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Peptides · Cognitive
Selank
98.03% purity · Lot 6FN3TE · tested Apr 22, 2026CAS129954-34-3FormulaC33H57N11O9MW751.89
Tuftsin-analogue heptapeptide studied in anxiolytic research.
- Independently tested
- Lot-matched COA
- Lyophilized for stability
- Ships from the USA
Research use only. Not for human or veterinary use. Sold to qualified researchers aged 21+.
$75.002 for $75 — $37.50 per vial
1
Lot-matched documentation. Every order ships with the certificate for its lot. If a vial arrives damaged or doesn't match its paperwork, tell us within 72 hours and we'll replace it.
Latest lab results
Third-party testedSelank 10 mg
- Purity (HPLC-UV)
- 98.03%
- Identity (LC-MS)
- Confirmed — Selank
- Lot
- 6FN3TE
- Tested
- Apr 22, 2026
- Lab
- Freedom Diagnostics Testing
Your order ships with the certificate for its own lot.
About Selank
Tuftsin-analogue heptapeptide studied in anxiolytic research.
Supplied as
10 mg per vial, as a lyophilized powder in a sealed glass vial with a crimped cap. The lot number on the label matches the certificate of analysis in the COA library.
Storage and handling
Store lyophilized powder frozen (−20 °C) or refrigerated, sealed and away from light. Once reconstituted, keep refrigerated (2–8 °C).
Handle in a laboratory setting using appropriate protective equipment. Consult the certificate of analysis and safety data for lot-specific information.
Important research notice. This product is intended solely for in-vitro and laboratory research. It is not a drug, food, supplement or cosmetic, has not been evaluated by the FDA, and must not be used in humans or animals. Peptides Only does not provide usage or dosing information.
Research summary
Selank is a synthetic heptapeptide (Thr-Lys-Pro-Arg-Pro-Gly-Pro) that extends tuftsin, a natural immunomodulatory tetrapeptide, with a Pro-Gly-Pro tail. Developed by Russian researchers, it has been studied mainly in rodent models of stress and anxiety-like behavior and in laboratory work on GABA receptor binding, enkephalin-degrading enzymes and gene expression. Peptides Only supplies Selank as a lyophilized compound for laboratory research only.
- Also known as
- TP-7 · Thr-Lys-Pro-Arg-Pro-Gly-Pro · TKPRPGP · tuftsin analog
- Sequence
- Thr-Lys-Pro-Arg-Pro-Gly-Pro
What is Selank?
Selank is a seven-residue peptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro1. Its first four residues are tuftsin, a naturally occurring tetrapeptide studied for decades as an immunomodulator2, and Russian researchers describe Selank as a synthetic peptide built on the basis of tuftsin3.
The added Pro-Gly-Pro belongs to the glyprolines, a peptide family that the same research network reported to be unusually stable in the body. Selank and its sister peptide Semax were designed as hybrids that pair a biologically active fragment with this stabilizing tail4. In blood plasma, tritium-labeling studies identified Thr-Lys-Pro-Arg-Pro, Thr-Lys-Pro, Arg-Pro and Gly-Pro as Selank's main breakdown products5.
Mechanisms under study: GABA, enkephalins and gene expression
Selank's mechanism has been approached from several directions. In radioligand experiments on brain cell membranes, Selank changed the binding of tritium-labeled GABA in a pattern consistent with positive allosteric modulation of GABA receptors, and it altered the binding effects of diazepam and olanzapine1. In rat frontal cortex, Selank changed the expression of neurotransmission-related genes within hours, in a pattern that correlated with the changes produced by GABA itself6. A study in human IMR-32 neuroblastoma cells, by contrast, found no direct effect of Selank on those genes, although Selank blunted the gene changes that GABA produced7.
Earlier work focused on enkephalins. Selank inhibited enkephalin-degrading enzymes in human plasma in vitro more potently than the peptidase inhibitors bacitracin and puromycin. The same group reported a shorter enkephalin half-life in the blood of patients with generalized anxiety disorder and proposed enzyme inhibition as a possible basis for the anxiolytic-like activity reported for Selank8.
Immune and BDNF findings in rodents
Given its tuftsin origin, Selank has also been studied for immune effects. In mouse spleen, a single administration changed mRNA levels of complement C3, caspase-1, Il2rg and Xcr1 within 30 to 90 minutes, and its dipeptide fragment Gly-Pro produced largely similar profiles9.
In a model of long-term alcohol exposure, rats received ethanol as their only fluid for 30 weeks. Selank prevented the ethanol-associated rise in BDNF content in the hippocampus and frontal cortex, and the memory and attention deficits seen in an object recognition test during withdrawal3.
Human studies
Clinical research on Selank is limited to small Russian studies. One compared Selank with the benzodiazepine medazepam in 62 patients diagnosed with generalized anxiety disorder or neurasthenia, using the Hamilton, Zung and CGI rating scales and measuring serum enkephalin-degrading activity; the authors reported effects similar to the comparator10. Another compared Selank with phenazepam in 60 patients with anxiety and somatoform disorders11. Both used active comparators rather than placebo, and both were published in a Russian-language journal.
