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Companion supplement

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Tripeptide antioxidant (companion supplement)

Glutathione

Also known as: GSH, L-Gamma-glutamyl-L-cysteinyl-glycine, Reduced glutathione, L-Glutathione

Endogenous tripeptide antioxidant. The cellular antioxidant mechanism is real, and the upstream precursor (N-acetylcysteine) is the standard antidote for paracetamol overdose. Aggressively marketed by IV clinics and the skin-lightening industry — most cosmetic and 'detox' claims run well past the evidence.

Reviewed 2026-05-05

What it does

Glutathione is the body's most abundant intracellular antioxidant — a short tripeptide of glutamate, cysteine, and glycine — central to liver detoxification pathways, redox balance, and the neutralization of reactive cellular byproducts. Its inclusion in this 'peptide companion' library follows the same logic as NAD+: it is technically a peptide (a tripeptide), is heavily marketed alongside peptide regimens, and most users encounter it through IV-clinic protocols rather than as a primary intervention. The strongest clinical evidence is indirect — N-acetylcysteine, the rate-limiting precursor for the body to make its own glutathione, is the standard antidote for paracetamol (acetaminophen) overdose. The IV-clinic marketing for skin lightening, brain-fog 'detox,' and general anti-aging runs well past the supporting evidence, particularly given persistent unresolved questions about IV and oral glutathione bioavailability and its rapid plasma clearance.

Used for

Dose

Starting
200,000 mcg · 1–3× per week (clinic IV)
Common
1,100,000 mcg · 1–3× per week (clinic IV)
Upper
2,000,000 mcg · 1–3× per week (clinic IV)
When
MorningAntioxidant load handles best in the morning with the day's redox demand ahead. IV-clinic protocols frequently pair with vitamin C in the same morning slot.
Site
intravenous (clinic infusion)

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⚠ Caution

  • Asthma (rare reports of bronchospasm with IV glutathione, particularly in sulfite-sensitive patients)
  • Active sulfite hypersensitivity
  • Pregnancy and breastfeeding (limited human safety data outside the NAC paracetamol-overdose context)
  • Cysteine metabolism disorders
  • Known hypersensitivity to glutathione or formulation excipients

Your stack

Track this peptide in your protocol — dose, schedule, vials on hand, refill projection. Stays in your browser; no account needed.

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Reconstitution & storage

Compounded sterile glutathione is supplied either as a prefilled vial of solution (200 mg/mL is common) or as lyophilized powder reconstituted with sterile preservative-free saline. Many compounding pharmacies use preservative-free saline rather than BAC water because the benzyl alcohol can be irritating with the volumes typical of glutathione dosing. Dose volumes for IV / SubQ doses are often multi-mL.

Storage. Compounded sterile solutions: refrigerate 2–8 °C, follow vendor expiration (typically 14–30 days once compounded). Lyophilized powder: refrigerate; reconstituted within 14 days. Liposomal oral: room temperature, dry, protected from light per label.

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Monitoring & questions

Reported side effects
  • IV: rare bronchospasm, flushing, nausea during rapid infusion
  • SubQ: injection-site stinging (sulfur compounds are irritating)
  • Oral: GI upset, sulfur-burp odor (the cysteine smell)
  • Inhaled / nebulized: bronchospasm has been reported and is a real concern in asthma
  • Headache
  • Skin rash (rare allergic reaction)
Biomarkers Juno tracks

Reference

How it works

Acts as the primary intracellular thiol antioxidant, donating its cysteine sulfhydryl to neutralize reactive oxygen species and to conjugate electrophiles (xenobiotics, toxic metabolites) for biliary or renal excretion via glutathione S-transferases. Cellular GSH:GSSG ratio is a key redox signal. Oral glutathione is largely degraded in the GI tract, with cysteine being the limiting precursor for de novo synthesis — a major reason that NAC (N-acetylcysteine), a stable cysteine precursor, is the clinical workhorse rather than oral GSH. IV glutathione bypasses GI degradation but plasma half-life is short (~minutes) and tissue uptake mechanisms are not fully characterized.

Juno's take

Glutathione is technically a tripeptide and sits in the library on the companion side. Two-tier story: the underlying biology is real, and the standard antidote for paracetamol overdose (N-acetylcysteine) works precisely because it lets your liver make more glutathione. The IV-clinic marketing for skin lightening, 'detox,' and general anti-aging runs much further out — limited trials, modest effects where measured, and persistent unresolved questions about how much of an IV or oral dose actually reaches the cells that need it.

EvidenceTier 2 — Human observational

Tiers are per indication. The same molecule can be Tier 1 for one use and Tier 4 for another — the tier reflects published literature, not community framing.

Paracetamol (acetaminophen) overdose (via NAC precursor mechanism)

Tier 1high confidence

N-acetylcysteine, the rate-limiting cysteine precursor for hepatic glutathione synthesis, is the standard-of-care antidote for paracetamol overdose. Prescribed by ED protocol; survival benefit demonstrated in multiple decades of clinical use. Indication is for NAC, not glutathione directly — but the mechanism is glutathione restoration in hepatocytes.

Skin lightening (cosmetic)

Tier 3medium confidence

Heavily marketed in Asian cosmetic markets (Philippines, Thailand, Indonesia). Some small RCTs (Sonthalia 2018 review) report modest skin-tone changes with oral glutathione; effect sizes are small and clinical relevance modest. Tier 3 for a cosmetic indication.

Liver disease / NAFLD / general 'detoxification'

Tier 3medium confidence

Mechanistic plausibility from the role of glutathione in phase II hepatic detoxification. Small RCTs in NAFLD report modest improvements in liver enzymes; clinical-outcome data is limited. The 'detox' marketing language is non-clinical.

No primary citations are anchored to this indication — the tier reflects the absence of usable literature, not a missing reference.

Parkinson's disease

Tier 3medium confidence

Pilot studies (Sechi 1996, Mischley 2017) of IV or intranasal glutathione in PD report some symptomatic improvements. Larger trials are limited. Tier 3 reflects underpowered studies with consistent but small signals.

No primary citations are anchored to this indication — the tier reflects the absence of usable literature, not a missing reference.

General anti-aging / longevity / 'master antioxidant' marketing

Tier 4high confidence

IV-clinic marketing positions glutathione as a general anti-aging intervention. There is no RCT supporting this in healthy adults. Mechanism-as-evidence reasoning amplified by clinic-economics incentive.

No primary citations are anchored to this indication — the tier reflects the absence of usable literature, not a missing reference.

Citations (2)
  1. [1]
    Efficacy of oral N-acetylcysteine in the treatment of acetaminophen overdose. Analysis of the national multicenter study (1976 to 1985)
    Smilkstein MJ, Knapp GL, Kulig KW, Rumack BH · New England Journal of Medicine · 1988 · PMID 3047581
    Foundational clinical evidence for NAC in paracetamol overdose — the indirect Tier 1 indication for glutathione restoration.
    View source
  2. [2]
    Glutathione as a skin whitening agent: facts, myths, evidence and controversies
    Sonthalia S, Jha AK, Lallas A, Jain G, Jakhar D · Indian Dermatology Online Journal · 2018 · PMID 29688177
    Cross-trial review of glutathione skin-lightening evidence — anchors Tier 3 for the cosmetic indication.
    View source