Peptides & growth hormone

Selank

Updated · 21 sources · Editorial policy

Selank (research code TP-7) is a synthetic seven-amino-acid peptide developed in Russia as an anti-anxiety drug. It is built from tuftsin, a short immune-system peptide that occurs naturally in the body, with a three-amino-acid tail added to make it last longer. It is studied mainly as an anxiolytic (anti-anxiety agent) and, in animals, for effects on memory and learning.

The single most important fact: the human evidence is thin. It consists of a handful of small Russian clinical studies of anxiety disorders, published in Russian, whose abstracts report no placebo group or blinding. Selank is not approved by the FDA. It is sold online as an injectable powder or nasal spray, and to US consumers as a dietary supplement, outside the regulated drug supply.

This page summarizes what the published studies and regulators report. It is for education only and is not medical advice.

Property Detail
Class Synthetic regulatory peptide; tuftsin analog
Other names TP-7; selank acetate
Structure 7 amino acids; formula C₃₃H₅₇N₁₁O₉, molecular weight 751.9 g/mol (PubChem)
Routes studied Intranasal and injected in animal studies; injected in one human imaging study
Proposed mechanisms Modulates GABA-A receptor binding and slows breakdown of enkephalins (lab and animal data)
Human half-life No published human pharmacokinetic data found
Human evidence Small comparisons with benzodiazepines in anxiety disorders (n = 60–70 per study)
US status Not FDA-approved; FDA lists it among bulk substances with safety concerns for compounding
WADA status Not named on the 2026 Prohibited List

What it is

Tuftsin is a four-amino-acid fragment of the heavy chain of human immunoglobulin G (IgG, the most common antibody). Selank extends tuftsin at one end with three more amino acids, a proline–glycine–proline unit. Russian researchers added this tail to improve the peptide’s metabolic stability and lengthen its action (Volkova et al., Front Pharmacol 2016; Kasian et al., Behav Neurol 2017). PubChem lists it under CID 11765600 with the synonyms TP-7 and Selanc (PubChem).

Selank was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences together with the V.V. Zakusov Research Institute of Pharmacology (Volkova et al., 2016). Early rat work in the 1990s reported that TP-7 had stronger anti-anxiety and stimulant-like effects than tuftsin itself (Seredenin et al., Eksp Klin Farmakol 1995).

Its sibling peptide Semax is another Russian heptapeptide that ends in the same proline–glycine–proline tail but has a different starting fragment (Kost et al., Bioorg Khim 2001). Researchers describe Semax as a nootropic (cognition-targeting) agent and selank as an anxiolytic (Panikratova et al., Dokl Biol Sci 2020). The two have been found together in seized products, discussed below.

Proposed mechanisms

All mechanism data come from cell, tissue and animal studies:

  • GABA-A receptors. In binding studies on brain-cell membranes, selank changed the binding of GABA (the brain’s main calming neurotransmitter) in a way the authors interpreted as positive allosteric modulation, the same general mechanism as benzodiazepines but at a site that appears not to be identical (Vyunova et al., Protein Pept Lett 2018).
  • Enkephalin breakdown. In human serum in the test tube, selank inhibited the enzymes that break down enkephalins (natural opioid peptides), with an IC50 of 20 µM (Kost et al., Bioorg Khim 2001). In mice, selank reduced anxiety-like behavior and lengthened the plasma half-life of leu-enkephalin in BALB/c mice, but had neither effect in C57Bl/6 mice (Sokolov et al., Bull Exp Biol Med 2002).
  • Gene expression. In the rat frontal cortex, selank changed the expression of 45 of 84 neurotransmission-related genes, including GABA receptor genes, within 1 hour (Volkova et al., 2016).

How it behaves in the body

There are no published human pharmacokinetic studies, so its human half-life, bioavailability and duration of action are not known. The available data are from animals and test-tube work:

Finding Model Source
Broken down mainly into a five-amino-acid fragment, a three-amino-acid fragment and two dipeptides Blood plasma; brain tissue after intranasal dosing in animals Zolotarev et al., Bioorg Khim 2006
Intranasal dosing was the best of four routes for getting the peptide into the brain Rats; intraperitoneal, intranasal, intragastric and intravenous compared Ashmarin et al., Bioorg Khim 2008
High uptake into stomach tissue by every route Rats Ashmarin et al., 2008

About the half-life. We could not find any published measurement of selank’s half-life in people. Any half-life figure quoted for it should be treated as unverified.

