Selank
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Synthetic heptapeptide tuftsin analog with Pro-Gly-Pro C-terminal extension; anxiolytic GABA-A positive allosteric modulator with immunomodulatory and nootropic properties, without benzodiazepine-type dependence or sedation.
Quick Facts
| Property | Value |
|---|---|
| Also Known As | TP-7, Thr-Lys-Pro-Arg-Pro-Gly-Pro, Selanc |
| Category | Cognitive / Anxiolytic |
| Sequence | TKPRPGP (7 amino acids; tuftsin tetrapeptide TKPR + Pro-Gly-Pro) |
| Molecular Weight | ~751 Da |
| Molecular Formula | C33H57N11O9 |
| PubChem CID | 11765600 |
| Administration | Intranasal (primary), SubQ |
| Typical Dose Range | 250-500 mcg intranasal, 1-3x daily |
| Half-Life | ~30 minutes |
| Storage | Lyophilized: -20C, stable 1-2 years. Reconstituted/solution: 2-8C, use within 2-4 weeks. |
| FDA Status | Not FDA-approved. Approved in Russia for Generalized Anxiety Disorder (GAD). |
| WADA Status | Prohibited under S0 (Non-Approved Substances) |
Mechanism of Action
Selank is a synthetic analog of tuftsin (Thr-Lys-Pro-Arg), an endogenous immunomodulatory tetrapeptide derived from the Fc region of IgG, stabilized by the addition of a Pro-Gly-Pro (PGP) C-terminal extension that confers resistance to aminopeptidase degradation and extends its biological activity. This dual origin — tuftsin backbone plus PGP motif (shared with Semax) — gives Selank a unique pharmacological profile that bridges anxiolytic, nootropic, and immunomodulatory actions.
The primary anxiolytic mechanism of Selank operates through positive allosteric modulation of GABA-A receptors. Electrophysiological and gene expression studies demonstrate that Selank modulates GABAergic neurotransmission in a subtype-selective and concentration-dependent manner, potentiating inhibitory signaling without directly binding the benzodiazepine site. Notably, Selank blocks the modulatory activity of diazepam at GABA-A receptors, indicating it engages a distinct allosteric site (PMID-26924987, PMID-28293190). This mechanism accounts for its anxiolytic efficacy comparable to benzodiazepines but without dependence, tolerance, sedation, or withdrawal — a critical clinical differentiator (PMID-30255741).
Selank's immunomodulatory properties derive from its tuftsin origin. In a human clinical study of patients with GAD and concurrent neurasthenia, Selank treatment normalized aberrant cytokine profiles, significantly suppressing IL-6 levels and rebalancing Th1/Th2 immune responses, demonstrating that its anti-anxiety effects are accompanied by measurable immunological normalization (PMID-18577961). Animal studies confirm that Selank modulates cytokine expression under social stress conditions, further linking its anxiolytic and immunomodulatory actions (PMID-32621722).
Additionally, Selank regulates BDNF expression and modulates the opioidergic system, with studies demonstrating that its anxiolytic effects involve enkephalinase inhibition and interaction with endogenous opioid peptide pathways (PMID-22550852, PMID-15508574). Human fMRI data shows Selank alters functional connectivity patterns in brain regions associated with anxiety and cognitive processing, providing direct neuroimaging evidence for its central effects (PMID-32342318).
Key Research Areas
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GABA-A Allosteric Modulation โ Selank acts as a positive allosteric modulator of GABA-A receptors through a non-benzodiazepine binding site, producing anxiolysis without sedation, dependence, or tolerance. It blocks diazepam modulatory activity, indicating a distinct mechanism (PMID-26924987, PMID-28293190, PMID-30255741).
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Human Clinical Immunomodulation โ In GAD patients, Selank normalized cytokine profiles (IL-6 suppression, Th1/Th2 rebalancing), linking anxiolytic therapy to immune system normalization (PMID-18577961).
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Human Functional Neuroimaging โ fMRI studies demonstrate Selank-induced changes in functional connectivity in anxiety- and cognition-related brain networks in healthy volunteers (PMID-32342318).
