Selank

Selank is a synthetic regulatory heptapeptide consisting of seven amino acids in the sequence threonine-lysine-proline-arginine-proline-glycine-proline (Thr-Lys-Pro-Arg-Pro-Gly-Pro). ^(1,2) The first four amino acids (Thr-Lys-Pro-Arg) constitute tuftsin, a naturally occurring tetrapeptide derived from the Fc region of the heavy chain of human immunoglobulin G (IgG). ⁽¹⁾ Tuftsin plays a role in the innate immune system, influencing phagocytic activity, cell motility, and immune cell function. The C-terminal Pro-Gly-Pro extension was added to improve metabolic stability and extend the peptide’s biological activity beyond the very short half-life of native tuftsin. ⁽²⁾

Selank was developed at the Institute of Molecular Genetics at the Russian Academy of Sciences in cooperation with the V.V. Zakusov Research Institute of Pharmacology. ^(1,2) The design goal was to create a stable anxiolytic peptide that could serve as an alternative to classical benzodiazepine drugs, retaining anxiolytic efficacy while avoiding the tolerance, physical dependence, withdrawal symptoms, sedation, and cognitive impairment that limit benzodiazepine therapy. ^(1,3) Published research has demonstrated that this goal was achieved: Selank produces anxiolytic effects comparable to benzodiazepines in clinical trials, with additional nootropic and antiasthenic properties that benzodiazepines do not possess. ⁽³⁾

The peptide has completed Stage III clinical trials in Russia for generalized anxiety disorder (GAD) and neurasthenia and holds approved prescription drug status. ⁽³⁾ Also designated TP-7 in some research literature, Selank is used clinically in Russia for anxiety disorders, neurasthenia, and as an immunomodulatory agent. ^(1,2) Like its companion neuropeptide Semax, the FDA has not approved Selank, the MHRA (UK), or the TGA (Australia) for any therapeutic indication outside Russia and the CIS countries. It is available as a research peptide for laboratory and investigational use in most Western markets.

Selank has poor oral bioavailability due to gastrointestinal peptidase degradation and is administered intranasally or subcutaneously in research settings. ⁽²⁾ The peptide crosses the blood-brain barrier via mechanisms facilitated by the Pro-Gly-Pro motif, which is thought to interact with transport systems or receptors enabling passage to central nervous system targets. ⁽⁵⁾

Healius supplies Selank as a lyophilized (also referred to as lyophilized in US research literature) powder in 10mg vials, intended strictly for laboratory and research applications.

Selank exerts its anxiolytic, nootropic, and immunomodulatory effects through multiple interconnected molecular pathways, with the GABAergic system representing the most extensively studied mechanism. ^(1,4)

The primary anxiolytic mechanism involves allosteric modulation of GABAA receptors. Clinical studies have demonstrated that Selank’s spectrum of physiological effects closely resembles that of classical benzodiazepines such as diazepam and phenazepam, suggesting a similar mechanistic basis. ⁽⁴⁾ Volkova et al.  ⁽²⁰¹⁶⁾, published in Frontiers in Pharmacology, analyzed the expression of 84 genes involved in neurotransmission in rat frontal cortex after Selank or GABA administration. ⁽⁴⁾ The study found a positive correlation between gene expression changes induced by Selank and those induced by GABA itself, confirming that Selank modulates the GABAergic system at the transcriptional level. Crucially, Selank was shown to compete for more than half of specific [3H] diazepam binding sites on rat brain cell membranes, providing direct evidence for interaction with benzodiazepine-binding sites on GABAA receptors. ⁽¹⁾

A 2017 study published in Frontiers in Pharmacology further investigated this mechanism by examining Selank, GABA, and the atypical antipsychotic olanzapine in neuroblastoma IMR-32 cells. ⁽⁶⁾ The results supported the hypothesis that Selank’s anxiolytic action involves regulation of GABAergic system activity through transcriptional modulation rather than direct receptor binding alone. A subsequent 2017 study demonstrated that combined administration of Selank and diazepam amplified their anxiolytic effects under chronic stress conditions, suggesting that Selank may increase the affinity of benzodiazepines for GABAA receptors. ⁽⁷⁾

Beyond GABAergic modulation, Selank influences multiple neurotransmitter systems. Research indicates effects on dopaminergic and serotonergic signaling, contributing to observed effects on motivation, cognitive drive, and mood regulation without causing overstimulation. ^(1,5) The peptide also inhibits enkephalinase enzymes responsible for degrading enkephalins, the body’s endogenous opioid peptides, thereby extending the duration of natural analgesic and anxiolytic molecules. ^(1,3)

Selank upregulates brain-derived neurotrophic factor (BDNF) expression in the hippocampus and prefrontal cortex, regions critical for memory processing and emotional regulation. ^(5,8) This neurotrophic effect provides a mechanistic basis for the cognitive-enhancing properties observed alongside the anxiolytic activity, and distinguishes Selank from benzodiazepines, which impair rather than enhance cognitive function.

