Selank Peptide Guide

Selank is a synthetic seven-amino-acid peptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro (TKPRPGP). Its formal designation is TP-7. The first four residues (Thr-Lys-Pro-Arg) replicate tuftsin, a naturally occurring tetrapeptide cleaved from the Fc region of immunoglobulin G that stimulates macrophage and neutrophil activity. The final three residues (Pro-Gly-Pro) are the same enzymatic shield used in Semax, designed to protect the parent peptide from rapid degradation.

What makes Selank pharmacologically unusual is the distance between its parent molecule and its primary clinical application. Tuftsin is an immune peptide with no known anxiolytic function. Yet when Myasoedov’s team at the Institute of Molecular Genetics stabilised it with Pro-Gly-Pro and tested the resulting heptapeptide, they found pronounced anxiolytic and nootropic properties alongside the expected immunomodulatory effects. Selank does not fit neatly into any existing drug category: it is not a benzodiazepine, not an SSRI, not a buspirone-type compound. It produces benzodiazepine-level anxiety reduction through a mechanism that does not produce sedation, tolerance, or physical dependence.

Property	Detail
Full name	Selank (Cеланк) / TP-7
Sequence	Thr-Lys-Pro-Arg-Pro-Gly-Pro (TKPRPGP)
Parent molecule	Tuftsin (Thr-Lys-Pro-Arg), IgG Fc fragment tetrapeptide
CAS number	129954-34-3
Molecular formula	C33H57N11O9
Molecular weight	751.887 Da
Route of administration	Intranasal (primary)
Russian formulation	0.15% intranasal solution
Developer	Institute of Molecular Genetics, Russian Academy of Sciences (Moscow)
Lead researcher	N.F. Myasoedov
Russian approval	2009 (authorisation LRS-003338/09)

The bottom line: Selank is a tuftsin-derived heptapeptide that became an anxiolytic – an immune peptide that turned out to have potent CNS effects, producing benzodiazepine-level anxiety reduction without benzodiazepine-class side effects.

Selank does not work through a single receptor. It modulates at least four distinct neurochemical systems simultaneously, which is both its pharmacological strength and the reason it defies clean classification.

GABA-A Receptor Modulation

The most clinically significant mechanism is Selank’s modulation of GABA-A receptors. Unlike benzodiazepines, which bind directly to the benzodiazepine allosteric site on the GABA-A receptor and produce potent but sedating anxiolysis, Selank modulates GABAergic neurotransmission at a different site. The practical consequence: comparable anxiety reduction without the sedation, muscle relaxation, cognitive impairment, tolerance development, or withdrawal syndrome that define the benzodiazepine class.

Volkova, Shadrina, Kolomin, and colleagues (Frontiers in Pharmacology, 2016) demonstrated that Selank administration altered the expression of 45 genes involved in GABAergic neurotransmission in the rat frontal cortex within one hour. This rapid transcriptomic response at the GABA system level provides a molecular basis for the clinically observed anxiolytic onset.

Enkephalinase Inhibition

Selank inhibits enzymes that degrade endogenous enkephalins – the body’s own opioid peptides involved in mood regulation, stress buffering, and pain modulation. In patients with generalised anxiety disorder, leu-enkephalin levels are measurably reduced, and this deficit correlates with disease severity. The Zozulya 2008 clinical trial found that Selank treatment produced measurable increases in leu-enkephalin levels that correlated with anxiety score improvements – a neurochemical shift absent in the benzodiazepine comparator group.

Serotonin and BDNF

Selank influences serotonin metabolism in the hypothalamus and upregulates BDNF expression in the hippocampus. These effects are secondary to the primary GABAergic mechanism but contribute to the compound’s nootropic profile – the cognitive clarity and improved memory consolidation reported alongside anxiety reduction. This BDNF-mediated neuroplastic effect develops over days to weeks of treatment and distinguishes Selank from conventional anxiolytics that impair rather than preserve cognition.

Immunomodulation

Selank retains the immunomodulatory properties of its parent molecule tuftsin. Uchakina and colleagues (Bulletin of Experimental Biology and Medicine, 2008, PMID 18683560) demonstrated that Selank significantly modulated IL-6 production in human peripheral blood mononuclear cells. Kolomin and colleagues (Molecular Immunology, 2014) documented the temporal dynamics of inflammation-related gene expression changes under Selank, showing effects on 34 genes influencing cytokines, chemokines, and their receptors. Ershov and colleagues demonstrated Selank’s modulation of interferon-related gene expression. These dual neurological-immunological effects occur at standard anxiolytic doses, providing an unusual pharmacological profile that no Western-approved drug replicates.

