Selank
Selank is a synthetic heptapeptide developed in Russia, built from the immunomodulatory tetrapeptide tuftsin extended with a Pro-Gly-Pro tail. It is studied mainly for effects on anxiety-related behavior and immune signaling.
Overview
Selank is a short synthetic peptide created at the Institute of Molecular Genetics of the Russian Academy of Sciences. Its design starts from tuftsin, a naturally occurring tetrapeptide (Thr-Lys-Pro-Arg) that is cleaved from the Fc region of immunoglobulin G and has known effects on phagocytic cells. A Pro-Gly-Pro sequence was added to the C-terminus, a modification intended to slow enzymatic breakdown. The same stabilizing tail is used in the related Russian peptide semax.
Most published work on selank comes from Russian research groups and appears in Russian-language or regional journals. The literature covers rodent behavioral models, gene-expression studies and a limited number of clinical studies conducted in Russia. Independent replication outside that research network is sparse, and large randomized trials meeting current international standards have not been published. Selank is not approved by the FDA for any use and is treated in the West as a research compound.
Compare: Selank vs Semax.
Structure
Selank is a linear heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro (TKPRPGP). The first four residues are identical to tuftsin; the final three form the Pro-Gly-Pro extension that is expected to improve resistance to peptidases. It contains no cysteine, methionine or tryptophan, so it is not especially oxidation-prone. Research material is commonly supplied as an acetate or trifluoroacetate salt, and the counter-ion should be stated on the certificate of analysis.
Mechanism
The mechanism of selank is not firmly established. Published studies, largely from the developing institute, report that it modulates expression of genes involved in GABAergic neurotransmission and alters levels of several cytokines and monoamines in rodent tissue. Some work describes effects on enkephalin-degrading enzymes, which could indirectly raise endogenous enkephalin levels. Because the tuftsin core interacts with receptors on immune cells, immunomodulatory effects are also proposed. None of these pathways has been confirmed as the primary target by independent groups, so they should be read as hypotheses.
Research
Anxiety-related behavior in rodents
The largest body of selank research uses rodent behavioral tests such as the elevated plus maze and open field to examine anxiety-like behavior. Several studies from Russian groups report reduced anxiety-like measures in stressed or anxiety-prone animal strains. These are animal findings, often from a small number of laboratories, and methodological details vary between reports. They indicate a direction for research rather than an established pharmacological profile.
Gene expression and neurotransmitter studies
Transcriptomic studies in rodent brain tissue have reported changes in the expression of genes linked to GABA receptors, neurotransmitter transporters and inflammatory signaling after selank exposure. Other work has measured monoamine levels and enkephalinase activity. These studies help generate mechanistic hypotheses, but most were performed by the same research network, and the functional relevance of the expression changes has not been independently demonstrated.
Immune and antiviral signaling
Because selank is derived from tuftsin, some studies have examined its effects on cytokine expression and on markers of innate immune activity in cell and animal models. Reports describe shifts in interleukin and interferon-related signaling. The evidence is preclinical and limited in scope, and it does not establish any protective effect against infection in humans. Interpretation is also complicated by differences in cell types, exposure conditions and readouts between studies.
Clinical evidence
A small number of clinical studies have been conducted in Russia, generally in patients with anxiety-related diagnoses, and selank is reported to be registered as a medicine there. These studies are typically small, and many are not readily accessible in full text in English. Human evidence that meets current international trial standards remains limited, and no large multicenter randomized trial has been published.
Regulatory status
Selank is not approved by the FDA for any use, and it is not among the substances the FDA's Pharmacy Compounding Advisory Committee voted on in July 2026. It is reported to be registered as a medicine in Russia; regulatory status in other countries should be checked locally. In most Western markets it is handled as a research chemical. For sport, check the current WADA Prohibited List.
Status changes often. See the regulatory tracker for dated updates.
Quality and identity testing
A certificate of analysis for selank should show identity by mass spectrometry matching the expected mass shown on this page, along with HPLC purity and a representative chromatogram. Because the sequence contains three prolines, closely eluting deletion sequences (for example, missing one Pro) can be a concern, and the MS data should rule them out. The salt form and net peptide content should be reported, since acetate and TFA salts differ in peptide content per milligram. Water content and residual solvents are useful additional data.
Open Selank in the sequence analyzer to see the expected [M+H]+ and multiply charged ions for an MS identity check.
For a walkthrough of each section of a certificate, see how to read a COA.
Storage and stability
Store lyophilized selank sealed at -20 °C, protected from light and moisture, and allow vials to reach room temperature before opening to limit condensation. The sequence lacks cysteine, methionine and tryptophan, so oxidative degradation is less of a concern than for many peptides, but hydrolysis in solution still occurs over time. Prepared solutions should be aliquoted, kept cold and not subjected to repeated freeze-thaw cycles.
Download the Selank data sheet (PDF): sequence, masses, expected MS ions and handling on one printable page.
Latest research
The newest PubMed-indexed papers that mention Selank in their title or abstract, retrieved through Europe PMC and refreshed automatically. Inclusion is not an endorsement of a paper's findings.
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Frequently asked questions
Is selank FDA approved?
No. Selank is not approved by the FDA for any use, and it was not among the peptides reviewed by the FDA's Pharmacy Compounding Advisory Committee in July 2026. It is reported to be registered as a medicine in Russia, where it was developed. Outside Russia it is generally treated as a research compound, and its status in any given country should be checked with the local regulator.
What is the difference between selank and semax?
Both are Russian heptapeptides from the same institute, and both end in the stabilizing Pro-Gly-Pro tail. They differ in their core: selank is built on tuftsin (Thr-Lys-Pro-Arg), an immunoglobulin-derived peptide, while semax is built on the ACTH(4-7) fragment (Met-Glu-His-Phe). Selank research has focused on anxiety-related behavior and immune signaling, whereas semax research has focused on neurotrophic signaling and models of brain injury.
What is tuftsin?
Tuftsin is a naturally occurring tetrapeptide, Thr-Lys-Pro-Arg, released by enzymatic cleavage from the heavy chain of immunoglobulin G. It was described in the 1970s as a stimulator of phagocytic activity in macrophages and neutrophils. Selank uses the tuftsin sequence as its N-terminal core and adds a Pro-Gly-Pro extension that is intended to make the peptide more resistant to degradation.
Related compounds
- Semax
Semax is a synthetic heptapeptide developed in Russia as an analogue of the adrenocorticotropic hormone fragment ACTH(4-7), extended with a Pro-Gly-Pro tail. It is studied for neurotrophic signaling and in models of brain injury.
- DSIP
DSIP (delta sleep-inducing peptide) is a nonapeptide first isolated in the 1970s from the blood of rabbits in which sleep had been induced. Its physiological role and receptor remain unresolved, and human evidence is limited.
- Pinealon
Pinealon is a synthetic tripeptide (Glu-Asp-Arg) from Vladimir Khavinson's group in St. Petersburg, one of their short peptide bioregulators. It has been studied mainly in cell and animal models of neural aging and stress, with evidence mostly from that group.
References
- PubMed: all indexed literature on Selank
- ClinicalTrials.gov: registered studies mentioning Selank
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