Selank — Research Overview
Chemical Name: Thr-Lys-Pro-Arg-Pro-Gly-Pro (threonine-lysine-proline-arginine-proline-glycine-proline) Abbreviation/Code: Selank (also designated TP-7 in some research literature) Sequence: TKPRPGP (single-letter amino acid code) Structure: Synthetic heptapeptide (7 amino acids) — a metabolically stabilized analog of the endogenous immunomodulatory tetrapeptide tuftsin (Thr-Lys-Pro-Arg) Parent Compound: Tuftsin — a naturally occurring tetrapeptide fragment of the heavy chain of human immunoglobulin G (IgG). Tuftsin is released from IgG by splenic and peripheral enzymes and functions as an endogenous immunostimulatory signal activating phagocytic cells including neutrophils, monocytes, and macrophages. Tuftsin was first described by Najjar and colleagues in the 1970s. Structural Modification from Tuftsin: The Pro-Gly-Pro tripeptide was added to the C-terminus of tuftsin’s Thr-Lys-Pro-Arg tetrapeptide sequence to improve metabolic stability. This C-terminal extension substantially prolongs the peptide’s half-life relative to the rapidly degraded tuftsin, enabling sustained neuropsychotropic activity without continuous infusion. The resulting heptapeptide retains tuftsin’s immunomodulatory activity while additionally expressing pronounced anxiolytic, nootropic, and monoaminergic effects. Development: Institute of Molecular Genetics, Russian Academy of Sciences, in collaboration with the V.V. Zakusov Research Institute of Pharmacology, Russian Academy of Medical Sciences. Developed under the direction of Nikolai Myasoedov’s laboratory. Russian Regulatory Status: Registered in the Russian Federation as a pharmaceutical drug for generalized anxiety disorder and neurasthenic conditions. Formulated as a 0.15% intranasal spray. One of a small number of peptide compounds anywhere in the world to have received national regulatory approval as an anxiolytic agent. FDA/EMA Status: Not approved by FDA or EMA for any indication. No ClinicalTrials.gov-registered Western Phase 1-3 development program as of this research compilation. Classified as a research compound in most Western jurisdictions. WADA Status: Not specifically listed on the WADA prohibited list as of current compilation. Category: Synthetic tuftsin analog / peptide anxiolytic / nootropic neuropeptide / GABA system modulator / enkephalinase inhibitor / BDNF upregulator / immunomodulatory research peptide
Research Use Only — Disclaimer
The scientific literature on this page is provided strictly for educational and informational purposes. All Rogue Compounds products are intended for in-vitro laboratory research use only and are not approved by the FDA for human or animal consumption. The studies referenced below are independent third-party peer-reviewed publications. Rogue Compounds makes no claims that any product diagnoses, treats, cures, or prevents any disease or condition. Researchers are responsible for compliance with all applicable local, state, and federal regulations.
What Is Selank?
Selank is a synthetic heptapeptide developed at the Institute of Molecular Genetics of the Russian Academy of Sciences as a metabolically stabilized analog of tuftsin — an endogenous tetrapeptide released from immunoglobulin G that regulates innate immune function. Its development began as an immunology project: the Myasoedov laboratory sought to improve tuftsin’s rapid in vivo degradation by adding three amino acids (Pro-Gly-Pro) to its C-terminus. The resulting heptapeptide proved markedly more stable than tuftsin while retaining immunomodulatory activity. What was not anticipated was the emergence of pronounced neuropsychotropic properties — anxiolytic, nootropic, and monoamine-modulating effects — that positioned Selank as one of the most pharmacologically multifaceted peptides in this catalog.
Selank’s distinctive research profile combines at least five distinct mechanistic contributions: GABAergic anxiolytic activity comparable to benzodiazepines without their adverse effects; enkephalinase inhibition that amplifies endogenous opioid signaling without receptor agonism; brain-derived neurotrophic factor (BDNF) upregulation in the hippocampus; monoamine (serotonin, dopamine, noradrenaline) system modulation; and immunomodulatory activity through its tuftsin ancestry. The convergence of these pathways in a single 7-amino-acid peptide constitutes a pharmacological profile that distinguishes Selank from all approved anxiolytic drug classes and from most research peptides.
