 hours post-administration
BDNF protein levels were elevated at 24 hours post-administration at both doses tested
BDNF upregulation in the hippocampus is specifically associated with local synthesis, not axonal transport from remote brain regions
Cognitive-protective effects against ethanol-induced memory impairment correlated with BDNF modulation in hippocampus and prefrontal cortex
Monoamine Neurotransmitter Modulation

Research in BALB/c and C57BL/6 mice documented that Selank (300 mcg/kg) produced strain-dependent changes in the brain content of noradrenaline, dopamine, serotonin, and their major metabolites across hippocampus, hypothalamus, and frontal cortex[6]. Notable observations include:

Induced serotonin metabolism changes within 30 minutes of administration
Selank elevated serotonin metabolism even in rats pre-treated with a serotonin synthesis inhibitor (p-chlorophenylalanine) – an effect not produced by tuftsin alone
Dopamine metabolite changes (3,4-dihydroxyphenylacetic and homovanillic acids) observed in hippocampus and frontal cortex
Immunomodulatory Activity

As a structural tuftsin analog, Selank retains meaningful immunomodulatory properties. Studies in patients with anxiety-asthenic disorders found that Selank modulated IL-6 expression, suppressing levels in subjects with depression while leaving healthy controls unaffected[7]. Research has also documented effects on T-helper cell cytokine balance and on the expression of inflammation-related genes in mouse spleen.

[CALLOUT BOX – Highlighted] Key Mechanistic Insight: Selank’s multi-target profile – encompassing GABAergic allosteric modulation, enkephalin system engagement, BDNF upregulation, and monoamine regulation – distinguishes it mechanistically from classical benzodiazepines. However, no single primary receptor or binding site has been definitively identified, which remains a significant gap in the current literature. [END CALLOUT BOX]

Selank Research Applications & Key Findings {#studies}
Anxiety and Stress Research
Generalized Anxiety Disorder Models

The most extensively studied application of Selank is its anxiolytic activity across multiple preclinical models and in a limited number of clinical investigations conducted in Russia. In the elevated plus maze and open field behavioral tests in rats, intranasal Selank (300 mcg/kg) consistently reduced anxiety-like behaviors, with effects considered comparable to those of classical benzodiazepine drugs[8].

A clinical study examined 62 patients with generalized anxiety disorder (GAD) and neurasthenia, comparing Selank (30 patients) to the benzodiazepine medazepam (32 patients)[9]. Key findings included:

Comparable anxiolytic efficacy between Selank and medazepam on standard psychometric scales (Hamilton, Zung, CGI)
Selank additionally demonstrated antiasthenic and psychostimulant properties not observed with medazepam
Selank subjects showed improved leu-enkephalin half-life, correlating with reduced anxiety severity
Absence of amnesia, withdrawal syndrome, and dependence – side effects commonly associated with benzodiazepines

A separate rodent study found that combined administration of Selank and diazepam under unpredictable chronic mild stress conditions amplified anxiolytic outcomes beyond either compound administered alone, suggesting potential additive effects on GABA-A receptors[10].

Cognitive Research
Memory and Learning Models

Research in rodent models has examined Selank’s effects on cognitive processes. In aged rats (9 months), Selank (0.3 mg/kg per day for 7 days intraperitoneally) produced cognitive-stimulating effects in the object recognition test and prevented the formation of ethanol-induced memory and attention disturbances during alcohol withdrawal[5]. Specific findings included:

Prevented ethanol-induced increases in hippocampal and frontal cortex BDNF associated with alcohol withdrawal
Restored cognitive parameters in older rats not previously exposed to ethanol
Improved avoidance conditioning in rodent active avoidance tests
Neurological Research
Parkinson’s Disease Models

Research examining Selank in rodent models of parkinsonism induced by 6-hydroxydopamine (6-OHDA), a neurotoxin targeting catecholaminergic systems, found that Selank administration restored certain cognitive and behavioral processes disrupted by dopaminergic damage[11]. This research remains preliminary and mechanistically poorly characterized.

Opiate Withdrawal Models

Studies in morphine-dependent rats demonstrated that intraperitoneal Selank (0.3 mg/kg) reduced the total index of naloxone-precipitated morphine withdrawal syndrome by approximately 40%, attenuating convulsive reactions, ptosis, and posture disorders, while increasing tactile sensitivity thresholds[4]. By comparison, diazepam (2 mg/kg) reduced the withdrawal index by approximately 49%, indicating Selank showed somewhat lower but still notable activity in this model.

