Gathering the record
Relay is organizing the evidence and source boundaries.
Endogenous thiol tripeptide / cellular redox buffer
A substance the body makes to help protect cells from chemical stress. People research it for skin and broader health claims.
Evidence is explained by question. Dosing references show their own check dates.
60-second overview
Why people look into it, what studies found, and what is still unknown.
Educational information only. Evidence reviewed through July 25, 2026. Published studies, sponsor announcements, and trials without results are labeled separately. Evidence gaps apply to the specific finding beside them.
Research questions
Each label shows how much evidence supports that question.
What studies show
Controlled oral trials show that direct glutathione can raise glutathione biomarkers; larger condition-specific trials show that target delivery does not necessarily improve clinical outcomes
Cells make glutathione from glutamate, cysteine, and glycine. Reduced glutathione (GSH) helps handle peroxides and electrophiles and can be oxidized to GSSG.
Those interventions may affect glutathione synthesis, but they are different molecules with different studies, exposures, and safety profiles.
A six-month controlled trial increased glutathione in several tissues, and a 2026 crossover pilot showed that formulation affected short-term blood exposure.
The 14-person 2026 pilot found higher blood exposure with one branded micellar product than a standard product at the tested doses.
Sputum measurements confirmed delivery, yet lung function, exacerbations, quality of life, and oxidative or inflammatory markers were not meaningfully improved.
The 24-week GROW study found no significant difference in growth, BMI, or measured inflammation compared with placebo.
A 21-person randomized pilot found no statistically significant difference in Parkinson rating-scale changes.
A 2025 systematic review found some melanin-index improvement in small oral and topical studies, but study quality was mixed and the single IV study was not convincingly positive.
FDA investigated acute reactions after IV glutathione and found excessive bacterial endotoxin in the bulk ingredient used to compound the injections.
There is no approved U.S. glutathione label that establishes a standard therapeutic indication, injectable formulation, route, dose, reconstitution method, or storage procedure.
Oral, inhaled, topical, and IV studies used different formulations for different research questions. Those protocols describe experiments; they are not interchangeable instructions.
These are common reasons people discuss glutathione, but the direct evidence reviewed here is biomarker-focused, mixed, condition-specific, or negative.
Risks & unknowns
Compounded injectable glutathione has a documented endotoxin and sterile-product risk.
Other human evidenceThis was a product-quality event. It should not be converted into an intrinsic side-effect rate for all glutathione products.
Open sourceCompounded injectable glutathione has a documented endotoxin and sterile-product risk.
Other human evidenceThis was a product-quality event. It should not be converted into an intrinsic side-effect rate for all glutathione products.
Open sourceThe available information does not reliably show how often particular side effects occur.
Evidence boundaryUnder-detected or under-reported events must not be described as rare.
Relay has not verified which side effects led people to stop treatment in studies.
Evidence boundaryThis is an evidence gap, not proof that discontinuations did not occur.
This profile does not contain verified, product-specific emergency instructions.
Evidence boundaryRelay does not infer emergency guidance from study discontinuations, mechanism, or incomplete adverse-event reporting.
Dosing references
Each table labels its source and applies only to the named route, product, or study. An online example or community report is not an approved dose.
Oral · Taken by mouth
Amounts reported in a human study. A studied amount is not automatically an approved dose or a recommendation for an individual.
A randomized trial studied 54 healthy nonsmoking adults.
| Stage / period | Amount in source | Frequency |
|---|---|---|
| 6 months | 250 or 1,000 mg groups | Daily |
The study assessed glutathione stores and related biomarkers. Oral supplementation does not establish an IV or subcutaneous dose, or a skin-lightening protocol.
Glutathione · six-month randomized oral trial Primary article · Methods / interventionThis reference checked Oct 20, 2026. The full-profile review date is shown at the top.This source does not establish a mixing volume or storage period for independently sourced powder. Use formulation-specific instructions; the study amount alone is not a reconstitution recipe.
Starting dose: the amount used at the beginning of the named label schedule or trial.
Maintenance: the ongoing amount described by that product label.
Trial target: the amount assigned to a study group. Different groups may stop increasing at different targets.
A randomized controlled study investigated whether oral reduced glutathione changed measured glutathione stores in healthy, non-smoking adults.
Population: 54 healthy, non-smoking adults
Design: Randomized, double-blind, placebo-controlled parallel-group biomarker trial
Mechanisms
Reduced glutathione (GSH) is a γ-glutamyl-cysteinyl-glycine tripeptide that participates in the GSH/GSSG redox couple, serves as an electron donor for glutathione peroxidases, and is conjugated to electrophiles by glutathione S-transferases. Human evidence establishes that direct oral supplementation can alter blood and tissue glutathione biomarkers and that oral formulation affects pharmacokinetics. Those findings do not establish broad clinical benefit. A 153-person inhaled cystic-fibrosis trial confirmed airway delivery without clinically relevant improvement, a later oral pediatric cystic-fibrosis trial was negative, and a 21-person IV Parkinson pilot did not find a significant efficacy difference. Skin-pigmentation studies show mixed modest signals with substantial route and study-quality limitations. FDA has documented endotoxin-related reactions involving compounded IV glutathione.
A plausible mechanism can explain why a study was attempted. It does not prove that the compound improves a human outcome.
Research reference
A reference for the studies, populations, and routes behind this profile.
Controlled oral, inhaled, intravenous, and topical studies examine biomarkers and disease-specific outcomes using very different formulations.
Research depth describes how large and mature the overall record is. It does not tell you whether the results were positive.