Selank’s regulatory journey adds important clinical context: it is registered in Russia as a prescription intranasal spray (0.15% solution) for generalized anxiety disorder and neurasthenic conditions — one of only a handful of peptide compounds globally to achieve national regulatory approval as an anxiolytic agent. This regulatory approval, while outside the FDA/EMA framework, is backed by a body of published Russian clinical research including active comparator trials against benzodiazepines assessed with validated psychiatric rating scales. Understanding this research context — its strengths, limitations, and translational status relative to Western regulatory standards — is essential for accurate evaluation of Selank’s evidence base.
Tuftsin — The Endogenous Foundation
Tuftsin (Thr-Lys-Pro-Arg) is a naturally occurring peptide fragment of the IgG heavy chain Fc region that is released by two enzymes: a specific enzyme present in the spleen that cleaves tuftsin from a larger carrier segment, and a membrane-bound enzyme on leukocytes that completes the processing. Tuftsin was named after Tufts University, where it was first characterized by Vance Najjar and colleagues.
The endogenous functions of tuftsin include activation of phagocytic cells — primarily neutrophils, monocytes, and macrophages — promoting their phagocytic capacity, chemotaxis, and tumoricidal activity. Tuftsin has been studied as an immune enhancer in animal models of infection and tumor challenge. The peptide also has demonstrated central nervous system effects in animal studies, modulating behavior and biogenic amine levels, suggesting that its immunomodulatory and neuromodulatory roles are not entirely separable.
Selank carries forward all of tuftsin’s immunomodulatory activity while substantially extending its duration of action and adding the anxiolytic and nootropic dimensions that emerged from the C-terminal stabilization modification.
Mechanism of Action — Five Convergent Pathways
GABAergic modulation — the anxiolytic mechanism: Clinical studies have established Selank’s anxiolytic efficacy as comparable to low-dose benzodiazepines on validated psychiatric rating scales. The mechanistic basis for this anxiolytic activity involves the GABAergic neurotransmitter system — specifically, evidence of effects on GABAA receptor function and modulation of gene expression in the GABAergic system. Selank has been shown to increase GABAA receptor density in hippocampal neurons, enhancing the inhibitory effects of GABA in this critical structure involved in anxiety and emotional regulation. Gene expression studies showed that Selank administration affected mRNA levels of genes encoding GABA receptor subunits, transporters, and related proteins — though the precise gene expression changes vary between studies, and some studies found no changes in GABAergic gene expression, indicating that the mechanistic link to GABAergic function requires further characterization.
Critically, Selank’s GABA-related anxiolytic effect is not accompanied by the adverse effects characterizing benzodiazepine GABAergic modulation: no sedation, no amnesia, no tolerance development, no physical dependence, no withdrawal syndrome. This dissociation — anxiolytic efficacy without benzodiazepine-type adverse effects — is the central pharmacological claim that distinguishes Selank from the dominant anxiolytic drug class and that has driven its clinical development.
Enkephalinase inhibition — endogenous opioid preservation: Selank is a potent inhibitor of enzymes that degrade endogenous enkephalins (methionine-enkephalin and leucine-enkephalin) in blood serum. Enkephalins are endogenous opioid pentapeptides that act at delta opioid receptors to produce anxiolytic and mood-regulating effects in the CNS. By inhibiting their degradation, Selank extends the duration of enkephalin signaling — pharmacologically amplifying the endogenous opioid system without directly activating opioid receptors. This mechanism preserves the favorable delta-opioid anxiolytic signal without the respiratory depression, addiction potential, or tolerance associated with exogenous opioid receptor agonism.
The clinical relevance of this mechanism was directly demonstrated: patients with generalized anxiety disorder were found to have significantly reduced tau(1/2) leu-enkephalin levels (shorter enkephalin half-life, indicating increased degradation) compared to healthy controls, with this reduction correlating with disease duration and severity. Selank treatment in these patients increased tau(1/2) leu-enkephalin — normalizing enkephalin half-life and correlating with clinical improvement in anxiety symptoms.