Tuftsin Biology and the Spleen Connection

To fully understand Selank’s immunological significance, it helps to understand tuftsin’s role in the body. Tuftsin (Thr-Lys-Pro-Arg) was first described by Victor Najjar at Tufts University in 1970 as a naturally occurring phagocytosis-stimulating peptide. It resides at positions 289-292 of the immunoglobulin G heavy chain Fc domain and requires two sequential enzymatic cleavages to become active: first, a splenic endocarboxypeptidase nicks the heavy chain at the Arg-Glu bond between residues 292 and 293; then leukokininase, present on the outer membrane of phagocytic cells, cleaves at the amino end of threonine between residues 288 and 289. The released free tuftsin stimulates phagocytosis, natural killer cell activity, macrophage function, and reactive oxygen species production in neutrophils.

The clinical significance of this biology becomes apparent after splenectomy. Because the first enzymatic cleavage depends on a splenic enzyme, removing the spleen causes tuftsin deficiency. Constantopoulos, Najjar, and colleagues (American Journal of Diseases of Children, 1973) demonstrated defective phagocytosis due to tuftsin deficiency in splenectomised subjects. Spirer and colleagues (British Medical Journal, 1977) confirmed decreased tuftsin concentrations in splenectomy patients. This deficiency contributes to the well-documented risk of overwhelming post-splenectomy infection (OPSI), which carries mortality rates described in the literature as up to 600 times greater than the general population for septic events.

The tuftsin-immune axis extends beyond splenectomy. A 1991 Lancet study demonstrated that patients with AIDS had significantly lower tuftsin activity than healthy volunteers, correlating with functional hyposplenism. The prevalence of functional hyposplenism in HIV-positive patients was estimated at 36% using pitted erythrocyte counting, and tuftsin activity correlated inversely with splenic dysfunction. Tuftsin deficiency may therefore contribute to the susceptibility to bacterial infection in symptomatic HIV-positive individuals beyond the well-characterised CD4 depletion.

Selank, as a stabilised synthetic analog of tuftsin, exists within this broader immunological context. While the Russian clinical programme focused almost exclusively on anxiety and cognitive applications, tuftsin’s well-characterised role in innate immune defence raises questions about whether Selank’s immunomodulatory properties might have significance in immune-compromised populations. No clinical investigation of this possibility has been published, but the theoretical basis is grounded in decades of tuftsin biology documented in Western immunology literature.

The bottom line: Selank’s multi-target mechanism – GABA modulation, enkephalin stabilisation, serotonin influence, and immune regulation – produces anxiolysis without sedation, a combination that no single-mechanism Western anxiolytic achieves.

Selank has more human clinical trial data than most research peptides. Russian trials have enrolled over 250 patients across multiple studies comparing Selank to benzodiazepines and placebo. This is an unusually robust evidence base for a compound in the nootropic peptide category, though all trials originate from Russian institutions.

Selank vs Medazepam (Zozulya 2008)

The foundational clinical study was conducted by Zozulya, Neznamov, Siuniakov, and colleagues, published in Zhurnal Nevrologii i Psikhiatrii im. S.S. Korsakova (2008, PMID 18454096). This trial enrolled 62 patients with generalised anxiety disorder and neurasthenia, comparing Selank (450 mcg intranasally three times daily, total 1,350 mcg/day for 14 days) against medazepam, a benzodiazepine.

Anxiolytic effects were similar between groups as measured by Hamilton Anxiety Rating Scale, Zung Self-Rating Anxiety Scale, and Clinical Global Impression scale. Selank additionally demonstrated antiasthenic and psychostimulant effects that were not observed with medazepam. The study also revealed that patients with GAD had reduced leu-enkephalin levels, and that Selank treatment restored these levels in correlation with clinical improvement.

Selank vs Phenazepam (Seredenin 2014)

A second comparison trial by Seredenin and colleagues (Zhurnal Nevrologii i Psikhiatrii, 2014) studied 60 patients with phobic-anxiety and somatoform disorders. Selank produced clear anxiolytic and mild nootropic effects comparable to phenazepam, a potent benzodiazepine widely prescribed in Russia. Crucially, the anxiolytic effect carried over for approximately one week after the last dose, suggesting neuroplastic changes rather than purely acute receptor effects.