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Ethanol-Induced Memory Protection โ Selank protects against ethanol-induced memory impairment in animal models, suggesting a role in neuroprotection during toxic exposure (PMID-31625062).
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Stress Cytokine Modulation โ Under social stress conditions, Selank modulates pro-inflammatory cytokine expression, providing a biological link between stress resilience and immune regulation (PMID-32621722).
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Opioid System Interaction and Anxiolysis โ Selank's anxiolytic properties involve the endogenous opioid system, including enkephalinase inhibition and novel interactions with opioid peptide pathways (PMID-22550852, PMID-15508574).
Evidence Level Summary
| Evidence Type | Count | Notes |
|---|---|---|
| Human RCTs | 0 | Russian Phase III GAD trials exist but are published in Russian-language journals |
| Human observational / clinical | 2 | Clinical immunomodulation study (PMID-18577961); fMRI functional connectivity (PMID-32342318) |
| Animal in vivo | 4 | GABA-A modulation, stress models, ethanol memory protection, morphine withdrawal |
| In vitro | 0 | โ |
| Systematic reviews | 0 | โ |
| Narrative reviews | 5 | Including molecular mechanism reviews, anxiolytic comparison, opioid system analysis |
Note on evidence: Selank is approved in Russia for Generalized Anxiety Disorder based on Phase III clinical trials. However, the pivotal trial data is largely published in Russian-language journals and is not fully accessible in English-language databases. The English-language evidence supports the mechanism and provides human-level data, but the formal clinical efficacy dataset remains underrepresented.
Clinical Applications
- Anxiety โ Primary indication; GABA-A allosteric modulation provides benzodiazepine-comparable anxiolysis without dependence
- Cognitive Enhancement โ BDNF upregulation and functional connectivity modulation support nootropic effects
- Neuroprotection โ Protection against neurotoxic insults (ethanol, stress-induced neuroinflammation)
- Immune Support โ Tuftsin-derived immunomodulation with IL-6 suppression and Th1/Th2 normalization
Protocols Using This Peptide
Ageless Peps Products
- AP-Selank-Vial โ Selank Vial, $37, intranasal/SubQ
Dosing Reference
Research Dosing Ranges (from literature)
| Route | Dose Range | Frequency | Duration | Source |
|---|---|---|---|---|
| Intranasal | 250-500 mcg | 1-3x daily | 3 weeks on / 1 week off | Russian clinical protocols |
| Intranasal | 100-250 mcg | 1-2x daily | First week (introductory) | Practitioner guides |
| SubQ | 150-300 mcg | 1x daily | 2-4 weeks | Practitioner guides |
Cycling
Standard cycling is 3 weeks on / 1 week off. No dependence, tolerance, or withdrawal has been reported in clinical use, and cycling is recommended primarily as a precautionary measure to maintain receptor sensitivity rather than due to observed tolerance.
Contraindications & Safety
- Contraindications: Concurrent benzodiazepine use (allosteric competition at GABA-A receptors; Selank blocks diazepam modulatory activity, potentially reducing benzodiazepine efficacy). Use caution with other GABAergic agents.
- Common side effects: Mild nasal irritation with intranasal use; transient fatigue during first 1-2 days of use (self-resolving).
- Drug interactions: Benzodiazepines (allosteric competition โ see PMID-26924987). Theoretical interaction with other GABAergic compounds (barbiturates, gabapentinoids). No formally documented interactions with SSRIs or SNRIs, though co-administration should be monitored.
- Pregnancy/nursing: Insufficient data; not recommended.
- Special populations: Russian clinical approval data suggests good tolerability with no abuse potential. No specific data on renal/hepatic impairment or pediatric populations in English literature.
Translation limitation: Russian Phase III clinical trial data supporting GAD approval is largely unavailable in English. Practitioners should note the approved clinical use abroad while recognizing the limitations of the English-language evidence base.