BDNF upregulation in the hippocampus: Intranasal Selank administration in rats rapidly elevated brain-derived neurotrophic factor (BDNF) expression in the hippocampus. BDNF is a neurotrophic factor essential for neuronal survival, synaptic plasticity, and the process of neurogenesis in the adult hippocampus. Reduced hippocampal BDNF is consistently observed in depression and anxiety disorder animal models, while BDNF restoration is associated with antidepressant and anxiolytic effects. Selank’s hippocampal BDNF upregulation — occurring rapidly following intranasal administration — provides a neuroplasticity mechanism through which anxiolytic effects may be sustained and potentially persist after cessation of treatment. The 2019 study demonstrating Selank’s protective effect on ethanol-induced BDNF dysregulation in the hippocampus and prefrontal cortex further documented the BDNF connection, showing that Selank normalized (not merely elevated) ethanol-disrupted BDNF levels — a regulatory rather than simply stimulatory effect.
Monoamine neurotransmitter system modulation: Selank influences the metabolism and concentration of serotonin, dopamine, and noradrenaline in multiple brain regions including the hypothalamus, striatum, and cortex. Serotonin metabolism is particularly affected — Selank has been shown to induce metabolism of serotonin and influence serotonergic neurotransmission, providing a mechanism for its reported antidepressant-like and mood-stabilizing effects distinct from its GABAergic anxiolytic activity. Dopamine and noradrenaline modulation contributes to the antiasthenic and psychostimulant effects documented in clinical studies — the ability to reduce fatigue and enhance mental energy, which differentiates Selank from classic sedating anxiolytics. The psychostimulant-like dimension is a significant clinical distinction: benzodiazepines impair cognitive function and reduce alertness, while Selank appears to improve both cognitive performance and mood simultaneously with anxiety reduction.
Immunomodulatory activity — the tuftsin inheritance: As a tuftsin structural analog, Selank modulates the immune system in addition to its CNS effects. In clinical studies of patients with anxiety-asthenic disorders, 14-day Selank treatment shifted the Th1/Th2 cytokine balance and altered IL-6 gene expression in peripheral blood — establishing a measurable immunomodulatory effect in anxiety disorder patients. In animal stress models, Selank reduced concentrations of pro-inflammatory cytokines (IL-1beta, IL-6, TGF-beta1) while restoring the anti-inflammatory cytokine IL-4 — a pattern suggesting stress-protective immunomodulation rather than simple immunosuppression. This combined neuropsychotropic and immunomodulatory profile is almost unique in pharmacology and is directly relevant to the documented relationship between anxiety disorders and immune dysregulation.
Published Research
Study 1 — Foundational Mechanism: Enkephalinase Inhibition by Selank and Semax
Authors: Kost NV, Sokolov OY, Gabaeva MV, Grivennikov IA, Andreeva LA, Myasoedov NF, Zozulya AA Year: 2001 Journal: Bioorganicheskaya Khimiya (Bioorganic Chemistry) Referenced via: Bioorg Khim. 2001;27(3):180-183
This study established the enkephalinase inhibition mechanism as a central pharmacological activity of Selank — demonstrating that both Selank and the related peptide Semax inhibit enzymes responsible for enkephalin degradation in human serum.
Both Selank and Semax demonstrated potent inhibition of enkephalin-degrading enzymes in human serum — directly establishing the molecular basis for how these peptides extend the half-life and signaling duration of endogenous enkephalins without receptor agonism.
The identification of enkephalinase inhibition provided a mechanistic explanation for both the anxiolytic effects (through amplified delta-opioid receptor signaling from preserved enkephalins) and the observed antiasthenic and cognitive-enhancing effects — linking both the emotional and cognitive dimensions of Selank’s pharmacology to a single molecular mechanism.
This 2001 paper is the foundational mechanistic publication for the enkephalin half-life findings subsequently confirmed in the Zozulya et al. clinical study (2008), where GAD patients showed reduced enkephalin half-life that correlated with disease severity and was normalized by Selank treatment.