The immunomodulatory dimension of Selank’s activity derives from its tuftsin heritage. Research has demonstrated that both the whole peptide and its individual fragments significantly alter the expression of genes encoding chemokines, cytokines, and their receptors, with effects on T helper cell balance and interleukin-6 (IL-6) signaling pathways. ^(1,5) This dual anxiolytic-immunomodulatory profile is unique among anxiolytic compounds and positions Selank at the intersection of neuroscience and immunology research.

Anxiety and stress-related conditions represent Selank’s primary research domain, supported by the most robust clinical evidence of any application. ⁽³⁾

The landmark clinical trial by Zozulia et al. ⁽²⁰⁰⁸⁾, published in Zhurnal Nevrologii i Psikhiatrii, evaluated Selank against medazepam (a classical benzodiazepine) in 62 patients with generalized anxiety disorder and neurasthenia. ⁽³⁾ Thirty patients received Selank and 32 received medazepam, with assessment using the Hamilton, Zung, and Clinical Global Impression (CGI) psychometric scales plus measurement of enkephalin activity in blood serum. ⁽³⁾ The anxiolytic effects of both drugs were similar, but Selank demonstrated additional antiasthenic and psychostimulant effects that medazepam did not produce. ⁽³⁾ The study also revealed that patients with GAD and neurasthenia had decreased leu-enkephalin half-life (tau 1/2), which correlated with disease duration and symptom severity. Treatment with Selank increased this parameter, particularly in patients with GAD, providing a biomarker-level explanation for the clinical improvement. ⁽³⁾

The absence of tolerance, dependence, and withdrawal effects has been consistently noted across Selank studies and represents one of the peptide’s most clinically significant advantages over benzodiazepines. ^(1,3) Classical benzodiazepines are effective anxiolytics but carry well-documented risks of physical dependence, withdrawal syndromes (including rebound anxiety, seizures, and insomnia), and cognitive impairment with chronic use. Selank’s anxiolytic profile without these liabilities addresses a critical unmet need in anxiety pharmacotherapy research.

For cognitive research, Selank has demonstrated memory-protective properties in experimental models. One investigation showed that Selank prevented ethanol-induced memory impairment, with the protective effect correlating with modulation of BDNF in relevant brain regions. ⁽⁸⁾ Studies have also indicated effects on attention, learning processes, and information processing speed, attributed to the peptide’s combined influence on BDNF expression, neurotransmitter balance, and GABAergic modulation. ^(1,5)

The immunomodulatory applications of Selank have been explored in antiviral research, with the minimal pharmacophore fragment Gly-Pro identified as having antiviral activity. ⁽¹⁾ Research has demonstrated significant changes in the expression of chemokine, cytokine, and receptor genes in mouse spleen following Selank administration, reflecting its tuftsin-derived immune-regulating properties. ⁽¹⁾

It is important to note that the clinical evidence base for Selank, while substantial in the Russian medical literature, is limited in English-language peer-reviewed journals. The Stage III clinical trials were conducted in accordance with Russian regulatory standards. Comprehensive Western-standard controlled clinical trials have not been published, which is one reason the peptide remains unapproved outside Russia and the CIS countries.

Selank and Semax are the two most frequently compared neuropeptides in both clinical and nootropic research contexts. Developed at the same institution (the Russian Academy of Sciences) and sharing the C-terminal Pro-Gly-Pro stability-enhancing motif, these peptides have complementary rather than overlapping mechanisms. ^(1,2)

Selank is derived from tuftsin (an immunomodulatory IgG fragment) and functions primarily as an anxiolytic through GABAergic allosteric modulation. Its research profile centers on reducing anxiety, improving stress resilience, stabilizing mood (also spelled stabilization), and modulating the immune system, with secondary cognitive benefits mediated by BDNF upregulation. ^(1,4) The overall character of Selank is calming, stabilizing, and balancing.

