What is Selank?
Selank is a synthetic seven-amino-acid peptide, Thr-Lys-Pro-Arg-Pro-Gly-Pro, built from the immune peptide tuftsin with a Pro-Gly-Pro tail added for stability. It was designed in Russia and is studied mainly in rodent models of anxiety-like behavior and gene expression. Here is its structure, origin, research record and status.
Selank in one table.
| Sequence | TKPRPGP (Thr-Lys-Pro-Arg-Pro-Gly-Pro) |
|---|---|
| Length | 7 amino acids, a heptapeptide |
| Formula | C33H57N11O9 |
| Molecular weight | 751.9 g/mol (monoisotopic 751.4341) |
| PubChem CID | 11765600 |
| Parent peptide | Tuftsin, Thr-Lys-Pro-Arg |
| Status | Reported as an approved drug in Russia; not approved by the FDA |
Formula and masses from Helion's peptide molecular weight calculator, matching PubChem.
Tuftsin plus a stable tail.
Tuftsin is a four-amino-acid peptide, Thr-Lys-Pro-Arg, that comes from the heavy chain of immunoglobulin G. Selank is tuftsin with Pro-Gly-Pro added at the C-terminus to improve its metabolic stability. It was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences together with the V.V. Zakusov Research Institute of Pharmacology. In blood plasma it is broken down into smaller fragments, including TKPRP, TKP, RP and GP.
Mostly rodents.
Most published work on Selank is in rodents. Rat studies measured anxiety-like behavior on the elevated plus maze under chronic mild stress, both on its own and alongside diazepam. Gene expression studies found changes in 45 of 84 neurotransmission genes in rat cortex, including GABA-related genes, and in 34 of 84 inflammation-related genes in mouse spleen, and a mouse study measured changes in brain monoamines. The human data are small Russian clinical studies, such as a 2008 comparison with the anxiolytic medazepam in 62 patients.
Russia, not the FDA.
A 2026 review describes Selank as approved as a drug in Russia. It has no FDA approval, and outside Russia it is a research compound. Helion supplies compounds for laboratory research use only.
The sister peptide.
Selank shares its Pro-Gly-Pro design with Semax, a peptide built from a fragment of adrenocorticotropic hormone at the same institute. Selank vs Semax compares the two side by side.
Helion does not currently supply Selank.
Specs and storage by compound.
Questions (6)
What is Selank?
A synthetic seven-amino-acid peptide, Thr-Lys-Pro-Arg-Pro-Gly-Pro: the immune peptide tuftsin with a Pro-Gly-Pro tail added for stability.
What is the Selank sequence?
TKPRPGP: threonine, lysine, proline, arginine, proline, glycine, proline.
What is Selank made from?
Tuftsin (Thr-Lys-Pro-Arg), a fragment of the heavy chain of immunoglobulin G, extended with Pro-Gly-Pro.
What is the molecular weight of Selank?
751.9 g/mol (C33H57N11O9).
Is Selank approved?
It is described as an approved drug in Russia. It has no FDA approval.
Does Helion sell Selank?
Not currently.
Published studies (7)
- Selank Administration Affects the Expression of Some Genes Involved in GABAergic Neurotransmission
- Peptide Selank Enhances the Effect of Diazepam in Reducing Anxiety in Unpredictable Chronic Mild Stress Conditions in Rats
- Expression of inflammation-related genes in mouse spleen under tuftsin analog Selank
- [Effects of heptapeptide selank on the content of monoamines and their metabolites in the brain of BALB/C and C57Bl/6 mice: a comparative study]
- [Efficacy and possible mechanisms of action of a new peptide anxiolytic selank in the therapy of generalized anxiety disorders and neurasthenia]
- [Evenly tritium-labeled peptides and their in vivo and in vitro biodegradation]
- Therapeutic Peptides in Aesthetic, Metabolic and Endocrine Conditions: Effects, Safety, Clinical Applications, and Future Perspectives
Citations from PubMed for reference. They describe the compound in the literature, not any Helion lot, and nothing here is guidance on use.