Study 2 — Primary Clinical Trial: Selank vs Medazepam in GAD and Neurasthenia
Authors: Zozulya AA, Neznamov GG et al. Year: 2008 Journal: Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova (Journal of Neurology and Psychiatry) PMID: 18454096 Full text: https://pubmed.ncbi.nlm.nih.gov/18454096/
This clinical study was the primary published human efficacy trial for Selank, directly comparing it to medazepam — a classic benzodiazepine anxiolytic — in patients with generalized anxiety disorder and neurasthenia using validated psychiatric assessment instruments.
62 patients with GAD and neurasthenia were studied: 30 received Selank (450 micrograms intranasally 3 times daily for 14 days) and 32 received medazepam. Patient state was assessed using the Hamilton Anxiety Rating Scale, the Zung Self-Rating Anxiety Scale, and the Clinical Global Impressions (CGI) scale.
The anxiolytic effects of Selank were similar to those of medazepam on psychometric scales — establishing comparability to the benzodiazepine benchmark in the core anxiolytic endpoint.
Selank additionally demonstrated antiasthenic and psychostimulant effects not observed with medazepam — clinically meaningful benefits in reducing fatigue and restoring mental energy that benzodiazepines do not produce and typically worsen.
Biological mechanism confirmation: the study measured tau(1/2) leu-enkephalin (enkephalin half-life in blood) and found that GAD and neurasthenia patients had significantly reduced tau(1/2) leu-enkephalin at baseline — correlating with disease duration, anxiety severity, asthenic symptoms, and autonomic disorder severity. Selank treatment increased this parameter, normalizing enkephalin signaling — directly linking the clinical improvement to the enkephalinase inhibition mechanism characterized in laboratory studies.
Selank did not produce the benzodiazepine-typical adverse effects of sedation, cognitive impairment, muscle relaxation, tolerance, or withdrawal — the clinical safety signature that represents Selank’s most significant potential advantage over standard anxiolytic pharmacotherapy.
Study 3 — Immunomodulatory Effects in Anxiety-Asthenic Disorders
Authors: Uchakina ON, Uchakin PN, Myasoedov NF, Andreeva LA, Shcherbenko VE, Mezentseva MV, Gabaeva MV, Sokolov OY, Zozulya AA, Ershov FI Year: 2008 Journal: Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova PMID: 18577961
This study characterized Selank’s immunomodulatory effects in the clinical context of anxiety-asthenic disorders — establishing that its tuftsin-derived immune activity is pharmacologically active in human patients, not merely in laboratory settings.
14-day Selank treatment in patients with anxiety-asthenic disorders produced measurable changes in the Th1/Th2 cytokine balance — shifting the immune profile in a direction associated with reduced inflammatory burden and improved immune regulation.
IL-6 gene expression in peripheral blood was altered by Selank treatment — providing a genomic-level confirmation of the immunomodulatory effect in human patients.
The convergence of anxiolytic and immunomodulatory effects in the same treatment context is directly relevant to the documented relationship between anxiety disorders and immune dysfunction: chronic anxiety is associated with pro-inflammatory cytokine elevation and Th1/Th2 imbalance, and Selank’s ability to address both the neuropsychiatric and immunological dimensions simultaneously represents a pharmacological profile not available from any conventional anxiolytic drug class.
Study 4 — Phenazepam Comparison and Combination Research
Authors: Seredenin SB et al. Year: 2014 Journal: Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova PMID: 25176261
This clinical study compared Selank to phenazepam — a more potent benzodiazepine than medazepam widely used in Russia — and investigated the effects of Selank as combination therapy with phenazepam in anxiety disorders.
Selank demonstrated anxiolytic and mild nootropic effects comparable to phenazepam, with reported anxiolytic persistence approximately one week after cessation of the final dose — a duration that substantially exceeds the half-life of Selank itself, suggesting neuroplastic changes (potentially BDNF-mediated) rather than purely pharmacokinetic activity.
Selank combined with phenazepam produced earlier therapeutic response onset and reduced phenazepam-associated side effects compared to phenazepam monotherapy — supporting a potential adjunctive role for Selank that could reduce the adverse effect burden of benzodiazepine treatment.