Cancer Considerations
CAUTION โ No direct safety data; tuftsin parent peptide is anti-tumor. No published studies evaluate Selank in patients with active tumors. However, the parent peptide tuftsin demonstrates predominantly anti-tumor activity: macrophage-mediated tumoricidal effects (PMID-3627109), competitive VEGF antagonism at neuropilin-1 (PMID-16371354), and enhanced anti-tumor immune responses in multiple cancer models. Selank does NOT promote angiogenesis (unlike BPC-157, TB-500, GHK-Cu). Its GABAergic and anti-inflammatory mechanisms are not directly pro-tumorigenic. However, the complete absence of cancer-specific Selank data means it cannot be declared safe in active malignancy. Avoid during active cancer; may be considered in remission with oncologist approval. See Compliance/Cancer Safety Matrix.
Synergistic Combinations
- Semax + Selank โ Complementary cognitive-anxiolytic "flow state" stack. Selank provides anxiolysis and emotional calm via GABA-A modulation; Semax provides cognitive drive via BDNF/dopamine enhancement. Both share the PGP stabilization motif and intranasal route. Human fMRI confirms distinct but complementary brain connectivity effects (PMID-32342318).
- BPC-157 + Selank โ Neuroprotection stack; BPC-157 provides broad tissue repair and neuroprotective signaling that complements Selank's GABAergic and immunomodulatory actions.
- P21 + NSI-189 + Selank โ Neurogenesis stack combining anxiolysis with hippocampal neurogenesis promotion.
Related Research
| PMID | Title | Year | Study Type |
|---|---|---|---|
| PMID-15508574 – A new property of the synthetic anxiolytic Selank and its de | A new property of the synthetic anxiolytic Selank and its derivatives | 2004 | Narrative review |
| PMID-18577961 – Selank Immunomodulatory Effects in Anxiety Patients | Selank Immunomodulatory Effects in Anxiety Patients | 2008 | Human clinical |
| PMID-22550852 – [The role of opioid system in peculiarities of anti-anxiety | The role of opioid system in peculiarities of anti-anxiety effect of peptide anxiolytic selank | 2012 | Animal in vivo |
| PMID-25176261 – [A comparison of the anxiolytic effect and tolerability of s | A comparison of the anxiolytic effect and tolerability of selank and phenazepam | 2014 | Narrative review |
| PMID-26924987 – Selank Affects GABAergic Neurotransmission Gene Expression | Selank Affects GABAergic Neurotransmission Gene Expression | 2016 | Animal in vivo |
| PMID-28293190 – GABA, Selank, and Olanzapine Affect the Expression of Genes | GABA, Selank, and Olanzapine Affect the Expression of Genes Involved in GABAergic Neurotransmission in IMR-32 Cells | 2017 | Animal in vivo |
| PMID-30255741 – Peptide-based Anxiolytics Selank Molecular Mechanisms | Peptide-based Anxiolytics: Selank Molecular Mechanisms | 2018 | Narrative review |
| PMID-31625062 – Selank Protects Against Ethanol-Induced Memory Impairment | Selank Protects Against Ethanol-Induced Memory Impairment | 2019 | Animal in vivo |
| PMID-32342318 – Functional Connectomic Approach to Semax and Selank Effects | Functional Connectomic Approach to Semax and Selank Effects | 2020 | Human neuroimaging |
| PMID-32621722 – Selank Cytokines Under Social Stress | Selank Cytokines Under Social Stress | 2020 | Narrative review |
| PMID-36322304 – Selank, a Peptide Analog of Tuftsin, Attenuates Aversive Sig | Selank, a Peptide Analog of Tuftsin, Attenuates Aversive Signs of Morphine Withdrawal in Rats | 2022 | Animal in vivo |
References
- PMID-15508574 โ Novel properties of Selank and derivatives
- PMID-18577961 โ Human clinical immunomodulation in anxiety
- PMID-22550852 โ Opioid system role in anxiolysis
- PMID-25176261 โ Selank vs phenazepam comparison
- PMID-26924987 โ GABAergic gene expression modulation
- PMID-28293190 โ GABA-A neurotransmission gene effects
- PMID-30255741 โ Peptide anxiolytic molecular mechanisms
- PMID-31625062 โ Ethanol memory impairment protection
- PMID-32342318 โ Human fMRI functional connectivity
- PMID-32621722 โ Stress cytokine modulation
- PMID-36322304 โ Morphine withdrawal attenuation
Related
#peptide #cognitive #intranasal #subq