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Glutathione (γ-Glutamylcysteinylglycine)
Also known as: GSH, L-Glutathione, Reduced Glutathione, γ-L-Glutamyl-L-cysteinyl-glycine
Confidence
Updated 2026-03-20
Glutathione is a naturally occurring tripeptide (Glu-Cys-Gly) and the body's most abundant intracellular antioxidant. It plays critical roles in detoxification, immune function, and oxidative stress defense. It is offered by virtually every peptide therapy clinic and IV therapy center, administered via IV infusion, subcutaneous injection, or oral/liposomal supplementation.
Class
Endogenous Tripeptide Antioxidant
Routes
Intravenous, Subcutaneous, Oral, Nebulized
Half-Life
IV: ~10–15 minutes (rapidly taken up by tissues); intracellular: hours
Glutathione serves as the primary intracellular thiol antioxidant, directly neutralizing reactive oxygen species (ROS), regenerating other antioxidants (vitamins C and E), conjugating toxins via glutathione S-transferase (Phase II detoxification), and maintaining protein thiol status. It cycles between reduced (GSH) and oxidized (GSSG) forms, with the GSH/GSSG ratio serving as a key indicator of cellular redox status.
Half-Life
IV: ~10–15 minutes (rapidly taken up by tissues); intracellular: hours
Bioavailability
IV: ~100% (direct systemic delivery) | Subcutaneous: moderate | Oral: ~3–5% (extensive first-pass metabolism); liposomal oral: ~15–25%
No FDA-approved drug indications. Widely used in clinical practice for: antioxidant support, detoxification support, skin brightening/hyperpigmentation, immune support, adjunct to chelation therapy, neurodegenerative disease support (Parkinson's), liver disease support, post-chemotherapy recovery.
Well-studied endogenous molecule with thousands of publications on its biochemistry. Clinical trial evidence for exogenous supplementation is moderate. Hauser et al. demonstrated IV glutathione improved symptoms in Parkinson's disease (short-term). Skin brightening effects documented in multiple studies via tyrosinase inhibition. Allen & Bradley (2011) showed IV glutathione reduced oxidative stress biomarkers. However, many clinical applications lack large RCTs.
Human Studies
50
Animal Studies
200
Generally very well tolerated. IV: rare anaphylactoid reactions, zinc depletion with chronic high-dose use, transient headache or flushing. SubQ: injection site reactions. Oral: GI discomfort at high doses. Theoretical concern: very high-dose IV glutathione may paradoxically act as a pro-oxidant. Long-term high-dose safety not well established.
Unclassified — endogenous molecule. Available as dietary supplement (oral/liposomal). Injectable forms prepared by compounding pharmacies under 503A/503B. One of the most commonly compounded injectable peptides/molecules in the US.
Drug Interactions: May reduce efficacy of certain chemotherapy agents that rely on oxidative mechanisms (use timing separation). May enhance effects of NAC (N-acetylcysteine) — both raise glutathione levels. Cisplatin interaction noted. Monitoring: Oxidative stress markers (8-OHdG, F2-isoprostanes), glutathione levels (whole blood GSH/GSSG ratio), liver function tests, zinc levels with chronic use. Research Gaps: Optimal IV dosing frequency for various conditions. Whether exogenous glutathione meaningfully raises intracellular levels long-term. Comparative efficacy of IV vs. liposomal oral vs. NAC precursor strategy.
Intravenous
Common Range
600–2000 mg per session
Timing
Infused over 15–30 minutes
Frequency
1–3 times per week (clinical protocols vary widely)
Cycling
Typically administered in courses of 8–12 sessions, then maintenance 1x/week or as needed
Important Note
Often combined with IV vitamin C and B-complex ("Myers Cocktail" variants). Most common route in clinic settings.
Subcutaneous
Common Range
200 mg per injection
Timing
Any time of day
Frequency
2–3 times per week
Cycling
Continuous or cyclical based on clinical goals
Important Note
Growing in popularity for at-home administration. May cause mild stinging at injection site.
Connect with a verified provider offering Glutathione therapy near you.
Metabolic Cofactor
NAD+ (nicotinamide adenine dinucleotide) is a critical coenzyme present in every living cell, essential for energy metabolism, DNA repair, sirtuin activation, and cellular signaling. While not a peptide, it is ubiquitously offered by peptide therapy clinics as a peptide-adjacent infusion or injection for anti-aging, cognitive enhancement, and addiction recovery. NAD+ levels decline with age, driving interest in exogenous supplementation.
Tissue Repair / Anti-Aging
GHK-Cu is a naturally occurring copper-binding tripeptide found in human plasma, saliva, and urine. Levels decline significantly with age (from ~200 ng/mL at age 20 to ~80 ng/mL at age 60). It has gained attention for its broad biological activities including wound healing, anti-inflammatory effects, collagen synthesis, and potential gene expression modulation.
Disclaimer: This content is for educational and informational purposes only and does not constitute medical advice. Always consult with a licensed healthcare provider before starting, stopping, or modifying any peptide therapy. PeptideSupplierMatch does not prescribe, sell, or distribute peptides.
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