Immunomodulation Research
Cytokine and Antiviral Studies

Research into Selank’s immunomodulatory properties has documented modulation of IL-6 expression in anxiety-asthenic disorder patients and effects on T-helper cell cytokine balance[7]. Additional studies have examined inflammation-related gene expression dynamics in mouse spleen following single and repeated Selank administration, finding temporal changes in C3, Casp1, Il2rg, and Xcr1 genes[12]. Separate preclinical research identified antiviral activity against influenza A (H3N2), herpes simplex virus (HSV-1 and HSV-2), and cytomegalovirus (CMV) in animal and cell-based models[13].

[CALLOUT BOX – Highlighted] Critical Research Limitation: The majority of Selank clinical research has been conducted exclusively at Russian institutions, with studies largely published in Russian-language journals and only the abstracts indexed in international databases. Independent international replication of these findings is very limited. All clinical findings should be interpreted with caution given these constraints. [END CALLOUT BOX]

Selank Pharmacokinetics & Metabolism {#pharmacokinetics}
Absorption & Distribution via Intranasal Route

Intranasal administration has been established in published research as the preferred delivery route for Selank, valued specifically because it enables direct nose-to-brain transport via olfactory and trigeminal nerve pathways[14]. Studies using radiolabeled Selank confirmed brain penetration following intranasal delivery, with peptide detected in multiple brain regions including cortex, hippocampus, and hypothalamus. Key absorption characteristics documented in rat models include:

Rapid systemic absorption with peak plasma concentrations occurring within 15-30 minutes following intraperitoneal administration
Nose-to-brain direct transport observed for intranasal route, bypassing systemic circulation
Research comparing intranasal vs. intraperitoneal routes in BALB/c and C57BL/6 mice found route-dependent differences in behavioral outcomes, consistent with distinct pharmacokinetic profiles[15]
Oral bioavailability is not established for Selank given its peptide nature
Metabolism & Elimination

Biodegradation studies using evenly tritium-labeled Selank identified the major metabolic products in blood plasma as the pentapeptide TKPRP, the tripeptide TKP, and the dipeptides RP and GP[14]. Key pharmacokinetic parameters observed in animal models include:

Plasma half-life approximately 20-30 minutes in rat models
Rapid hepatic metabolism through aminopeptidase activity
Complete clearance from circulation within approximately 10 minutes using sensitive detection methods in some studies
Pharmacodynamic effects persist considerably longer than the plasma half-life would predict, suggesting either active metabolite contributions or persistent receptor-mediated signaling

The dipeptide GP and tripeptide PGP, products of Selank biodegradation, are themselves reported to have independent biological activity, potentially contributing to the overall pharmacodynamic profile after parent peptide clearance.

Excretion Pathways

Excretion data for Selank remains incompletely characterized in published literature:

Likely renal elimination of peptide degradation fragments based on metabolic pathway analysis
No documented bioaccumulation in chronic dosing studies (animal models)
Excretion kinetics for the parent peptide and active metabolites require further investigation
Selank Research Protocols & Administration {#protocols}
Dosing in Published Research

Published preclinical and clinical research has employed a range of Selank doses depending on species, administration route, and research model:

Rat intranasal studies: 300 mcg/kg is the most commonly cited anxiolytic dose in preclinical literature
Rat intraperitoneal studies: 250-500 mcg/kg range for neurotrophic and cognitive studies; 0.3 mg/kg for opiate withdrawal models
Mouse studies: 250-300 mcg/kg typical range; dose response examined from 0.01 to 0.3 mg/kg depending on model
Clinical studies (Russia): Approximately 250 mcg to 3 mg daily ranges reported in Russian clinical protocols

Important: These are experimental doses used in animal studies and cannot be extrapolated to other species due to significant differences in metabolism, pharmacokinetics, receptor expression, nose-to-brain transport efficiency, and peptide degradation rates. Species-specific factors profoundly influence both efficacy and safety profiles.

Administration Routes in Research

Multiple delivery methods have been studied, with intranasal being the most extensively documented:

Intranasal administration – Clinically preferred research route; enables direct nose-to-brain transport; used in the majority of preclinical and clinical Selank studies
Intraperitoneal injection – Common in rodent behavioral pharmacology studies; reliable systemic delivery
Subcutaneous injection – Used in systemic delivery studies; documented in some Russian clinical protocols
Intravenous injection – Used primarily for pharmacokinetic characterization and biodegradation studies
Common Model Organisms

Selank has been studied across multiple species and cell systems:

Rats (Wistar, Sprague-Dawley outbred) – Primary research model; used in anxiety, cognitive, opioid withdrawal, and BDNF studies
Mice (BALB/c, C57BL/6) – Used for strain-dependent behavioral comparisons; genetic susceptibility research
Non-human primates (rhesus monkeys) – Limited studies examining neurosis models and behavioral restoration
Human subjects (clinical) – Limited clinical studies with GAD and neurasthenia patients conducted at Russian institutions
Cell culture – IMR-32 neuroblastoma cells; rat frontal cortex tissue; spleen cells for immunomodulatory studies
Research Limitations & Regulatory Status {#limitations}
Critical Gaps in Current Evidence

Despite decades of preclinical investigation and limited clinical research, Selank faces significant translational barriers that constrain interpretation of the available evidence base.

