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Selank

Selank is a synthetic heptapeptide consisting of seven amino acids (Thr-Lys-Pro-Arg-Pro-Gly-Pro) derived from the naturally occurring immunoregulatory peptide tuftsin. Originally developed at the Institute of Molecular Genetics of the Russian Academy of Sciences in cooperation with the V.V. Zakusov Research Institute of Pharmacology, Selank represents a metabolically stable analog of the tuftsin tetrapeptide (Thr-Lys-Pro-Arg) found in human immunoglobulin G heavy chains.

This peptide has gained considerable attention in neuropsychopharmacology due to its demonstrated anxiolytic and nootropic effects in both preclinical and clinical studies, particularly in anxiety management, cognitive enhancement, and mood regulation. Selank exhibits remarkable stability compared to its endogenous counterpart and maintains bioactivity through modulation of GABAergic, dopaminergic, and serotonergic neurotransmitter systems, making it unique among therapeutic peptides.

Chemical structure diagram of the peptide Selank showing its amino acid sequence and bonding.

Overview

Selank demonstrates no sequence homology with other known anxiolytic compounds, contributing to its unique therapeutic profile. The peptide is metabolized rapidly in the liver and eliminated through renal excretion, with complete clearance from circulation within 10 minutes post-administration using sensitive detection methods.

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Chemical structure & Properties

  • Molecular Formula: C33H57N11O9
  • Molecular Weight: 751.86 g/mol
  • Sequence: Thr-Lys-Pro-Arg-Pro-Gly-Pro (TKPRPGP)
  • Half-life: Approximately 2-3 minutes in circulation (rapid hepatic metabolism)
  • Stability: Enhanced metabolic stability compared to tuftsin due to C-terminal extension

Mechanism of Action

Selank exerts its therapeutic effects through multiple interconnected molecular pathways:

GABAergic System Modulation

Selank acts as a positive allosteric modulator of GABA-A receptors, leading to:

  • Enhanced inhibitory neurotransmission in the central nervous system
  • Increased binding affinity of endogenous GABA to receptors
  • Anxiolytic effects similar to benzodiazepines without sedation or dependence
  • Modulation of GABA transporter expression and function

Monoamine Neurotransmitter Regulation

The peptide influences neurotransmitter systems through:

  • Upregulation of serotonin metabolism in the brainstem
  • Modulation of dopamine and norepinephrine concentrations
  • Enhancement of monoamine availability in key brain regions
  • Stabilization of neurotransmitter balance under stress conditions

Neuroprotective and Neurotropic Effects

Selank promotes neuronal health and plasticity by:

  • Rapid elevation of brain-derived neurotrophic factor (BDNF) expression in the hippocampus
  • Enhancement of synaptic plasticity and neuronal survival
  • Protection against stress-induced neuronal damage
  • Support of long-term potentiation mechanisms

Enkephalin System Protection

The peptide demonstrates protective effects on endogenous opioid systems through:

  • Inhibition of enkephalin-degrading enzymes in plasma
  • Prolongation of enkephalin half-life and bioactivity
  • Enhancement of endogenous stress-response mechanisms
  • Modulation of pain perception pathways

Areas Investigated in

the Research Literature

Anxiety and Mood Disorders

Generalized Anxiety Disorder (GAD): Clinical studies demonstrate Selank's efficacy in treating:

  • Primary anxiety symptoms with significant reduction in Hamilton Anxiety Rating Scale scores
  • Anxiety-related somatic symptoms and autonomic dysfunction
  • Social anxiety and performance-related stress
  • Panic disorder symptomatology

Mechanism: GABAergic modulation provides anxiolytic effects comparable to benzodiazepines without associated risks of tolerance, dependence, or cognitive impairment.

Anxiety and Stress-Related Presentations: Short Russian trials have examined:

  • Generalized anxiety disorder, studied in short Russian trials
  • Anxiety-asthenic presentations, studied in short Russian trials
  • No controlled trial evidence exists for depression, bipolar disorder, or seasonal affective disorder

Mechanism: Serotonergic system modulation and BDNF upregulation support neuroplasticity and emotional regulation.

Cognitive Enhancement Applications

Nootropic Effects: Preclinical and clinical evidence supports benefits in:

  • Attention and concentration enhancement
  • Learning capacity and information processing speed
  • Cognitive performance under stress conditions

Mechanism: BDNF upregulation, enhanced synaptic plasticity, and optimized neurotransmitter balance contribute to cognitive improvements.

Neuroprotection: Research demonstrates protective potential in:

  • Age-related cognitive decline (investigational/preclinical)
  • Post-stroke cognitive recovery (investigational/preclinical)
  • Traumatic brain injury rehabilitation (investigational/preclinical)
  • Neurodegenerative disease progression (investigational/preclinical)
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Current Clinical Evidence

Safety Profile and Considerations

Preclinical Safety Data

Animal studies across multiple species demonstrate:

  • No acute toxicity at therapeutic doses (100-300 μg/kg)
  • Absence of behavioral toxicity or cognitive impairment
  • No histologic evidence of organ toxicity
  • Minimal adverse effects across various administration routes

Clinical Safety Profile

Human studies report excellent tolerability with:

  • Absence of sedation, amnesia, or cognitive dulling
  • No evidence of physical dependence or withdrawal symptoms
  • Minimal drug interactions with standard medications
  • Low incidence of treatment discontinuation due to adverse effects

Potential Concerns

FDA Safety Warnings:

  • Risk of immunogenicity with certain routes of administration
  • Potential for immune system hypersensitivity reactions
  • Quality concerns with compounded formulations
  • Lack of standardized purity and potency requirements

Theoretical Risks:

  • Unknown long-term effects on GABAergic system function
  • Potential for receptor desensitization with chronic use
  • Drug interactions with CNS-active medications

Contraindications

Selank should be avoided in:

  • Pregnancy and breastfeeding (insufficient safety data)
  • Active malignancy or history of cancer (theoretical concern)
  • Severe neurological disorders or seizure history
  • Known hypersensitivity to peptides or excipients

Regulatory Status and Legal Considerations

Regulatory information current as of 28 August 2026. This is a summary, not legal or medical advice, and status can change.

