Selank
Nootropics & Neuroprotection
CAS
129954-34-3
Molecular Weight
751
Da
Observational
A synthetic heptapeptide derived from Tuftsin, a naturally occurring tetrapeptide fragment of immunoglobulin G, extended at the C-terminus with the same Pro-Gly-Pro stabilizing tail found in Semax. Developed in the 1990s at the Institute of Molecular Genetics of the Russian Academy of Sciences by the same team responsible for Semax. Registered as a prescription medicine in Russia for anxiety disorders. Unlike Semax which is stimulating and nootropic, Selank is primarily anxiolytic and calming — the two are often described as complementary peptides. Demonstrates anxiolytic effects comparable to benzodiazepines in Russian clinical trials without the sedation, dependence risk, or cognitive impairment associated with that drug class. Research compound in all Western markets with no FDA or EMA approval.
Nasal · Injectable
Intranasal Suitable
Yes
Research Compound
Community Signal
Community signal positions Selank as the anxiolytic counterpart to Semax, where Semax is associated with stimulating cognitive effects, Selank is primarily discussed for anxiety reduction and mood stabilization. r/Nootropics contains meaningful Selank discussion alongside racetam and adaptogen threads. Onset is reported as rapid and the effects described as noticeably different from conventional anxiolytics, calmer without sedation is a common framing. Tolerance development is minimal according to most reports, which the community finds notable compared to benzodiazepines. The same sourcing and geographic concentration concerns as Semax apply. Some users report no effect, which may reflect sourcing variability.
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What It Is
Selank (sequence: Thr-Lys-Pro-Arg-Pro-Gly-Pro) was engineered by adding a Pro-Gly-Pro tail to Tuftsin, a tetrapeptide naturally produced by the spleen as a fragment of the IgG heavy chain. Tuftsin is biologically active but pharmacologically impractical, plasma peptidases cleave it within seconds. The Pro-Gly-Pro addition dramatically extends its stability and improves blood-brain barrier permeability, enabling intranasal delivery. The result is a compound with a triple pharmacological profile: anxiolytic activity comparable to classical benzodiazepines, nootropic cognitive support, and immunomodulatory effects inherited from its tuftsin parent. This combination, anxiety reduction without sedation or addiction, represents a meaningful clinical gap that Selank partially addresses, though the Western evidence base remains limited to Russian clinical data and small observational studies.
Mechanism of Action
Selank's mechanism involves multiple overlapping pathways that are not yet fully resolved. The primary anxiolytic mechanism appears to involve positive allosteric modulation of GABA-A receptors, similar in direction to benzodiazepines but acting at distinct binding sites and in a concentration-dependent manner, which may explain the absence of tolerance and dependence seen with classical benzodiazepines. Selank also inhibits enkephalinase enzymes that degrade endogenous enkephalins, increasing the half-life of leu-enkephalin in the bloodstream, a mechanism that contributes to both anxiolytic and mood-stabilizing effects. Additionally Selank upregulates BDNF expression, sharing this neurotrophin-promoting pathway with Semax. Immunomodulatory effects stem from its tuftsin heritage, tuftsin naturally activates macrophages and modulates cytokine expression, and Selank preserves these properties. Functional MRI studies in healthy humans showed Selank alters resting-state functional connectivity between the amygdala and temporal cortex, providing rare neuroimaging evidence of CNS activity in humans.
Use Cases
Selank's most validated application is generalized anxiety disorder, where a Russian clinical trial of 62 patients with GAD and neurasthenia showed anxiolytic effects comparable to medazepam, a classical benzodiazepine, but with additional antiasthenic and psychostimulant effects absent from the benzodiazepine. This is the strongest human clinical evidence for Selank and it comes from a single relatively small Russian trial that has not been replicated by independent Western research groups.
In the nootropic community Selank is used for anxiety reduction, stress resilience, improved focus under pressure, and mood stabilization, particularly valued for its absence of sedation which makes it compatible with cognitive work. It is often paired with Semax in stacks where the stimulating nootropic effect of Semax is balanced by Selank's calming anxiolytic activity.
Immunomodulatory applications are studied but less well characterized, Selank appears to reduce stress-induced cytokine dysregulation including IL-1β and IL-6 elevation in animal stress models.
All applications outside the Russian anxiety indication should be considered observational. No Western randomized controlled trials have been completed.
Known Risks
Selank has a favorable tolerability profile based on Russian clinical data and community observational experience. Crucially it does not appear to produce the sedation, cognitive impairment, physical dependence, or withdrawal effects associated with benzodiazepine anxiolytics, a significant safety advantage if confirmed in larger trials. Most commonly reported side effects are mild nasal irritation from intranasal administration and occasional mild fatigue. The GABA-A modulation mechanism raises theoretical questions about tolerance with chronic use that have not been adequately studied. Long-term safety data beyond clinical trial timeframes is absent. Quality control is a concern given research compound sourcing. As with Semax, the primary literature is largely Russian-language and difficult to independently evaluate.
Available Forms
Available primarily as intranasal drops, which is the preferred administration route given the nose-to-brain transport pathway that bypasses the blood-brain barrier. Subcutaneous injectable form is also available for research use. In Russia manufactured by Peptogen as registered nasal drops. Western supply is lyophilized powder requiring reconstitution. Research compound only outside Russia. Often sourced alongside Semax from the same suppliers given the overlapping research community interest.
Regulatory Status
Prescription medicine registered in Russia for anxiety disorders. Not approved by the FDA, EMA, or any other major Western regulatory authority. Not available through licensed compounding pharmacies in the US. Sold as a research compound in Western markets. Regulatory status varies internationally.
Sources
https://pubmed.ncbi.nlm.nih.gov/18454096/
https://pubmed.ncbi.nlm.nih.gov/28280289/
https://pubmed.ncbi.nlm.nih.gov/30255741/
https://pubmed.ncbi.nlm.nih.gov/32342318/
Similar Compounds
Semax, BPC-157, KPV, Carnosine
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