Geographic and Publication Bias

The most consequential limitation in Selank research is structural rather than purely scientific:

Overwhelming majority of studies conducted exclusively at Russian and Ukrainian institutions
Most clinical data published in Russian-language journals, with only abstracts accessible through international databases like PubMed
No independent international replication of clinical findings has been published in peer-reviewed Western literature
Clinical study methodologies are difficult to fully assess given limited access to complete publications
Mechanistic Understanding Gaps

Fundamental aspects of Selank’s mechanism remain unresolved:

No single primary receptor or binding target has been definitively identified
Whether anxiolytic effects are primarily driven by GABAergic modulation, enkephalin pathway effects, monoamine changes, or BDNF upregulation – or some combination – remains debated
Active metabolite contributions (RP, GP, PGP fragments) to total biological activity are not fully characterized
Tissue-specific receptor interactions require further clarification across brain regions
Long-Term Safety Considerations

Critical safety questions remain inadequately addressed:

Chronic use effects beyond short-term protocols unstudied even in animal models
Immunogenicity risk cannot be excluded given the peptide’s partial homology to immunoglobulin fragments
Interaction potential with psychiatric medications, including benzodiazepines, is only partially characterized
Reproductive and developmental toxicity has not been systematically investigated
Cancer cell interaction and tumor progression effects are unstudied
Regulatory & Competitive Sport Status
FDA Position

Selank has not received FDA approval for any indication in the United States:

Classified as an unapproved drug substance under FDA jurisdiction
Not recognized as GRAS (Generally Recognized as Safe)
Not approved for human use, medical compounding, or veterinary applications in the US
Approved in Russia (2009) for generalized anxiety disorder; available by prescription through Russian and Ukrainian pharmacies – this approval does not extend to other jurisdictions
WADA Status

Selank does not appear on the World Anti-Doping Agency’s current prohibited list as a specifically named substance; however:

It may fall under broader categories of peptide hormones and regulatory peptides subject to WADA scrutiny
Researchers and affiliated athletes should consult current WADA documentation before including Selank in protocols involving competitive athletes
Status may change as detection methods and prohibited substance lists evolve

Research Classification: Selank is available only for laboratory research use outside Russia and Ukraine. It is not intended for human consumption, medical use, or veterinary applications in jurisdictions where it lacks regulatory approval. All research must be conducted under appropriate ethical oversight and institutional review board approval where applicable.

Lead Researcher Spotlight {#lead-researcher}
Nikolai F. Myasoedov, PhD

Department of Chemistry of Physiologically Active Compounds Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russia

Nikolai F. Myasoedov has been among the principal investigators driving Selank research since the peptide’s development in the early 1990s at the Institute of Molecular Genetics of the Russian Academy of Sciences, co-designing the structural modifications to tuftsin that produced the final heptapeptide. His laboratory has contributed to the synthesis and characterization of Selank, as well as to mechanistic investigations spanning GABAergic modulation, enkephalin degradation, BDNF regulation, and immunomodulatory pathways. His work has established Selank as one of the most extensively studied neuropeptide anxiolytics in the Russian pharmacological literature.

Dr. Myasoedov’s key research focus areas include:

Synthesis and structural optimization of regulatory neuropeptides including Selank and the related peptide Semax
Molecular mechanisms of short regulatory peptide action in the central nervous system
Enkephalin degradation pathways and enzyme inhibition by peptide analogs
Gene expression profiling in hippocampus and spleen following neuropeptide administration
Clinical investigations of Selank in anxiety-spectrum disorders conducted at Russian institutions

Disclaimer: This spotlight is provided for educational purposes to acknowledge scientific contributions to Selank research. Cenexa Labs has no affiliation with Dr. Myasoedov or the Institute of Molecular Genetics of the Russian Academy of Sciences, and this information does not constitute an endorsement of any products or services.

References {#references}
V’yunova, T.V., Andreeva, L.A., Shevchenko, K.V., Shevchenko, V.P., & Myasoedov, N.F. (2014). Peptide regulation of specific ligand-receptor interactions of GABA with the plasma membranes of nerve cells. Neurochemical Journal, 8, 259-264. PubMed

Volkova, A., Shadrina, M., Kolomin, T., Andreeva, L., Limborska, S., Myasoedov, N., & Slominsky, P. (2016). Selank administration affects the expression of some genes involved in GABAergic neurotransmission. Frontiers in Pharmacology, 7, 31. PubMed

Kost, N.V., Sokolov, O., Gabaeva, M.V., Grivennikov, I.A., Andreeva, L.A., Myasoedov, N.F., & Zozulia, A.A. (2001). Semax and selank inhibit the enkephalin-degrading enzymes from human serum. Bioorganicheskaya Khimiya, 27(3), 180-183. PubMed

