Side-by-side · Research reference

GlutathionevsSelank

Side-by-side comparison across mechanism, dosage, evidence, side effects, administration, and stack synergies. Citations on every claim where available.

AHuman-MechanisticHUMAN-REVIEWED6/39 cited

BHuman-MechanisticAUTO-DRAFTED11/40 cited

Glutathione

Endogenous Tripeptide · Antioxidant

γ-Glu-Cys-GlyStructure

UbiquitousTissue distribution

GCL + GSBiosynthesisWang 2026 Aiana 2026

IV · Oral · Inhaled

Selank

Anxiolytic + Cognitive · Russian Pharma

150–300 mcg/doseIntranasalZaderej 2014

HumanMechanisticZaderej 2014 Medvedev 2007

~30 minOnset

Intranasal · 2–3×/day during stress / cognitive demand

01Mechanism of Action

Parameter

Glutathione

Selank

Primary target

Intracellular redox systems, glutathione peroxidase, glutathione transferase

Monoamine system (serotonin / GABA modulation) + immunomodulation via tuftsin domainZaderej 2014

Pathway

Synthesized via glutamate-cysteine ligase (GCL) → γ-glutamylcysteine → glutathione synthetase (GS) → GSH

Tuftsin-derived immune signaling + CNS monoamine modulation → reduced anxiety + improved mood / cognitionMedvedev 2007

Downstream effect

Reduction of reactive oxygen species, conjugation of electrophiles, maintenance of cellular thiol-disulfide balance, GPX4 activation for lipid peroxide reduction

Anxiolytic + cognitive enhancement; immunomodulation via increased IL-6 + IFN-γMedvedev 2007 Zaderej 2014

Feedback intact?

—

No GABA-receptor binding; no dependence reportedMedvedev 2007

Origin

Endogenous tripeptide; predominantly synthesized in liver, exported to extracellular space and tissuesTerrell 2025 Hecht 2026

Synthetic 7-AA peptide derived from human tuftsin (immune-system tetrapeptide)Zaderej 2014

Antibody development

—

02Dosage Protocols

Parameter

Glutathione

Selank

Endogenous synthesis

Hepatic synthesis ~10 g/day (basal rate)

Tissue-specific; demand-driven upregulation via Nrf2 signaling.

—

Exogenous oral

250–1000 mg/day

Bioavailability limited; gastric hydrolysis reduces systemic uptake.

—

IV supplementation

600–1200 mg (research protocols)

Used in clinical oxidative stress and hepatic detoxification studies.

—

Precursor strategy

N-acetylcysteine (NAC) 600–1200 mg/day

Provides cysteine for endogenous GSH synthesis; bypasses GI degradation.

—

Evidence basis

Animal mechanistic + human mechanistic

Human-mechanistic + Russian clinical trialsMedvedev 2007

Standard dose

—

150–300 mcg / dose intranasalZaderej 2014

Frequency

—

2–3× per day during stress

Lower / starter dose

—

75 mcg / dose

Duration

—

10–14 day cycles, repeated as needed

Reconstitution

—

Pre-formulated nasal spray (commercial); research vial: bacteriostatic water

Timing

—

Morning + early afternoon preferred

Half-life

—

Short (minutes plasma); CNS effect lasts ~3 hr

04Side Effects & Safety

Parameter

Glutathione

Selank

Oral supplementation

GI discomfort, bloating (mild, dose-dependent)

—

IV administration

Rare hypersensitivity, infusion site reaction

—

Inhalation

Bronchospasm risk in asthma (rare)

—

Tumor metabolism

Extracellular GSH catabolism supplies cysteine to tumors; theoretical concern in active malignancyHecht 2026

—

Nasal irritation

—

Mild burning or congestion (transient)

Sedation

—

None — distinct from benzodiazepinesMedvedev 2007

Dependence / withdrawal

—

None reported in clinical useZaderej 2014

Cognitive impairment

—

None — opposite effect (enhancement)

Allergic reaction

—

Rare hypersensitivity

Long-term safety

—

Limited Western RCT data

Pregnancy / OB

—

Avoid — insufficient data

Absolute Contraindications

Glutathione

—

Selank

·Pregnancy / breastfeeding
·Hypersensitivity to peptide

Relative Contraindications

Glutathione

·Active malignancy (theoretical cysteine supply risk)Hecht 2026
·Severe asthma (inhaled formulations)

Selank

·Active autoimmune disease (theoretical via immunomodulation)

05Administration Protocol

Parameter

Glutathione

Selank

1. Oral administration

Capsule or liquid form, 250–1000 mg once daily. Take on empty stomach for improved absorption, though GI hydrolysis limits bioavailability. NAC precursor strategy often preferred.

Pre-formulated nasal spray (commercial) or research vial reconstituted with bacteriostatic water.

2. Intravenous

Clinical protocols: 600–1200 mg slow infusion over 30–60 minutes. Used for acute oxidative stress, hepatic detoxification support. Administered in medical settings.

Intranasal — 1–3 sprays per nostril per dose. Tilt head slightly back.

3. Inhaled formulations

Nebulized GSH (research protocols). Monitor for bronchospasm in reactive airway patients. Used experimentally for pulmonary oxidative stress.

Morning + early afternoon for cognitive demand; PRN for acute anxiety.

4. Precursor supplementation

N-acetylcysteine (NAC) 600–1200 mg/day PO. Provides cysteine substrate for endogenous GSH synthesis. Bypasses gastric degradation, preferred for chronic supplementation.

Refrigerate after reconstitution; ≤30 days. Light-protected.

5. Caveat

—

Avoid co-administration with strong sedatives or other anxiolytics initially.