Quick answer: Selank is a synthetic seven-amino-acid peptide built from the natural immunomodulatory tetrapeptide tuftsin, with a stabilizing tail added so it survives longer in solution. Most of the published research characterizes it in anxiety and GABA-system models, largely from Russian and Eastern European groups. It is approved as a prescription medication for certain neurological and anxiety-related indications in Russia and Ukraine, but in the United States and the EU it is not approved for any use, and Velora supplies it strictly as a research compound.
Research use only: what this article is, and what it isn’t
This article is a research-oriented reference for scientists evaluating Selank for in-vitro or preclinical work. It is not medical advice, and it is not a guide to human use.
Selank is not approved by the U.S. Food and Drug Administration, the European Medicines Agency, or any other Western regulator for any therapeutic indication. It is approved as a clinical pharmaceutical in Russia and Ukraine under regional regulators, including for generalized anxiety disorder, but that regional clinical product is a different thing from a research-grade peptide. The Selank that Velora Research supplies is a lyophilized research compound sold strictly for laboratory research use, not for human consumption, veterinary use, or any personal, nutritional, or cosmetic application.
Every effect described below is drawn from published preclinical or clinical literature and is framed as an observation in a research model, not a benefit to a person. Researchers are responsible for compliance with all applicable law, including the Federal Food, Drug, and Cosmetic Act (21 U.S.C. § 331, § 355, § 360bbb-3), and institutional review requirements.
What Selank actually is?
Start with the sequence, because it explains almost everything about the molecule. Selank is a heptapeptide (seven amino acids) with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. The first four residues, Thr-Lys-Pro-Arg, are tuftsin, a naturally occurring tetrapeptide first identified as an immune-modulating fragment of the antibody heavy chain. The last three residues, Pro-Gly-Pro, are a stabilizing extension bolted onto the C-terminus. That tail is not decorative. Short peptides get chewed up quickly by peptidases, and the Pro-Gly-Pro cap increases resistance to enzymatic degradation, which is the same stabilization trick used in the sister peptide Semax.
Selank was developed in the 1990s at the Institute of Molecular Genetics of the Russian Academy of Sciences. Its molecular weight is approximately 751.9 g/mol, with the molecular formula C33H57N11O9 and CAS number 129623-01-4. It ships as a white lyophilized powder.
Because the tuftsin fragment sits at the front of the molecule, Selank is often described as carrying two lineages at once: the immune-signaling heritage of tuftsin, and the regulatory-peptide behavior that the published research has characterized in the nervous system.
What has the research actually shown?
Here is where the discipline matters. The Selank literature is real, but it is concentrated in a specific set of research groups and model systems, and most of it is preclinical. The strongest and most mechanistically specific line of evidence sits in anxiety and GABA-system models.
The GABA-system mechanism. One of the most detailed molecular account comes from a 2018 review that examined how Selank produces its anti-anxiety activity in research models. The authors proposed that one of Selank’s mechanisms may involve subtype-selective, concentration-dependent allosteric modulation of GABA receptors, which is the same receptor system that classical benzodiazepines act on (Vyunova et al., *Protein and Peptide Letters*, 2018). “May involve” is the honest framing there; this is a proposed mechanism characterized in experimental systems, not a settled account.
Anxiolytic behavioral models. In a rat model of unpredictable chronic mild stress, Selank was studied alongside diazepam, and the authors reported that its anxiolytic effect was comparable to that of classical benzodiazepine drugs, with a mechanism they suggested may overlap (Kasian et al., *Behavioural Neurology*, 2017). This is an animal-behavior assay, and the comparison is between compounds in that model.
BDNF and neurotrophic signaling. In outbred rats, Selank was studied for its effect on ethanol-induced memory impairment and on brain-derived neurotrophic factor (BDNF) content in the hippocampus and prefrontal cortex (Kolik et al., *Bulletin of Experimental Biology and Medicine*, 2019). BDNF is a protein that supports the growth and maintenance of neurons, and it turns up repeatedly across both the Selank and Semax literature.
Human neuroimaging. One of the few human studies used resting-state functional MRI to examine how Selank and Semax affect whole-brain functional connectivity in 52 healthy participants, with the amygdala among the predefined regions of interest (Panikratova et al., *Doklady Biological Sciences*, 2020). This is worth knowing about because most of the Selank evidence base is animal work; direct human data is comparatively thin.
If you are designing a study, the takeaway is that the most consistently reported mechanistic finding is in the anxiolytic and GABA-system literature, the evidence concentrates around a specific group of Russian investigators, and the translation of these observations beyond those model systems is not fully characterized.
Selank at a glance
| Attribute | Detail |
|---|---|
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro (TKPRPGP) |
| Class | Synthetic heptapeptide, stabilized tuftsin analog |
| Molecular weight | ~751.9 g/mol (per Velora product specifications) |
| Molecular formula | C33H57N11O9 |
| CAS number | 129623-01-4 |
| Origin | Institute of Molecular Genetics, Russia, 1990s |
| Primary research areas | Anxiolytic models, GABA-system research, BDNF/neurotrophic research, immunomodulation |
| Regulatory status (Russia, Ukraine) | Approved prescription medication (Selank brand, intranasal) |
| Regulatory status (US, EU) | Not approved; research use only |
Reconstitution and concentration, in the units that matter
For a 10 mg vial, a common starting point used in laboratory practice is 2 mL of bacteriostatic water, which yields a 5 mg/mL stock. Using Velora’s product-page molecular weight of 751.9 g/mol, that 5 mg/mL stock corresponds to a molar concentration of approximately 6.65 mM. From there, cell-based assays that call for nanomolar-to-micromolar working concentrations will need serial dilution in an assay-appropriate buffer; a 6.65 mM stock diluted 1:1,000 lands at roughly 6.65 µM.
