Selank is a synthetic heptapeptide derived from the naturally occurring peptide, Tuftsin. Developed in Russia, it demonstrates anxiolytic, nootropic, and immunomodulatory effects, positioning it as a potential therapeutic for anxiety disorders and cognitive enhancement .
Structure and Mechanism
- Peptide Sequence: Thr–Lys–Pro–Arg–Pro–Gly–Pro
- Molecular Formula: C33H57N11O9
- Molecular Weight: 751.887 g/mol
Primary Actions
- GABAergic modulation: Acts on the GABAergic system with benzodiazepine-like anxiolysis but without sedation, dependence, or withdrawal .
- Gene expression effects: Influences genes tied to inflammation, immune function (IL-6, CX3CR1), and cognition .
- Design: Combines a short human IgG fragment with a Pro-Gly-Pro tripeptide tail to improve metabolic stability and half-life .
Key Benefits
- Anxiolytic Effects: Comparable to benzodiazepines, but without sedation or dependence .
- Cognitive Enhancement: Improves learning speed, memory retention, and memory trace stability .
- Immune Modulation: Regulates cytokines (IL-6) and shifts Th1/Th2 balance .
- Alcohol Withdrawal Support (preclinical): Reduces withdrawal behaviors in rodents .
- Cardiovascular Effects (preclinical): Lowers blood pressure and increases cerebral blood flow in animals.
- Additional: Shown in preclinical studies to aid stress reduction, weight control, and cholesterol reduction.
Discovery
- Tuftsin was identified (1970–1980) at Tufts University, regulating phagocyte function (phagocytosis, motility, immune activity) .
- Synthetic analogues were developed; Selank emerged at the Institute of Molecular Genetics, Russian Academy of Sciences, as a stabilized tuftsin analogue .
Research & Clinical Studies
Generalized Anxiety Disorder (GAD):
- In 62 patients (30 Selank, 32 medazepam), Selank matched benzodiazepine efficacy and showed extra psychostimulant benefits. Tau-leu-enkephalin levels dropped with Selank, linking to reduced GAD severity .
Anxiety & Phobia:
- In 60 patients, Selank demonstrated significant anxiolytic and nootropic effects vs. phenazepam, lasting >1 week post-dose .
Memory & Learning (preclinical):
- Rats in CAR training given Selank (300 μg/kg) had fewer errors and more correct responses, supporting cognitive benefits .
Immune Modulation (clinical):
- In GAD/neurasthenia patients, 14-day Selank therapy elevated IL-6 and shifted Th1/Th2 cytokine balance .
Alcohol Withdrawal (preclinical):
- In ethanol-dependent rats, Selank (0.3 mg/kg IP) reduced withdrawal symptoms within 48 hrs .
Cardiovascular Effects (preclinical):
- Cats given Selank (300 μg/kg IV) had –32% arterial BP and +24% cerebral blood flow; HR/respiration unaffected.
Weight & Lipids (preclinical):
- In high-fat-diet rats, intranasal Selank reduced cholesterol/fat by 25–58% and normalized metabolism vs. controls.
Suggested Use
- Nasal Spray: 1 spray per nostril daily; up to twice daily after week 2 (research protocols vary).
- Storage: Frozen until first use; refrigerate at 2–8°C for up to 60 days.
Side Effects & Safety
- Not benzodiazepine-like: No amnesia, dependence, or withdrawal symptoms .
- Possible peptide-class effects: Local irritation, dizziness, headache, nausea.
- Pharmacokinetics: Rapid elimination (~10 min in plasma). Distributed mainly in liver, kidneys, and heart.
Regulatory Status
- Approved: Russia, Ukraine (included in Russian Essential Medicines list).
- Not FDA-approved: In the U.S., available only for research purposes.
References
- Volkova A. et al. Selank Administration Affects the Expression of Some Genes Involved in GABAergic Neurotransmission. Front Pharmacol. 2016.
- Kasian A. et al. Peptide Selank Enhances the Effect of Diazepam in Reducing Anxiety in Stress Conditions in Rats. Behav Neurol. 2017.
- Zozulya AA. et al. The inhibitory effect of Selank on enkephalin-degrading enzymes. Bull Exp Biol Med. 2001.
- Sokolov OY. et al. Effects of Selank on behavioral reactions and enkephalin-degrading enzymes in mice. Bull Exp Biol Med.
- Uchakina ON. et al. Immunomodulatory effects of Selank in patients with anxiety-asthenic disorders. Zh Nevrol Psikhiatr Im S S Korsakova. 2008.
- Zozulia AA. et al. Efficacy and possible mechanisms of Selank in generalized anxiety disorder and neurasthenia. Zh Nevrol Psikhiatr Im S S Korsakova. 2008.
- Kolomin T. et al. Expression of inflammation-related genes in mouse spleen under tuftsin analog Selank. Regul Pept. 2011.
- Agapova TI. et al. Effect of semax on BDNF and NGF gene expression in rat hippocampus and cortex. Mol Genet Mikrobiol Virusol. 2008.
- Semenova TP. et al. Optimisation of learning and memory processes by Selank. Eksp Klin Farmakol. 2010.
- Kolomin TA. et al. Selank effects on anxiety and phobia. Zh Vyssh Nerv Deiat Im I P Pavlova. 2013.
- Semenova TP. et al. Effect of Selank on cognitive processes after catecholamine damage. Bull Exp Biol Med.
- Kost NV. et al. Semax and Selank inhibit enkephalin-degrading enzymes. Bioorg Khim. 2001.
- [Alcohol withdrawal rat model study — Selank reduced symptoms].
- [Cardiovascular study — IV Selank lowered BP, increased cerebral blood flow].
- [High-fat diet rat model — Selank reduced cholesterol, fat, and weight gain].
- [Pharmacokinetics: poor oral bioavailability, rapid elimination].
- [Intranasal vs intraperitoneal Selank — binding differences at NMDA/GABA receptors].
