Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro (TKPRPGP). It was developed at the Institute of Molecular Genetics of the Russian Academy of Sciences, and it descends from tuftsin, a naturally occurring immune-signaling peptide. The first four residues are tuftsin itself; researchers tacked on a Pro-Gly-Pro tail to slow enzymatic breakdown and lengthen how long the molecule stays active. CAS number 129954-34-3; PubChem lists it as CID 11765600.
What it's proposed to do
Selank is studied as an anxiolytic, meaning an anti-anxiety agent. The most cited mechanism is positive allosteric modulation of GABA signaling. A 2018 review in Protein and Peptide Letters used radioligand binding work to argue that Selank acts as a positive allosteric modulator of GABA receptors, with concentration-dependent effects on GABA binding. The same review noted that when Selank was combined with diazepam, the effect was not simply additive and differed from either compound alone, which points to a binding profile that overlaps with but is not identical to a benzodiazepine.
That distinction matters because it is the basis for the recurring claim that Selank produces calming effects without the dependence and withdrawal associated with benzodiazepines. Because it is not a direct GABA-A agonist, the argument goes, it should not drive the same tolerance. This is plausible from the pharmacology but should be read as a hypothesis supported mostly by animal data, not a settled clinical fact.
The peptide also carries its tuftsin lineage into immune and neurochemical effects. Published work attributes to Selank changes in interleukin-6 and T-helper cytokine balance, shifts in monoamine and serotonin metabolism, and elevated brain-derived neurotrophic factor in rat hippocampus.
State of the evidence
Most of what exists is preclinical. In one representative study in Behavioral Neurology (2017), male Wistar rats under unpredictable chronic mild stress were tested in the elevated plus maze; the combination of Selank plus diazepam brought anxiety measures back toward pre-stress baseline, and the authors suggested it might allow lower benzodiazepine dosing.
Human data exists but comes with a caveat. Selank has been studied in Russian clinical settings for generalized anxiety disorder and neurasthenia, and it is registered and sold as a medicine in Russia. Much of that trial literature is published in Russian-language journals and has not been replicated in large, independently reviewed Western trials. So "clinically used in Russia" is true; "validated by the standards US or EU regulators expect" is not.
Regulatory and quality notes
Selank is not approved by the FDA and is not an approved drug in most Western countries. In the US it is sold only as a research chemical. Anything you find marketed online is research-use-only material, not a medicine, and not intended for human consumption. None of this is medical or dosing advice.
That status has a direct consequence for buyers: there is no regulatory body checking what is actually in the vial. With research-only peptides, identity and purity rest entirely on the seller's own testing. A current third-party certificate of analysis, ideally mass spectrometry to confirm the peptide is the correct sequence plus HPLC for purity, is the only real check that a product matches its label. The independent vendor ratings this site aggregates exist precisely because that verification is otherwise missing from this market.
Sources
- Selank, PubChem CID 11765600 (NIH/NLM)
- Vyunova et al., Peptide-based Anxiolytics: The Molecular Aspects of Heptapeptide Selank Biological Activity, Protein and Peptide Letters, 2018
- Peptide Selank Enhances the Effect of Diazepam in Reducing Anxiety in Unpredictable Chronic Mild Stress Conditions in Rats, Behavioral Neurology, 2017
- Selank overview (Wikipedia, for origin and regulatory status with primary citations)