Semax is derived from the ACTH (4-7) fragment and functions primarily as a nootropic and neuroprotective agent by upregulating BDNF, activating dopaminergic and serotonergic systems, and modulating broad gene expression. ⁽⁹⁾ The research profile of Semax centers on cognitive enhancement, focus, memory, attention, and neuroprotection under stress or injury conditions. The overall character of Semax is more stimulating and activating.

The complementary nature of these mechanisms is why the Selank-Semax combination is among the most frequently discussed peptide stacking protocols in neuroscience research. Selank provides the anxiolytic/calming foundation through GABAergic modulation and immune support, while Semax provides the cognitive/stimulating dimension through dopaminergic activation and robust BDNF elevation. The 2017 study demonstrating that Selank enhances diazepam’s anxiolytic effects through allosteric modulation of GABAA receptors suggests that Selank may similarly complement the effects of other neuroactive compounds. ⁽⁷⁾

In terms of practical considerations, both peptides are administered intranasally, with similar onset times (15-30 minutes), are approved in Russia, and are available as research peptides elsewhere. For researchers interested in the complementary neuropeptide, Healius offers Semax as a separate product, enabling independent or combination protocol design.

1. Oathpeptides. Selank Research: Scientific Studies & Mechanisms Explained. Comprehensive review of Selank mechanisms, clinical evidence, and 2024-2025 research developments. December 2025.

2. Selank: From Tuftsin to Selank. BiotechPeptides review of tuftsin-derived heptapeptide structure, mechanism, and pharmacology. October 2025.

3. Zozulia AA, Neznamov GG, Siuniakov TS, et al. Efficacy and possible mechanisms of action of a new peptide anxiolytic, Selank, in the therapy of generalized anxiety disorders and neurasthenia. Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova. 2008;108(4):38-48. PMID: 18454096.

4. Volkova A, Shadrina M, Kolomin T, et al. Selank Administration Affects the Expression of Some Genes Involved in GABAergic Neurotransmission—Frontiers in Pharmacology. 2016; 7:31. PMC4757669.

5. Biotechpeptides. Structural and pharmacological analysis of Selank: Pro-Gly-Pro motif facilitating BBB transport, BDNF upregulation, monoamine neurotransmitter modulation, and immunomodulatory pathways. October 2025.

6. Volkova A, et al. GABA, Selank, and Olanzapine Affect the Expression of Genes Involved in GABAergic Neurotransmission in IMR-32 Cells. Frontiers in Pharmacology. 2017; 8:89.

7. Semenova TP, et al. Peptide Selank Enhances the Effect of Diazepam in Reducing Anxiety in Unpredictable Chronic Mild Stress Conditions in Rats. Bulletin of Experimental Biology and Medicine. 2017. PMC5322660.

8. Selank prevents ethanol-induced memory impairment correlating with BDNF modulation. Referenced in comprehensive Selank mechanism reviews and Medical Anti-Aging whitepaper, August 2024.

9. Semax: synthetic ACTH (4-7)-Pro-Gly-Pro heptapeptide with nootropic/neuroprotective profile through BDNF upregulation, dopaminergic/serotonergic activation. See Healius Semax product page for full research overview.

10. N-Acetyl Selank and N-Acetyl Selank Amidate: modified variants with enhanced enzymatic resistance through N-terminal acetylation and/or C-terminal amidation. Referenced in Peptides.org reviews and pharmacokinetic comparisons.

11. Kolomin TA, et al. Changes in gene expression of chemokines, cytokines, and their receptors in the mouse spleen after Selank administration. Referenced in immunomodulatory research reviews.

12. Seredenin SB, Kozlovskaia MM, et al. The anxiolytic action of an analog of the endogenous peptide tuftsin on inbred mice with different phenotypes of the emotional stress reaction. Zhurnal Vysshei Nervnoi Deiatelnosti. 1998; 48:153-160.

13. Paragon Sports Medicine. Selank Peptide comprehensive overview: GABAergic modulation, clinical applications, anxiolytic mechanism comparable to benzodiazepines without tolerance/dependence. 2025.

14. Medical Anti-Aging. Selank Medical Evidence whitepaper. Authors: Monis A, Maple K. August 2024. Review of clinical trial evidence, GABAergic gene expression, and anxiolytic efficacy.

This product is sold strictly for laboratory and research use only. It is not intended for human or animal consumption. It is not a dietary supplement, food, drug, or cosmetic. It is not intended to diagnose, treat, cure, or prevent any disease or condition. The buyer assumes all responsibility for the lawful use of this product in accordance with all applicable local, state, national, and international laws and regulations. By purchasing this product, the buyer confirms that they are a qualified researcher or are purchasing on behalf of a research institution.