Reconstitute the way you would any lyophilized peptide: add diluent slowly against the inner glass wall, swirl gently rather than shaking, and label the vial with the date and the final concentration in both mg/mL and mM. Confirm the molecular weight on your specific batch Certificate of Analysis before you finalize the molar math, since that value drives every downstream dilution.
For storage, follow standard peptide-chemistry practice: keep the lyophilized vial sealed at -20°C, protected from light, and refrigerate any reconstituted stock at 2 to 8°C. Velora has not published a specific reconstituted stability window for this product, so treat the usable timeframe as something to establish from your own protocol and the batch COA rather than a fixed shelf life.
Routes used in published research
Two administration routes dominate the published Selank research in animal models: intranasal and subcutaneous. The intranasal route features heavily in the Russian research literature, which is also why “selank nasal spray” shows up so often as a search term. For research purposes, the route used in any protocol is a study-design choice to be selected and validated against the peer-reviewed literature and institutional approvals. None of these routes is a translation to human or veterinary use, and the Velora product is not sold for any such purpose.
Selank and Semax: the sister-peptide question
Researchers almost always encounter Selank and Semax together, and it helps to keep the difference straight. Both are seven-amino-acid regulatory peptides that came out of the same Russian research institute, both carry the C-terminal Pro-Gly-Pro stabilization, and both are approved clinical drugs in Russia while remaining research-only in the West. The difference is lineage and research focus. Selank descends from tuftsin and is most studied in the anxiolytic and GABA-system literature. Semax descends from an ACTH (4-10) derived analogue and is most studied in the BDNF, neurotrophic-factor, and cerebrovascular literature. For a full treatment of the second peptide, see our Semax research reference.
“When people ask me what to check first on a peptide like Selank, the answer is always the same: identity by mass spectrometry and purity by HPLC, on the specific batch. The sequence is short, and the chemistry is reproducible, but ‘reproducible’ only means anything if the COA confirms you actually have TKPRPGP at the purity the label claims. Everything downstream rests on that.”
Clark Jones, PhD, Velora Research
Working with verified material
Velora Research supplies Selank peptide as a 10 mg lyophilized research compound with a batch-specific third-party Certificate of Analysis. Each COA confirms identity by mass spectrometry and purity by HPLC at ≥99%, tied to the lot number on the vial. The same release protocol applies across the research peptide catalog, and the quality and testing process is documented end to end. For a research-grade regulatory peptide with a literature base as group-specific as Selank’s, knowing exactly what is in the vial is the difference between a reproducible result and an unexplained one.
Frequently asked questions
What are the documented Selank research findings?
Published preclinical and clinical literature has characterized Selank across several research areas: GABA-system signaling, anxiolytic behavioral models, BDNF and neurotrophic-factor expression, and immunomodulation derived from its tuftsin origin. These are areas of published research interest observed in experimental systems. They are not therapeutic claims, and they do not describe outcomes in people.
Is Selank FDA-approved?
No. Selank is not approved by the FDA or the EMA for any indication. It is approved as a prescription medication in Russia and Ukraine, but that regional product is distinct from a research-grade peptide, and Velora’s Selank is supplied strictly for laboratory research.
What is Selank’s molecular weight?
Approximately 751.9 g/mol, with the formula C33H57N11O9, per Velora’s product specifications. Confirm the value on your batch COA before calculating molar concentrations.
How does Selank differ from Semax?
Both are seven-amino-acid Russian-developed regulatory peptides sharing the Pro-Gly-Pro stabilization. Selank comes from tuftsin and is most studied in anxiolytic and GABA-system research; Semax comes from an ACTH (4-10) fragment and is most studied in BDNF and cerebrovascular research.
What is the sequence of Selank?
Thr-Lys-Pro-Arg-Pro-Gly-Pro (TKPRPGP). The first four residues are tuftsin; the last three are a stabilizing extension.
Sources and further reading
- Vyunova TV, Andreeva L, Shevchenko K, Myasoedov N. Peptide-based Anxiolytics: The Molecular Aspects of Heptapeptide Selank Biological Activity. Protein and Peptide Letters. 2018;25(10):914-923. PubMed
- Kasian A, Kolomin T, Andreeva L, et al. Peptide Selank Enhances the Effect of Diazepam in Reducing Anxiety in Unpredictable Chronic Mild Stress Conditions in Rats. Behavioural Neurology. 2017;2017:5091027. PubMed
- Kolik LG, Nadorova AV, Antipova TA, 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. Bulletin of Experimental Biology and Medicine. 2019;167(5):641-644. PubMed
- Panikratova YR, Lebedeva IS, Sokolov OY, et al. Functional Connectomic Approach to Studying Selank and Semax Effects. Doklady Biological Sciences. 2020;490(1):9-11. PubMed
This article is provided for laboratory and scientific reference. Selank is a research compound, not an approved drug in the United States or European Union. The research-grade material Velora Research supplies is distinct from the Selank-brand pharmaceutical approved by regulators in Russia and Ukraine. Products sold by Velora Research are for in-vitro research use only and are not intended for human or veterinary use. Researchers are responsible for compliance with applicable laws and institutional protocols.