Selank Added to Phenazepam (Seredenin 2015)

A 2015 study by the same group enrolled 70 patients and tested adding Selank to phenazepam treatment. The combination produced earlier therapeutic response and measurably fewer phenazepam-related side effects (sedation, cognitive impairment, emotional flatness) compared to phenazepam alone. This study suggests Selank may have benzodiazepine-sparing properties – allowing lower effective doses of benzodiazepines when used in combination.

Placebo-Controlled Data

A double-blind, placebo-controlled trial in 60 patients with GAD tested Selank at 300 mcg intranasally three times daily for 14 days. Selank reduced Hamilton Anxiety Scale scores by 47% at Day 14, compared to 34% in the placebo arm – a statistically significant difference. A parallel arm comparing Selank to medazepam found equivalent anxiolytic efficacy with superior cognitive performance: medazepam produced measurable slowing on reaction time and attention tasks, while Selank did not.

Immunomodulatory Evidence

Uchakina, Uchakin, and Myasoedov (2008) measured immune markers in patients with anxiety-asthenic disorders during a 14-day Selank course, documenting shifts in Th1/Th2 cytokine balance and IL-6 modulation. A separate 24-subject trial tested Selank in healthy volunteers during influenza season, with the Selank group showing enhanced interferon production. A 2020 animal study (PMID 32621722) demonstrated Selank’s ability to reduce IL-1beta, IL-6, TNF-alpha, and TGF-beta1 under social stress conditions.

A study on the temporal dynamics of inflammation-related genes (Medvedeva and colleagues, published in Molecular Immunology) added granularity to this picture. Single intraperitoneal injection of Selank in mice caused a significant 3-fold decrease in complement component C3 mRNA within 30 minutes. Caspase-1 (Casp1) expression showed a wave-like alteration pattern over the following hours. The IL-2 receptor gamma chain (Il2rg) and the chemokine receptor XCR1 both showed significant early-timepoint alterations. These effects were rapid (detectable within half an hour), transient (following oscillatory patterns rather than sustained upregulation or downregulation), and partially replicated by the Gly-Pro fragment alone, suggesting the C-terminal portion of the molecule contributes independently to the immunomodulatory response.

Other Preclinical Findings

Konstantinopolsky and colleagues (Bulletin of Experimental Biology and Medicine, 2022) demonstrated that Selank attenuated aversive signs of naloxone-precipitated morphine withdrawal in rats, suggesting a potential role in opioid withdrawal management through its enkephalin-stabilising mechanism. Kasian and colleagues showed that Selank enhanced the anxiolytic effect of diazepam in unpredictable chronic mild stress models, providing further evidence for benzodiazepine-potentiating properties.

Antiviral Activity and Fragment Pharmacology

An aspect of Selank’s pharmacology that receives almost no coverage in English-language peptide content is its antiviral activity. Ershov, Uchakin, and Uchakina (published in Zhurnal Mikrobiologii, Epidemiologii i Immunobiologii, 2009) tested Selank against influenza A/Aichi 2/68 (H3N2) both in cell culture and in vivo in mice. The compound showed pronounced antiviral effects in both systems. When added to cell cultures 24 hours before viral inoculation (a preventive scheme), Selank completely suppressed viral reproduction. In vivo, the preventive administration scheme produced the highest survival rates among infected laboratory animals. The mechanism appeared to involve selective induction of interferon-alpha gene expression without affecting IL-4, IL-10, or TNF-alpha, suggesting Selank modulates the Th1/Th2/Treg cytokine equilibrium towards an antiviral response profile.

Andreeva, Nagaev, Mezentseva, and Myasoedov (Doklady Biological Sciences, 2010) then mapped antiviral activity to individual structural fragments of Selank. They tested each possible subfragment against a panel of viruses: human influenza A/Aichi 2/68 (H3N2), human influenza B/Ohio 01/05, avian influenza H5N1, herpes simplex virus types 1 and 2, cytomegalovirus, and murine encephalomyocarditis virus. The tetrapeptide Arg-Pro-Gly-Pro exhibited the highest antiviral activity across the full viral panel, with effects comparable to reference antiviral preparations. The dipeptide Gly-Pro was identified as the minimum amino acid sequence (pharmacophore) retaining antiviral activity. This fragment mapping is significant because it demonstrates that Selank’s antiviral properties are not simply inherited from tuftsin’s immune-stimulating activity – they map to the C-terminal Pro-Gly-Pro region and its fragments, the same stabilisation tail used in Semax.

The bottom line: Selank’s antiviral properties are well-documented in the Russian literature but essentially unknown in English-language peptide content. The fragment mapping data suggests these properties arise from the C-terminal PGP portion of the molecule rather than from the tuftsin-derived N-terminus, creating an unexpected functional separation: the tuftsin fragment drives anxiolytic and immunomodulatory effects, while the PGP fragment drives antiviral activity.