The post-cessation persistence of effect — Selank’s anxiolytic activity continuing approximately one week after the last dose — is one of the most clinically distinctive features documented in these studies and distinguishes it from benzodiazepines, whose anxiety-suppressing effects disappear rapidly after cessation.
Study 5 — GABAergic Gene Expression: Molecular Basis of Selank’s Anxiolytic Mechanism
Authors: Kasian A, Kolomin T, Andreeva L, Limborska S, Slominsky P, Shadrina M, Myasoedov N Year: 2016 (published 2017) Journal: Frontiers in Pharmacology Full text: https://pmc.ncbi.nlm.nih.gov/articles/PMC4757669/
This gene expression study investigated Selank’s effects on GABAergic neurotransmission genes in rat brain 1 and 3 hours after administration — providing the molecular mechanistic foundation for the clinical anxiolytic effects observed in human studies.
Selank administration affected mRNA levels of genes encoding GABA receptor subunits, transporters, and proteins involved in GABAergic neurotransmission — demonstrating that Selank produces measurable molecular-level changes in the GABAergic system consistent with its clinical anxiolytic profile.
Selank’s GABAergic gene expression changes differed from those produced by direct GABA administration — establishing that Selank does not act as a simple GABA mimetic but engages a pharmacologically distinct mechanism that converges on GABAergic function through a different molecular entry point.
BDNF emerged as a central regulatory hub in the gene expression network affected by Selank, consistent with the independent findings of hippocampal BDNF upregulation following intranasal Selank — linking the gene expression changes to the neuroplastic dimension of Selank’s pharmacological profile.
Clinical evidence was referenced confirming anxiolytic efficacy comparable to benzodiazepines without their characteristic adverse effect profile — situating the molecular findings in a clinically validated context.
Study 6 — BDNF, Memory, and Neuroprotection: Selank in Ethanol-Induced Cognitive Impairment
Authors: Kolik LG et al. Year: 2019 Journal: Bulletin of Experimental Biology and Medicine PMID: 31625062 Full text: https://pubmed.ncbi.nlm.nih.gov/31625062/
This study examined Selank’s effects on memory, cognitive function, and BDNF levels in rats exposed to chronic ethanol — extending the BDNF mechanism into a neuroprotection and age-related cognition context.
Selank (0.3 mg/kg for 7 days intraperitoneally) produced a cognitive-stimulating effect in 9-month-old rats not exposed to ethanol (P less than 0.05) and prevented the formation of ethanol-induced memory and attention disturbances developing during alcohol withdrawal (P less than 0.01) in the object recognition test.
Selank prevented ethanol-induced increases in BDNF content in the hippocampus and frontal cortex (P less than 0.05) — demonstrating that Selank’s effect on BDNF is regulatory rather than simply elevatory. In alcohol-exposed animals, where ethanol abnormally elevated hippocampal BDNF as a pathological response, Selank normalized BDNF back toward control levels rather than further elevating it.
These results confirmed involvement of the neurotrophin mechanism related to BDNF production in Selank’s effects on memory and cognition — establishing BDNF modulation as mechanistically relevant to both the cognitive and protective dimensions of Selank’s pharmacological profile, not merely to its anxiolytic activity.
Selank Compared to Semax — Sibling Compounds from the Same Institute
Selank and Semax are frequently discussed together as sibling neuropeptides developed by the same research program at the Institute of Molecular Genetics. Understanding their relationship helps position each correctly.
Semax is an ACTH(4-10) analog — a synthetic heptapeptide derived from the adrenocorticotropin (ACTH) sequence rather than from tuftsin. Semax’s primary pharmacological profile centers on BDNF and neurotrophin upregulation, neuroprotection in ischemia models, and cognitive enhancement. Semax shares with Selank the enkephalinase inhibition mechanism identified by Kost et al. 2001, which contributes overlapping components to each compound’s nootropic effects.
Where Selank and Semax most clearly diverge is in their primary research indications: Selank is approved and primarily studied in Russia for anxiety disorders (its GABAergic and enkephalinergic anxiolytic mechanisms being its defining profile), while Semax is registered for vascular brain conditions, including stroke and traumatic brain injury, with the neuroprotective and neurotrophin-mediated mechanisms being its defining profile. The two compounds are complementary research tools for different aspects of neuropeptide pharmacology but should not be treated as interchangeable.