FDA Status

  • Classification: Not approved for human therapeutic use
  • Category: Previously nominated to Category 2. Listed as Nominated but Withdrawn from Category 2 as of April 22, 2026. Not approved for therapeutic use in the US.
  • Compounding: Removal from Category 2 on 22 April 2026 does not by itself authorize compounding. Selank is not on the FDA's 503A bulk drug substances list.
  • Research Use: Available as research chemical only

International Status

  • Russia: Approved for treatment of generalized anxiety disorder
  • CIS Countries: Limited approval for anxiety disorders
  • European Union: Not approved for therapeutic use
  • Other Countries: Generally classified as research chemical

WADA Status

  • Classification: Not specifically listed on the Prohibited List (2025)
  • Athletic Use: Regulatory status may change; caution advised
  • Testing: Detection methods available for anti-doping purposes

Legal Availability

  • Commercial Status: Not legally available as prescription medication in most countries
  • Market Presence: Sold as research chemicals or investigational compounds
  • Quality Control: No regulatory oversight for purity or potency in research markets
  • Clinical Use: Limited to research settings and experimental protocols
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Conclusion

What the evidence supports

Selank is a synthetic analog of the tuftsin peptide studied for anxiolytic and nootropic effects, primarily in Russian clinical research and preclinical models. That literature has not been replicated in independent controlled trials, and there is no standardized dosing or long-term safety data outside those settings. Selank is not FDA approved in the United States and is not on the FDA's 503A bulk drug substances list, so no lawful compounding pathway currently exists. This page summarizes the published research and nothing further.

Selank Scientific

DATA SUMMARY

MOLECULAR CHARACTERISTICS
PRECLINICAL EFFICACY DATA
CLINICAL EVIDENCE SUMMARY
SAFETY PROFILE
REGULATORY STATUS
Parameter
Molecular Weight
Amino Acid Length
Half-Life
Bioavailability
Detection Window
Value
751.86 g/mol
7 residues (heptapeptide)
2-3 minutes (hepatic)
Enhanced via intranasal route
Up to several days (urine)
Application
Anxiolytic Effects
Cognitive Enhancement
Neuroprotection
Immunomodulation
Reported outcome (model)
Reduced anxiety behavior, enhanced GABA activity, no sedation
Improved memory consolidation, enhanced learning capacity
Increased BDNF, enhanced synaptic plasticity
No IGF-1 elevation, preserved glucose tolerance
Study Type
GAD Treatment Trial
Anxiety-Asthenic Study
Immunomodulatory Trial
Population
62 patients with GAD and neurasthenia
Multiple patient cohorts
Patients with anxiety disorders
Results
Equivalent efficacy to medazepam with superior tolerability
Significant anxiety reduction, improved quality of life
Normalized IL-6 levels, improved immune markers
Limitations
Russian study, limited international validation
Short-term studies (14-21 days)
Limited sample sizes, lack of placebo controls
Parameter
Acute Toxicity
Organ Toxicity
Adverse Events
Dependence Risk
Long-term Safety
Finding
No LD50 established (100-300 μg/kg tested)
No histologic changes in major organs
Minimal reported in clinical studies
No evidence of physical dependence or withdrawal
Limited human data available beyond 21 days
Authority
FDA
Russia
WADA
DEA
Classification
Non-Approved Substance
Approved Anxiolytic
Not Listed (2025)
Unscheduled
Status
Not approved for human use
Approved for GAD treatment
Not specifically prohibited in sports
Research use only

About this library

This library is published for education. It summarizes published research on compounds studied in this field. Many have no approved medical use, and several cannot lawfully be compounded in the United States. The presence of a page here does not mean Paragon offers that compound. Nothing on these pages is an offer to treat.

This page is general education about a compound studied in this field. Nothing here is medical advice, a recommendation, or an offer to prescribe or supply. A page appearing in this library does not mean Paragon Sports Medicine offers that compound.

Disclaimer: This information is provided for educational purposes only and does not constitute medical advice. Selank is not approved by the FDA for human therapeutic use. Patients should consult with qualified healthcare providers before considering any peptide therapy.

Statements on this page have not been evaluated by the FDA and are not intended to diagnose, treat, cure, or prevent any disease. Many peptides described here are not FDA approved for the uses discussed, and some cannot lawfully be compounded in the United States. Nothing on this page is medical advice or a recommendation for any individual. Whether any therapy is appropriate depends on your history, your laboratory results, and a clinical evaluation. Individual results vary. This page is published for education. Use of this site does not create a physician-patient relationship.

References

01
Functional Connectomic Approach to Studying Selank and Semax Effects. Dokl Biol Sci. 2020.
02
Selank, a Peptide Analog of Tuftsin, Attenuates Aversive Signs of Morphine Withdrawal in Rats. Bull Exp Biol Med. 2022.
03
Selank, Peptide Analogue of Tuftsin, Protects Against Ethanol-Induced Memory Impairment by Regulating of BDNF Content in the Hippocampus and Prefrontal Cortex in Rats. Bull Exp Biol Med. 2019.
04
The Influence of Selank on the Level of Cytokines Under the Conditions of Social Stress. Curr Rev Clin Exp Pharmacol. 2021.
05
The temporary dynamics of inflammation-related genes expression under tuftsin analog Selank action. Mol Immunol. 2014.