Study	Evidence Tier	Key Result
Zozulya 2008 vs medazepam (n=62)	Human, active-controlled	Equivalent HAM-A reduction + antiasthenic effects medazepam lacked
Seredenin 2014 vs phenazepam (n=60)	Human, active-controlled	Anxiolytic + nootropic, 1-week carryover post-cessation
Seredenin 2015 added to phenazepam (n=70)	Human, combination	Earlier response, fewer benzo side effects
Placebo-controlled GAD (n=60)	Human, double-blind RCT	47% HAM-A reduction vs 34% placebo (p<0.05)
Uchakina 2008 immune markers (patients)	Human, observational	IL-6 modulation, Th1/Th2 cytokine balance shifts
Volkova 2016 GABAergic genes (rats)	Preclinical (rodent)	45 GABAergic genes altered in frontal cortex within 1 hour
Konstantinopolsky 2022 morphine withdrawal (rats)	Preclinical (rodent)	Attenuated aversive withdrawal signs
Ershov 2009 influenza A/H3N2 (in vitro + mice)	Preclinical (in vitro + rodent)	Complete suppression of viral reproduction in preventive scheme; IFN-alpha induction
Andreeva 2010 fragment mapping (in vitro)	Preclinical (in vitro)	Arg-Pro-Gly-Pro fragment had highest antiviral activity across 7 virus types
Medvedeva inflammation gene dynamics (mice)	Preclinical (rodent)	3-fold C3 mRNA decrease within 30 min; wave-like Casp1 alterations

The bottom line: Selank has stronger human evidence than nearly any compound in the research peptide category, with multiple clinical trials totalling over 250 patients demonstrating anxiolytic efficacy comparable to benzodiazepines without their defining side effects – but all data originates from Russian-affiliated research groups.

Selank’s regulatory trajectory differs from Semax in one critical respect: while Semax has a confirmed PCAC review date (July 24, 2026), Selank was removed from Category 2 earlier (September 2024) but has no scheduled PCAC date. It was referred to the PCAC process but has not been individually placed on any meeting agenda.

Jurisdiction	Status	Detail
Russia	Approved	Since 2009 (LRS-003338/09) for GAD, neurasthenia, adjustment disorders. 0.15% nasal solution
United States (FDA)	Not approved	Category 2 Sept 2023 – removed Sept 20, 2024 (nominator withdrew). Referred to PCAC but no scheduled review date. Not DEA-scheduled
United Kingdom (MHRA)	Not licensed	Not controlled under Misuse of Drugs Act. Peptides generally exempt from Psychoactive Substances Act 2016
Australia (TGA)	Not approved	Not scheduled under the Poisons Standard. Not TGA-registered
WADA	Likely prohibited	Not individually named but likely caught by S0 blanket prohibition on unapproved substances

The September 2024 removal from Category 2 occurred when the nominator withdrew Selank acetate (TP-7) from the 503A nomination process. This was a procedural step that removed the regulatory hold but did not grant compounding permission. Until Selank receives a formal PCAC review and a positive recommendation followed by FDA rulemaking, it remains outside the legal compounding framework in the United States. For broader context on peptide legality, see our guides for the US, the UK and Australia.

The bottom line: Selank sits in a regulatory gap – removed from Category 2 but not yet scheduled for PCAC review, leaving it in a limbo that neither prohibits nor permits compounding in the US.

Selank’s safety profile is one of its most consistently reported strengths. Across all published clinical trials, including courses up to 28 days, no sedation, cognitive impairment, tolerance, physical dependence, or withdrawal symptoms have been documented. This is the defining clinical advantage over benzodiazepines and what drove the Russian regulatory approval.

Reported side effects are minimal: mild nasal irritation during intranasal administration and, rarely, mild headache. No serious adverse events have been published in any Selank trial. The Russian pharmaceutical record extends from 2009 through to present-day clinical use with no post-marketing safety signals.

Because Selank retains tuftsin’s immunomodulatory properties, there is a theoretical concern about its use in individuals with active autoimmune conditions. The immune stimulation (enhanced phagocyte activity, interferon modulation) that is beneficial during infection recovery or high-stress periods could theoretically aggravate autoimmune pathology. No clinical data directly supports or refutes this concern.

The bottom line: Selank has a remarkably clean safety profile across its clinical trial history, with no sedation, dependence, or cognitive impairment – the exact properties that make benzodiazepines problematic – but the total safety dataset is small by Western pharmaceutical standards.

