What Is Selank?
Selank (TKPRPGP) is a synthetic heptapeptide analog of tuftsin, an endogenous immunomodulatory tetrapeptide derived from the Fc region of immunoglobulin G. Selank was developed at the Institute of Molecular Genetics of the Russian Academy of Sciences and has been studied for over three decades, primarily in Russian research institutions.
Unlike many research peptides, Selank has been studied in actual human subjects in Russia, where it has been used as an anxiolytic agent in clinical settings. This relatively deep research base — compared to peptides with only animal model data — makes it of particular interest to researchers studying anxiety, stress response, and cognitive function.
Selank sold by Evo Peptides is for research use only and is not intended for human consumption. It is not FDA-approved in the United States.
Mechanisms of Action
GABAergic Modulation
Selank's primary anxiolytic mechanism involves the GABAergic system — the same neurotransmitter pathway targeted by benzodiazepines. However, Selank appears to modulate GABA-A receptor sensitivity rather than directly agonizing benzodiazepine binding sites, which researchers hypothesize may explain an absence of dependency effects observed in animal studies.
Enkephalin Stabilization
Selank inhibits enzymes responsible for the degradation of endogenous enkephalins (endorphin-related neuropeptides), effectively extending their duration of action. This mechanism contributes to anxiolytic and mood-related effects in rodent models.
BDNF Upregulation
Studies document Selank's ability to increase brain-derived neurotrophic factor (BDNF) expression — a protein critical for neuronal plasticity, learning, memory consolidation, and protection against stress-induced neuronal damage.
Immunomodulation
Consistent with its tuftsin origins, Selank shows immunomodulatory activity in preclinical models, including regulation of IL-6, interferon gamma, and other cytokines involved in both inflammation and adaptive immune response.
Research Specifications
| Property | Value |
|---|---|
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro (TKPRPGP) |
| Molecular weight | ~751.9 Da |
| Amino acids | 7 |
| Common form | Lyophilized powder or nasal spray formulation |
| Storage | Refrigerated 2–8°C, protect from light |
| FDA status 2026 | Removed from Category 2 · Not yet Category 1 |
Selank vs. Semax
Selank and Semax are frequently compared because they are both cognitive/neurological peptides with nasal spray formulation histories and both originate from Russian research. However, they have distinct mechanisms and research profiles:
| Property | Selank | Semax |
|---|---|---|
| Primary effect | Anxiolytic, anti-stress | Cognitive enhancement, neuroprotection |
| Structural origin | Tuftsin analog | ACTH(4–7) analog |
| Key mechanism | GABAergic modulation, enkephalin stabilization | BDNF/NGF upregulation, dopaminergic |
| Research depth | Moderate — primarily Russian literature | Deep — Russian clinical + international preclinical |
| PCAC July 2026? | No (removed from Cat 2, future review TBD) | Yes (Day 2, July 24) |
See the Semax Research Guide for a full profile of the companion peptide.
Regulatory Status 2026
Selank was removed from the FDA's Category 2 restricted list in April 2026. Unlike Semax, it is not on the July 23–24 PCAC agenda. A future PCAC review date has not been announced. It remains available from US research peptide vendors for research use only.