Regulatory status

  • United States. Selank is not an FDA-approved drug. FDA placed “selank acetate (TP-7)” in category 2 of bulk drug substances nominated for compounding, the group FDA flags as potentially presenting significant safety risks. FDA cited a risk of immunogenicity (triggering an immune response) from aggregation and peptide-related impurities and said it “lacks important information” on safety in humans. FDA’s current page lists selank among category 2 nominations that were later withdrawn by the nominators (FDA, category 2 bulk drug substances).
  • Sale as a supplement. A 2021 pharmacology review described selank and phenibut as “poorly studied Russian drugs” sold to US consumers as dietary supplements (Doyno and White, J Clin Pharmacol 2021).
  • Russia. Selank was developed and clinically studied in Russia. We could not access the Russian state drug register to confirm its current registration status, so we do not state it here.
  • Controlled-substance status. Selank is not a scheduled anabolic steroid and is not named in 21 CFR 1308.13.
  • Sport. Selank is not named on the WADA 2026 Prohibited List. The list’s S0 class bans, at all times, any substance with “no current approval by any governmental regulatory health authority for human therapeutic use.” Whether S0 covers selank therefore depends on its approval status outside the US, which we could not verify. Athletes should check with their anti-doping organization.

What the research shows

Anxiety disorders in people

All human efficacy data come from small Russian studies published in Russian. Their English abstracts describe active-comparator or add-on designs. They do not report a placebo group, blinding or randomization, and the abstracts do not give effect sizes.

Study Patients Comparison Reported result
Zozulia et al., 2008 62 with generalized anxiety disorder (GAD) or neurasthenia Selank (n = 30) vs medazepam, a benzodiazepine (n = 32) Similar anti-anxiety effect; selank also had “antiasthenic” (anti-fatigue) and stimulant-like effects
Medvedev et al., 2014 60 with phobic-anxiety and somatoform disorders Selank vs phenazepam, a benzodiazepine “Pronounced” anti-anxiety and mild nootropic effects; the effect lasted a week after the last dose
Medvedev et al., 2015 70 with anxiety-phobic, hypochondriac and somatoform disorders Phenazepam alone (n = 30) vs phenazepam plus selank (n = 40) Faster response on the Hamilton scale and fewer phenazepam side effects with the combination

The 2015 add-on study reported that adding selank reduced several benzodiazepine side effects:

  • attention and memory problems;
  • sedation and longer sleep;
  • fatigue and emotional blunting;
  • sexual problems and orthostatic symptoms (problems on standing up).

These findings have not been replicated outside the developer’s research network. Several authors on the clinical papers are also co-authors of the peptide’s development work. The trials compared selank with benzodiazepines rather than placebo, so they cannot show how much of the improvement is due to selank itself.

Immune effects

In patients with GAD and neurasthenia given selank for 14 days, serum markers of the Th1/Th2 cytokine balance (two branches of immune signaling) shifted. In cell culture, selank suppressed IL-6 gene expression in blood cells from patients with depression, although IL-6 levels in the culture rose (IL-6 is an inflammatory messenger) (Uchakina et al., 2008). The clinical meaning of these changes is not known.

Brain imaging in healthy volunteers

A study in 52 healthy adults used resting-state functional MRI before and 5 and 20 minutes after selank, Semax or placebo. Selank changed functional connectivity between the right amygdala (a region involved in fear and anxiety) and parts of the right temporal lobe (Panikratova et al., Dokl Biol Sci 2020). The study measured brain connectivity, not anxiety or cognitive performance.

Animal studies

Most selank research is in rodents. Examples:

Results like these cannot be assumed to apply to people.

Muscle, recovery and performance

In a PubMed search, we found no human or animal studies of selank on muscle, tissue repair, body composition or athletic recovery. A 2026 review of therapeutic peptides grouped selank with Semax and Dihexa as “neuroactive” peptides and noted a current lack of clinical trials for the peptides it reviewed (Rahman et al., JAAOS Glob Res Rev 2026).

Side effects and risks

Limited safety data

The Russian studies describe selank as well tolerated, but they were small, short and not designed to detect uncommon harms. No long-term safety studies have been published. FDA said it lacks important information on the safety of selank acetate in humans (FDA).

Immunogenicity and impurities

FDA’s main stated concern is that peptide products made outside approved manufacturing can aggregate or contain peptide-related impurities. Both can provoke an immune reaction, depending on the route of administration.

Interactions with sedatives

Selank acts on the GABA system in animal and lab studies. A clinical-pharmacology review grouped it with GABA-acting sedative-hypnotics and noted that when drugs in this group are used in high doses or with other sedatives, respiratory depression, coma and death have occurred (Doyno and White, 2021). In rats, selank enhanced the effect of diazepam (Kasian et al., 2017). No human interaction studies have been published.

Product quality

Sciensano, Belgium’s public-health laboratory, analyzed two suspicious seized preparations in 2017 and 2018 and found that they contained selank and Semax. The authors noted these peptides had not completed clinical trials and were freely sold online as injectable powders and nasal sprays, and they developed a lab method to identify them (Vanhee et al., Drug Test Anal 2020). Such products are sold outside approved manufacturing and regulatory quality control.

Key takeaways

  • A tuftsin-derived anxiolytic peptide. Selank is a seven-amino-acid synthetic analog of an immune peptide, developed in Russia for anxiety.
  • Human evidence is small and uncontrolled. Three Russian studies of 60–70 patients compared it with or added it to benzodiazepines; none reported a placebo group.
  • Mechanism data come from animals and lab work. Proposed actions include GABA-A receptor modulation and slowing enkephalin breakdown.
  • No human half-life is published. Pharmacokinetic data come only from rat and plasma studies.
  • Not approved in the US. FDA flagged selank acetate for immunogenicity and impurity risks and says human safety data are lacking.
  • No evidence for muscle or recovery. No studies have tested selank on muscle, tissue repair or athletic performance.

