Data edition of
Residue An evidence-graded reference for peptide science

Monograph in Regulatory peptides

Selank

A synthetic seven-residue peptide studied in Russia as an anxiolytic. The human evidence is a handful of small Russian clinical reports.

Also called TP-7 · Selank acetate · Thr-Lys-Pro-Arg-Pro-Gly-Pro

C

Best evidence: Limited / early human data

Small clinical studies in Russian journals, including a 62-patient comparison with medazepam; no large randomized placebo-controlled trial indexed in PubMed.

Not FDA-approved · FDA compounding nomination withdrawn

Residue Editorial Team · updated

What is Selank?

Selank is the synthetic heptapeptide Thr-Lys-Pro-Arg-Pro-Gly-Pro, studied mainly in Russia for anxiety1PubMedThe inhibitory effect of Selank on enkephalin-degrading enzymes as a possible mechanism of its anxiolytic activity. Zozulya AA et al. Bull Exp Biol Med. 2001.. In a study of 62 patients with generalized anxiety disorder or neurasthenia, its anxiolytic effect was similar to the benzodiazepine medazepam2PubMed[Efficacy and possible mechanisms of action of a new peptide anxiolytic selank in the therapy of generalized anxiety disorders and neurasthenia]. Zozulia AA et al. Zh Nevrol Psikhiatr Im S S Korsakova. 2008.. Laboratory work suggests it modulates GABA receptors and inhibits enzymes that break down enkephalins3PubMedPeptide-based Anxiolytics: The Molecular Aspects of Heptapeptide Selank Biological Activity. Vyunova TV et al. Protein Pept Lett. 2018.,1. It is not FDA-approved.

PubMed records
683 reviews
Trial publications
32 tagged RCT
Registered studies
20 active · 0 phase 3
Molecular weight
751.9g/mol · PubChem
Evidence grade
CLimited / early human data

Key findings

  1. In 62 patients with GAD or neurasthenia, selank (30) and medazepam (32) had similar anxiolytic effects; selank also showed anti-asthenic and psychostimulant effects2.
  2. Selank inhibited enzymatic breakdown of plasma enkephalin with an IC50 of 15 µM, more potently than bacitracin or puromycin1.
  3. It acted as a positive allosteric modulator of GABA binding in laboratory assays3.
  4. In rat frontal cortex, selank changed the expression of 45 of 84 neurotransmission genes at 1 hour, correlating with the effect of GABA4PubMedSelank Administration Affects the Expression of Some Genes Involved in GABAergic Neurotransmission. Volkova A et al. Front Pharmacol. 2016..
  5. FDA lists selank acetate among withdrawn compounding nominations and says it lacks important safety information for humans5FDACertain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks. U.S. FDA, content current as of 04/22/2026..

Written by Residue Editorial Team

Reviewed by Residue Editorial Team · source-by-source check,

First published

Last updated

Registry data · How we grade · Markdown + sources

What is Selank, chemically?

Identifiers retrieved from PubChem.
PubChem CID11765600 “Selank”
FormulaC33H57N11O9
Molecular weight751.9 g/mol
CAS (as listed)129954-34-3
FDA UNIITS9JR8EP1G
InChIKeyJTDTXGMXNXBGBZ-YVHUGQOKSA-N
Length7 residues
MechanismProposed: allosteric GABA-A modulation and enkephalinase inhibition
  • Polar
  • Basic (+)
  • Gly / Pro / Cys
Figure 1. Residue sequence of Selank (7 positions) as recorded in PubChem CID 11765600 — H-Thr-Lys-Pro-Arg-Pro-Gly-Pro-OH.

What is selank?