Koroleva, S.V., Danchev, N.D., & Myasoedov, N.F. (2012). Activity of a peptide tuftsin analogue Selank in the naloxone-precipitated morphine withdrawal model. Eksperimental’naya i Klinicheskaya Farmakologiya, 75(5), 7-10. PubMed

Inozemtseva, L.S., Karpenko, E.A., Dolotov, O.V., Levitskaya, N.G., Kamensky, A.A., Andreeva, L.A., & Grivennikov, I.A. (2008). Intranasal administration of the peptide Selank regulates BDNF expression in the rat hippocampus in vivo. Doklady Biological Sciences, 421, 241-243. PubMed

Narkevich, V.B., Kudrin, V.S., Klodt, P.M., Pokrovskii, A.A., Kozlovskaya, M.M., Maiskii, A.I., & Raevskii, K.S. (2008). Effects of heptapeptide selank on the content of monoamines and their metabolites in the brain of BALB/C and C57Bl/6 mice: a comparative study. Eksperimental’naya i Klinicheskaya Farmakologiya, 71(5), 8-12. PubMed

Uchakina, O.N., Uchakin, P.N., Miasoedov, N.F., Andreeva, L.A., Scherbenko, V.E., Mezentseva, M.V., & Zozulia, A.A. (2008). Immunomodulatory effects of selank in patients with anxiety-asthenic disorders. Zhurnal Nevrologii i Psikhiatrii Imeni S.S. Korsakova, 108(5), 71-75. PubMed

Kozlovskaya, M.M., Kozlovskii, I.I., Val’dman, E.A., & Seredenin, S.B. (2003). Selank and short peptides of the tuftsin family in the regulation of adaptive behavior in stress. Neuroscience and Behavioral Physiology, 33(8), 853-860. PubMed

Zozulia, A.A., Neznamov, G.G., Siuniakov, T.S., Kost, N.V., Gabaeva, M.V., Sokolov, O.I., Serebriakova, E.V., Siranchieva, O.A., Andriushenko, A.V., Telesheva, E.S., Siuniakov, S.A., Smulevich, A.B., Miasoedov, N.F., & Seredenin, S.B. (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. PubMed

Kasian, A., Kolomin, T., Andreeva, L., Bondarenko, E., Limborska, S., Myasoedov, N., & Slominsky, P. (2017). Peptide Selank enhances the effect of diazepam in reducing anxiety in unpredictable chronic mild stress conditions in rats. Behavioural Neurology, 2017, 5091027. PubMed

Slominsky, P.A., Shadrina, M.I., Kolomin, T.A., et al. (2017). Peptides Semax and Selank affect the behavior of rats with 6-OHDA induced PD-like parkinsonism. Doklady Biological Sciences, 474(1), 106-109. PubMed

Kolomin, T., Morozova, M., Volkova, A., Shadrina, M., Andreeva, L., Slominsky, P., & Myasoedov, N. (2014). The temporary dynamics of inflammation-related genes expression under tuftsin analog Selank action. Molecular Immunology, 58(1), 50-55. PubMed

Ershov, F.I., Uchakin, P.N., Uchakina, O.N., Mezentseva, M.V., Alekseeva, L.A., & Miasoedov, N.F. (2009). Antiviral activity of immunomodulator Selank in experimental influenza infection. Voprosy Virusologii, 54(5), 19-24. PubMed

Zolotarev, Y.A., Dadayan, A.K., Dolotov, O.V., Kozik, V.S., Kost, N.V., Sokolov, O.Y., & Myasoedov, N.F. (2006). Evenly tritium labeled peptides in study of peptide in vivo and in vitro biodegradation. Russian Journal of Bioorganic Chemistry, 32(2), 166-173. PubMed

Vasil’eva, E.V., Kondrakhin, E.A., Salimov, R.M., & Kovalev, G.I. (2008). Comparison of pharmacological effects of heptapeptide Selank after intranasal and intraperitoneal administration to BALB/c and C57BL/6 mice. Eksperimental’naya i Klinicheskaya Farmakologiya, 71(5), 13-16. PubMed

Filatova, E., Kasian, A., Kolomin, T., Rybalkina, E., Alieva, A., Andreeva, L., Limborska, S., Myasoedov, N., Pavlova, G., Slominsky, P., & Shadrina, M. (2017). GABA, Selank, and olanzapine affect the expression of genes involved in GABAergic neurotransmission in IMR-32 cells. Frontiers in Pharmacology, 8, 89. PubMed

All references open in new window. These citations are provided for educational and research purposes only. This information is not intended to diagnose, treat, cure, or prevent any disease. Selank is intended for laboratory research use only.