Selank and the Benzodiazepine Comparison — What the Evidence Actually Says
The comparison between Selank and benzodiazepines is the most clinically significant research claim in this profile and deserves careful, accurate framing.
The published evidence supports: Selank at 450 micrograms intranasally three times daily for 14 days produced Hamilton Anxiety Scale reductions comparable to medazepam in a 62-patient study (Zozulya et al., 2008). Selank produced anxiolytic effects comparable to phenazepam in a separate clinical investigation (Seredenin et al., 2014). Selank did not produce benzodiazepine-type adverse effects (sedation, amnesia, tolerance, dependence, withdrawal) in published clinical experience.
The evidence does not support: that Selank has been evaluated in large multicenter randomized controlled trials with rigorous blinding and adequate power comparable to FDA registration trials; that Selank has been compared against first-line anxiety disorder treatments (SSRIs, SNRIs, buspirone) in registered controlled trials; or that the regulatory approval granted in Russia reflects the same evidence standard as FDA or EMA approval.
These limitations are honest and appropriate to acknowledge. The Russian clinical research on Selank is not trivial — it includes validated psychometric assessments, active comparator designs, and biological mechanistic measurements — but it does not rise to the western regulatory standard that would allow FDA approval claims, and independent replication outside the originating research context is limited.
Current Research Status
Selank is registered in Russia as a 0.15% intranasal pharmaceutical for generalized anxiety disorder and neurasthenic conditions. No FDA or EMA approval exists. No Western Phase 1-3 clinical trial is registered as of this compilation. Research continues in Russia and related academic centers on the mechanisms of tuftsin analogs in anxiety, cognition, neuroplasticity, and neuroimmune interactions. Interest in the compound outside Russia has grown substantially as researchers seek anxiolytic mechanisms without benzodiazepine-type adverse effects.
Reconstitution Note
Selank is supplied as lyophilized powder. Bacteriostatic water is the standard reconstitution solvent for research use. The registered Russian pharmaceutical formulation is a 0.15% intranasal solution (1.5 mg/mL). Selank dissolves readily in aqueous solution. Protect from light. Always confirm the recommended solvent against the specific lot datasheet before reconstitution.
In-Use Period and Storage
Before Reconstitution — Lyophilized Powder
Rogue Compounds stores all products refrigerated prior to shipping to maintain compound integrity from production through to delivery. Upon receipt researchers should store vials at 2 to 8 degrees Celsius immediately. Keep vials sealed, dry, and away from direct light until ready for use. Do not freeze. Repeated freeze-thaw cycling has been documented in peer-reviewed pharmaceutical formulation literature to accelerate structural degradation even in dry powder form, potentially compromising molecular integrity and experimental reproducibility.
Why We Refrigerate Instead of Freeze
Freezing and thawing introduces mechanical and osmotic stress at the molecular level. Published pharmaceutical research identifies freeze-thaw cycling as a significant risk factor for loss of structural integrity in peptides and protein-based compounds. To protect compound quality at every stage of handling and fulfillment, Rogue Compounds maintains refrigerated rather than frozen cold chain storage throughout the entire process.
After Reconstitution — Liquid Solution
Store reconstituted solutions refrigerated at 2 to 8 degrees Celsius immediately after preparation. Protect from light. Avoid repeated freeze-thaw cycles. Use within the timeframe recommended for the individual compound. Label each aliquot with the compound name, concentration, date of reconstitution, and diluent used. Discard any solution that shows visible particulate matter, discoloration, or signs of contamination.
Note: Storage and in-use recommendations on this page are provided as general laboratory guidance based on standard peptide handling practices documented in peer-reviewed pharmaceutical literature. Researchers should always refer to the individual compound’s published research literature and datasheet for any specific requirements. All products sold by Rogue Compounds are intended strictly for in-vitro laboratory research use only.
Available from Rogue Compounds
View the Selank product page: https://roguecompounds.com/product/selank/