Every clinical trial and nearly every preclinical study on Selank originates from the Institute of Molecular Genetics of the Russian Academy of Sciences or the Institute of Pharmacology of the Russian Academy of Medical Sciences. The lead researcher, N.F. Myasoedov, is both the compound’s developer and a co-author on the majority of published studies. The clinical investigators (Zozulya, Seredenin) work within the Russian Academy system.

This is an identical concentration problem to the one affecting Semax: deep, consistent evidence from one research ecosystem with no independent Western replication. The Selank clinical trials are well-designed by the standards of their era and setting (active comparators, validated outcome measures, published in indexed Russian journals), but no Western-standard registration trial has been attempted.

The bottom line: Selank’s clinical evidence is substantial for a research peptide but entirely concentrated in Russian institutions with direct programme involvement – the same limitation that affects every compound from this laboratory.

Semax is Selank’s sister compound from the same laboratory, using the same Pro-Gly-Pro stabilisation design but built on ACTH(4-7) rather than tuftsin. Where Selank is calming and anxiolytic through GABAergic modulation, Semax is activating and cognitively stimulating through BDNF upregulation and dopaminergic sensitisation. The two compounds have complementary, non-overlapping mechanisms and are frequently combined in Russian clinical practice and in the research community. A head-to-head comparison is covered in our Semax vs Selank comparison (forthcoming).

N-Acetyl Selank is an acetylated variant designed to extend metabolic stability through protection from aminopeptidase-mediated degradation. The pharmacological profile is expected to be qualitatively similar to unmodified Selank but with enhanced blood-brain barrier penetration and longer effective duration. No independent clinical data exists for this variant.

For how Selank fits within the broader landscape of cognitive and anxiolytic peptides, see our Nootropic and Neuropeptide Compounds hub page. For verifying the identity and purity of research peptides, see our COA guide.

What is Selank derived from?

Selank is derived from tuftsin, a naturally occurring tetrapeptide (Thr-Lys-Pro-Arg) cleaved from the Fc region of immunoglobulin G. Tuftsin was first identified at Tufts University in 1983 and functions as an immune-stimulating peptide. The addition of a Pro-Gly-Pro C-terminal tail stabilised the molecule and revealed anxiolytic properties not present in the parent peptide.

Does Selank cause sedation or dependence?

No. Clinical trials up to 28 days show no sedation, cognitive impairment, tolerance, physical dependence, or withdrawal symptoms. This is the defining difference between Selank and benzodiazepines, which produce all of these effects. Selank is not a GABA-A agonist and does not produce the receptor downregulation that drives benzodiazepine dependence.

Is Selank approved anywhere?

Selank is approved in Russia (since 2009) and Ukraine for generalised anxiety disorder, neurasthenia, and adjustment disorders. It is available as a 0.15% intranasal solution for approximately $10-20 per bottle in Russian pharmacies. It is not approved in any Western country.

What is Selank’s FDA status?

Selank acetate (TP-7) was placed on FDA Category 2 in September 2023 and removed on September 20, 2024 when the nominator withdrew. It was referred to the PCAC process but, unlike Semax, has not been individually scheduled for review at any announced meeting. It is not DEA-scheduled and is not a controlled substance in the United States.

How does Selank compare to benzodiazepines?

In Russian clinical trials, Selank matched both medazepam and phenazepam for anxiety reduction as measured by standard rating scales (Hamilton, Zung, CGI). The key differences: Selank produced no sedation, no cognitive impairment, no tolerance, and no withdrawal, while adding antiasthenic and mild nootropic effects the benzodiazepines lacked. When added to phenazepam, it reduced the benzodiazepine’s side effects while accelerating therapeutic response.

Can Selank and Semax be used together?

The Selank-Semax combination is one of the most established peptide pairings in both Russian clinical practice and the research community. The two compounds act through different and complementary mechanisms: Selank provides calming anxiolysis through GABAergic modulation, while Semax provides cognitive stimulation through BDNF-mediated neuroplasticity. No controlled combination study has been published, but the pairing has extensive observational use.

What is the difference between Selank and N-Acetyl Selank?

N-Acetyl Selank has an acetyl group added to the N-terminal threonine residue, designed to protect against aminopeptidase degradation and extend the effective half-life beyond the approximately 2-3 minutes reported for unmodified Selank. The pharmacological profile is expected to be qualitatively similar but with potentially improved CNS bioavailability. No independent clinical data exists for N-Acetyl Selank – it is a grey-market research variant with no Russian regulatory approval.