Limitations of the evidence
Almost all Selank research comes from a few Moscow institutions, notably the Institute of Molecular Genetics and the Zakusov Institute of Pharmacology, and independent replication is scarce9,3. A 2021 review by US pharmacists described Selank as a poorly studied Russian drug with GABAergic mechanisms that was being sold to US consumers as a dietary supplement12.
- Behavioral findings come mainly from rodent stress and anxiety-like behavior models.
- Mechanistic work points in several directions (GABA modulation, enkephalinase inhibition, immune gene expression) without an identified receptor.
- The human studies are small, used active comparators and were not placebo-controlled.
- Selank is not approved by the FDA or the European Medicines Agency, and it is not a dietary supplement.
Sourcing Selank for research
Every Peptides Only lot of Selank is independently tested and ships from the USA with a lot-matched certificate of analysis showing HPLC purity and mass-spec identity, published in our certificate library. It is also available with Semax and Pinealon in the Semax / Selank / Pinealon Set.
Selank FAQ
Is Selank approved by the FDA?
No. Selank is not FDA-approved and has not been authorized by the European Medicines Agency. Its clinical record consists of small Russian studies10,11, and US reviewers have criticized its sale to consumers as a supplement12. Peptides Only sells it only as a research compound.
Is Selank the same as tuftsin?
No. Tuftsin is the natural tetrapeptide Thr-Lys-Pro-Arg. Selank keeps that sequence and adds Pro-Gly-Pro, which its developers intended to make the peptide more stable1,4.
What is the difference between Selank and Semax?
Both are Russian heptapeptides ending in Pro-Gly-Pro. Selank is built on tuftsin and is studied mainly for GABAergic modulation, enkephalin metabolism and stress behavior; Semax is built on the ACTH(4-7) fragment and is studied mainly for BDNF expression and ischemia models4. Our Semax vs Selank article compares them in detail.
Does Selank act on GABA receptors?
Radioligand binding work suggests allosteric modulation of GABA receptors1, and gene-expression studies in rats point the same way6, but a study in human neuroblastoma cells found no direct effect on GABAergic genes7. The mechanism is not settled.
How is lyophilized Selank stored?
Like most lyophilized peptides, sealed vials are generally kept cold, dry and protected from light. See our guide to peptide storage and stability.
Further reading
References
- Vyunova TV, Andreeva L, et al. Peptide-based Anxiolytics: The Molecular Aspects of Heptapeptide Selank Biological Activity. Protein Pept Lett. 2018;25(10):914-923. PubMed 30255741
- Siebert A, Gensicka-Kowalewska M, et al. Tuftsin - Properties and Analogs. Curr Med Chem. 2017;24(34):3711-3727. PubMed 28745220
- Kolik LG, Nadorova AV, et al. Selank, Peptide Analogue of Tuftsin, Protects Against Ethanol-Induced Memory Impairment by Regulating of BDNF Content in the Hippocampus and Prefrontal Cortex in Rats. Bull Exp Biol Med. 2019;167(5):641-644. PubMed 31625062
- Ashmarin IP, Samonina GE, et al. Natural and hybrid (chimeric) stable regulatory glyproline peptides. Pathophysiology. 2005;11(4):179-185. PubMed 15837162
- Zolotarev IuA, Dadaian AK, et al. Evenly tritium-labeled peptides and their in vivo and in vitro biodegradation. Bioorg Khim. 2006;32(2):183-91. PubMed 16637290
- Volkova A, Shadrina M, et al. Selank Administration Affects the Expression of Some Genes Involved in GABAergic Neurotransmission. Front Pharmacol. 2016;7:31. PubMed 26924987
- Filatova E, Kasian A, et al. GABA, Selank, and Olanzapine Affect the Expression of Genes Involved in GABAergic Neurotransmission in IMR-32 Cells. Front Pharmacol. 2017;8:89. PubMed 28293190
- Zozulya AA, Kost NV, et al. The inhibitory effect of Selank on enkephalin-degrading enzymes as a possible mechanism of its anxiolytic activity. Bull Exp Biol Med. 2001;131(4):315-7. PubMed 11550013
- Kolomin T, Morozova M, et al. The temporary dynamics of inflammation-related genes expression under tuftsin analog Selank action. Mol Immunol. 2014;58(1):50-5. PubMed 24291245
- Zozulia AA, Neznamov GG, 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;108(4):38-48. PubMed 18454096
- Medvedev VE, Tereshchenko ON, et al. A comparison of the anxiolytic effect and tolerability of selank and phenazepam in the treatment of anxiety disorders. Zh Nevrol Psikhiatr Im S S Korsakova. 2014;114(7):17-22. PubMed 25176261
- 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 34396551
Research summary reviewed 2026-10-26 against the cited literature.
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