Selank is the heptapeptide Thr-Lys-Pro-Arg-Pro-Gly-Pro1. It ends in Pro-Gly-Pro, the same three residues that end semax (compare the sequence figures)6PubChemPubChem compound record: Selank. C33H57N11O9 · MW 751.9 g/mol.,7PubChemPubChem compound record: ACTH (4-7), Pro-Gly-Pro-. C37H51N9O10S · MW 813.9 g/mol.. Its PubMed record is small, and the clinical papers are published mostly in Russian journals8PubMedPubMed search: (selank[tiab]). 68 records at fetch..

How is Selank thought to work?

Two lines of laboratory work exist. In 2001, researchers reported that people with generalized anxiety disorder had a shortened enkephalin half-life and lower total enkephalinase activity, and that selank dose-dependently inhibited enzymatic hydrolysis of plasma enkephalin (IC50 15 µM)1. Later work showed selank acting as a positive allosteric modulator of GABA binding, interacting in a non-additive way with benzodiazepines3. In rats, selank and GABA produced correlated changes in the expression of neurotransmission genes in the frontal cortex4.

What have studies found?

Anxiety. The main clinical study compared selank (30 patients) with medazepam (32 patients) in generalized anxiety disorder and neurasthenia, using Hamilton, Zung and CGI scales. Anxiolytic effects were similar; selank also showed anti-asthenic and psychostimulant effects. Patients had low levels of a leu-enkephalin measure that rose with selank treatment2. The abstract does not report randomization or blinding.

Immune effects. In patients with anxiety-asthenic disorders treated for 14 days, selank shifted the Th1/Th2 cytokine balance; in vitro, it suppressed IL-6 gene expression in blood cells from patients with depression but not controls9PubMed[Immunomodulatory effects of selank in patients with anxiety-asthenic disorders]. Uchakina ON et al. Zh Nevrol Psikhiatr Im S S Korsakova. 2008..

Registered trials. A ClinicalTrials.gov search returns two records, both brain-stimulation device studies that do not test selank10TrialClinicalTrials.gov registry search: selank. 2 registered studies at fetch..

Is Selank FDA-approved?

Table 1. Regulatory status of Selank in the United States — from Drugs@FDA (openFDA) and FDA’s bulk-substance compounding categories, as fetched.
RecordStatusSource
FDA approval No approved application Drugs@FDA returned no application for “Selank”. openFDA
Compounding: nominated, then withdrawn
Selank acetate (TP-7)		 Withdrawn nomination FDA still lists its safety concerns:
“Compounded drugs containing selank acetate may pose risk for immunogenicity for certain routes of administration due to the potential for aggregation and peptide-related impurities. FDA lacks important information regarding any safety issues raised by selank acetate administered to humans.”		 5

FDA lists "Selank acetate (TP-7)" among substances whose compounding nominations were withdrawn. It notes possible immunogenicity from aggregation and peptide-related impurities, and states FDA lacks important information regarding any safety issues raised by selank acetate administered to humans5.

What is still unknown?

  • Placebo-controlled, blinded trials of adequate size, published with full methods.
  • Pharmacokinetics in humans are not described in the records we fetched.

What effects has Selank shown, by body system?

Each row is graded separately using the Residue evidence scale: a compound can carry an A for one use and a D for another.

Table 2. Research-observed effects of Selank by body system, with the strongest evidence available for each.
SystemWhat was observedGrade
AnxietyAnxiolytic effect similar to medazepam in a 62-patient clinical comparison2. C
Immune (cytokines)Changes in Th1/Th2 cytokine balance in patients treated for 14 days9. C
GABA system (lab/rat)Allosteric GABA-binding modulation; gene-expression changes in rat cortex3,4. D
Enkephalin degradationInhibited plasma enkephalinases in vitro (IC50 15 µM)1. D

How much research is there on Selank?