Oral target engagement is reproducible, but meaningful clinical effects are inconsistent, route-specific, and often unsupported by larger trials.
Confidence describes how reliable and consistent the conclusions are. It can be high for one outcome and low for another.
The strongest evidence type shows what the best-supported conclusions are actually based on.
Human findings are more directly relevant than animal or laboratory results, but they still apply only to the populations and outcomes studied.
Route-specific record
These are exposures used in cited research for a specific route and population—not an instruction for an individual.
Half-life describes how long it takes the measured amount in the body to fall by half. It is not a dosing recommendation.
Evidence can change by administration method. Findings from one route should not automatically be applied to another.
Evidence boundary: The endpoints were glutathione biomarkers, not symptoms, disease outcomes, recovery, cognition, or longevity. The oral study cannot establish the effects or safety of inhaled, topical, or intravenous formulations. Amounts shown describe cited research exposure—not a dosage recommendation.
Studies
Study arms are reported for transparency. They describe what researchers did in a defined record and do not transfer across identities, routes, formulations, or populations.
A later trial phase can ask a more mature question, but it does not guarantee a positive result, regulatory approval, or relevance outside the studied population.
Randomized, double-blind crossover pharmacokinetic pilot followed by a 30-day single-arm tolerability phase
14 healthy adults
The branded micellar formulation produced higher baseline-adjusted glutathione exposure and peak response than the standard preparation at the administered doses. Thirty-day clinical safety markers did not change significantly.
Study administration: Micellar glutathione 300 mg, liposomal glutathione 300 mg, and standard glutathione 500 mg in the crossover phase; micellar glutathione 600 mg/day in the follow-up
Limitations: Only 14 healthy adults participated, the follow-up was uncontrolled and short, branded formulations were studied, and the endpoints were pharmacokinetic and laboratory measures rather than clinical benefit.
Prospective, multicenter, randomized, double-blind, placebo-controlled oral trial
Young children with cystic fibrosis and pancreatic insufficiency; 58 completed the trial
Oral glutathione did not significantly improve growth, BMI, inflammatory markers, or the other secondary outcomes compared with placebo. It was generally well tolerated.
Study administration: Daily oral reduced glutathione or placebo in a disease-specific pediatric study
Limitations: This pediatric cystic-fibrosis trial does not answer general-wellness questions, but it shows that oral exposure and plausible antioxidant biology do not guarantee clinical benefit.
Randomized, double-blind, placebo-controlled parallel-group biomarker trial
54 healthy, non-smoking adults
Both oral glutathione groups increased measured glutathione in several body compartments. Larger and longer exposure generally produced larger changes, and levels returned toward baseline after washout.
Study administration: Oral reduced glutathione 250 mg/day, 1,000 mg/day, or placebo; these were study exposures, not general dosing guidance
Limitations: The trial established biomarker target engagement in healthy adults, not improvement in fatigue, liver disease, exercise recovery, cognition, longevity, skin outcomes, or another clinical condition.
Multicenter, randomized, double-blind, placebo-controlled inhalation trial
153 people with cystic fibrosis aged 8 years or older and baseline FEV1 of 40% to 90% predicted
Glutathione reached the airways, but it did not produce clinically relevant improvement in lung function, exacerbations, quality of life, or measured oxidative and inflammatory outcomes. Adverse-event incidence was similar to placebo.
Study administration: 646 mg inhaled glutathione in 4 mL or placebo every 12 hours through an investigational nebulizer
Limitations: The result applies to one inhaled regimen in cystic fibrosis. It does not answer oral, topical, or IV questions, and confirmed delivery does not prove clinical benefit.
Randomized, double-blind, placebo-controlled intravenous pilot
21 people with Parkinson's disease whose motor symptoms were not adequately controlled; 20 contributed post-randomization efficacy data
The pilot was tolerated, but differences in Parkinson rating-scale changes were not statistically significant during treatment or follow-up.
Study administration: 1,400 mg intravenous glutathione or placebo three times weekly; this was a disease-specific research protocol
Limitations: The sample was very small and designed for preliminary safety and signal detection. It cannot establish Parkinson efficacy, an optimal IV protocol, or benefit for healthy people.
Systematic review of oral, topical, and intravenous glutathione studies for skin lightening and melasma
Five randomized oral trials, one open oral study, topical studies, and one placebo-controlled intravenous study
Small oral and topical studies reported some melanin-index improvement, but effects were variable, not durable, and supported by a mixed-quality evidence base. The single IV study was not convincingly positive.
Study administration: Oral, topical, and intravenous glutathione across heterogeneous formulations and study designs
Limitations: Routes, products, populations, and outcome methods differed, and nearly as many studies had high as low risk of bias. The review does not establish injectable skin-lightening efficacy or safety.
Community
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Every structured report adds useful context about research setup, outcomes, and unwanted effects as the community dataset grows.
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2026-03-01 · PMID 41897500 · NCT06345950 · DOI 10.3390/antiox15030354
2025-06-01 · PMID 39444151 · DOI 10.1111/ijd.17535
2020-12-01 · PMID 32960827 · NCT03020719 · DOI 10.1097/MPG.0000000000002948
2019-06-07
2015-03-01 · PMID 24791752 · NCT01044277 · DOI 10.1007/s00394-014-0706-z
2013-07-01 · PMID 23631796 · NCT00506688 · DOI 10.1164/rccm.201303-0427OC
2009-05-15 · PMID 19230029 · DOI 10.1002/mds.22401