Sources

  1. National Center for Biotechnology Information. PubChem Compound Summary for CID 11765600, Selank. PubChem.
  2. 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. PubMed.
  3. Kasian A, Kolomin T, Andreeva L, et al. Peptide Selank enhances the effect of diazepam in reducing anxiety in unpredictable chronic mild stress conditions in rats. Behav Neurol. 2017;2017:5091027. PubMed.
  4. Seredenin SB, Semenova TP, Kozlovskaia MM, et al. The characteristics of the anxiolytic action of taftsin and its analog TP-7 on behavior and serotonin metabolism in the brain of rats with chronic deprivation of serotoninergic system activity [in Russian]. Eksp Klin Farmakol. 1995;58(6):3–6. PubMed.
  5. Vyunova TV, Andreeva L, Shevchenko K, Myasoedov N. Peptide-based anxiolytics: the molecular aspects of heptapeptide Selank biological activity. Protein Pept Lett. 2018;25(10):914–923. PubMed.
  6. Kost NV, Sokolov OIu, Gabaeva MV, et al. Semax and selank inhibit the enkephalin-degrading enzymes from human serum [in Russian]. Bioorg Khim. 2001;27(3):180–183. PubMed.
  7. Sokolov OY, Meshavkin VK, Kost NV, Zozulya AA. Effects of Selank on behavioral reactions and activities of plasma enkephalin-degrading enzymes in mice with different phenotypes of emotional and stress reactions. Bull Exp Biol Med. 2002;133(2):133–135. PubMed.
  8. Zolotarev IuA, Dadaian AK, Dolotov OV, et al. Evenly tritium-labeled peptides and their in vivo and in vitro biodegradation [in Russian]. Bioorg Khim. 2006;32(2):183–191. PubMed.
  9. Ashmarin IP, Baglikova KE, Edeeva SE, et al. A comparative analysis of distribution of glyprolines administered by various routes [in Russian]. Bioorg Khim. 2008;34(4):464–470. PubMed.
  10. Food and Drug Administration. Certain bulk drug substances for use in compounding that may present significant safety risks (category 2). Content current as of April 22, 2026. FDA.
  11. Doyno CR, White CM. Sedative-hypnotic agents that impact gamma-aminobutyric acid receptors: focus on flunitrazepam, gamma-hydroxybutyric acid, phenibut, and selank. J Clin Pharmacol. 2021;61(Suppl 2):S114–S128. PubMed.
  12. 21 CFR 1308.13, Schedule III. eCFR.
  13. World Anti-Doping Agency. The 2026 Prohibited List, in effect from January 1, 2026. WADA.
  14. Zozulia AA, Neznamov GG, Siuniakov TS, et al. Efficacy and possible mechanisms of action of a new peptide anxiolytic selank in the therapy of generalized anxiety disorders and neurasthenia [in Russian]. Zh Nevrol Psikhiatr Im S S Korsakova. 2008;108(4):38–48. PubMed.
  15. Medvedev VE, Tereshchenko ON, Israelian AIu, et al. A comparison of the anxiolytic effect and tolerability of selank and phenazepam in the treatment of anxiety disorders [in Russian]. Zh Nevrol Psikhiatr Im S S Korsakova. 2014;114(7):17–22. PubMed.
  16. Medvedev VE, Tereshchenko ON, Kost NV, et al. Optimization of the treatment of anxiety disorders with selank [in Russian]. Zh Nevrol Psikhiatr Im S S Korsakova. 2015;115(6):33–40. PubMed.
  17. Uchakina ON, Uchakin PN, Miasoedov NF, et al. Immunomodulatory effects of selank in patients with anxiety-asthenic disorders [in Russian]. Zh Nevrol Psikhiatr Im S S Korsakova. 2008;108(5):71–75. PubMed.
  18. Panikratova YR, Lebedeva IS, Sokolov OY, et al. Functional connectomic approach to studying Selank and Semax effects. Dokl Biol Sci. 2020;490(1):9–11. PubMed.
  19. Czabak-Garbacz R, Cygan B, Wolański L, Kozlovsky I. Influence of long-term treatment with tuftsin analogue TP-7 on the anxiety-phobic states and body weight. Pharmacol Rep. 2006;58(4):562–567. PubMed.
  20. Rahman OF, Lee SJ, Seeds WA. Therapeutic peptides in orthopaedics: applications, challenges, and future directions. J Am Acad Orthop Surg Glob Res Rev. 2026;10(1):e25.00236. PubMed.
  21. Vanhee C, Francotte A, Janvier S, Deconinck E. The occurrence of putative cognitive enhancing research peptides in seized pharmaceutical preparations: an incentive for controlling agencies to prepare for future encounters of the kind. Drug Test Anal. 2020;12(3):371–381. PubMed.