048 2001: 2 records 2001 2002: 3 records 2003: 2 records 2004: 2 records 2005: 4 records 2005 2006: 4 records 2007: 2 records 2008: 8 records 2009: 3 records 2010: 3 records 2010 2011: 3 records 2012: 2 records 2013: 3 records 2014: 5 records 2015: 1 records 2015 2016: 3 records 2017: 8 records 2018: 1 records 2019: 3 records 2020: 3 records 2020 2021: 2 records 2022: 1 records 2023: 0 records 2024: 0 records 2025: 0 records 2025 2026: 1 records (year to date) 2026
Figure 2. PubMed records per publication year matching (selank[tiab]) — 68 in total; peak 8 in 2008. The 2026 bar is year-to-date (hatched). Volume of literature is not evidence of efficacy. Run this query on PubMed.
Registered studies of Selank by phase and status
PhaseStudiesBreakdown
Not applicable 2
1 completed, 0 active or recruiting, 0 stopped, 1 other
Figure 3. 2 studies on ClinicalTrials.gov match the registry search selank. Multi-phase studies are counted at their highest phase.

Compare and continue

Questions readers ask

Is selank FDA-approved?

No. FDA lists 'Selank acetate (TP-7)' among withdrawn compounding nominations, citing immunogenicity risk and a lack of important safety information for humans5.

Does selank work for anxiety?

One 62-patient study found an anxiolytic effect similar to medazepam in generalized anxiety disorder and neurasthenia2. No large placebo-controlled trial is indexed in PubMed, so the evidence is limited.

How does selank work?

Laboratory studies suggest it allosterically modulates GABA receptors3 and inhibits enzymes that degrade enkephalins1.

What is the difference between selank and semax?

Selank is a heptapeptide studied for anxiety1; semax is an ACTH(4-7) analog extended with Pro-Gly-Pro, studied for stroke11. Both end in Pro-Gly-Pro and both are listed by FDA as withdrawn compounding nominations5.

References

Every source below was retrieved from its official API or page and cached on the data-edition date. Numbers match the margin notes.

  1. 1 PubMed Zozulya AA, Kost NV, Yu Sokolov O, et al. The inhibitory effect of Selank on enkephalin-degrading enzymes as a possible mechanism of its anxiolytic activity. Bull Exp Biol Med 2001. PMID 11550013; doi:10.1023/a:1017979514274.
  2. 2 PubMed 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]. Zh Nevrol Psikhiatr Im S S Korsakova 2008. PMID 18454096.
  3. 3 PubMed Vyunova TV, Andreeva L, Shevchenko K, et al. Peptide-based Anxiolytics: The Molecular Aspects of Heptapeptide Selank Biological Activity. Protein Pept Lett 2018. PMID 30255741; doi:10.2174/0929866525666180925144642.
  4. 4 PubMed Volkova A, Shadrina M, Kolomin T, et al. Selank Administration Affects the Expression of Some Genes Involved in GABAergic Neurotransmission. Front Pharmacol 2016. PMID 26924987; doi:10.3389/fphar.2016.00031.
  5. 5 FDA Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks. U.S. FDA, content current as of 04/22/2026.
  6. 6 PubChem PubChem compound record: Selank. C33H57N11O9 · MW 751.9 g/mol.
  7. 7 PubChem PubChem compound record: ACTH (4-7), Pro-Gly-Pro-. C37H51N9O10S · MW 813.9 g/mol.
  8. 8 PubMed PubMed search: (selank[tiab]). 68 records at fetch. PMID selank.
  9. 9 PubMed Uchakina ON, Uchakin PN, Miasoedov NF, et al. [Immunomodulatory effects of selank in patients with anxiety-asthenic disorders]. Zh Nevrol Psikhiatr Im S S Korsakova 2008. PMID 18577961.
  10. 10 ClinicalTrials.gov ClinicalTrials.gov registry search: selank. 2 registered studies at fetch.
  11. 11 PubMed Medvedeva EV, Dmitrieva VG, Limborska SA, et al. Semax, an analog of ACTH((4-7)), regulates expression of immune response genes during ischemic brain injury in rats. Mol Genet Genomics 2017. PMID 28255762; doi:10.1007/s00438-017-1297-1.