Glutathione
Published research and evidence base
Glutathione (GSH) is an endogenous tripeptide (glutamate-cysteine-glycine) that functions as the principal intracellular thiol antioxidant and redox buffer. Human research falls into three broad strands: pharmacokinetic work comparing standard oral, liposomal/micellar and intravenous delivery; dermatological trials of oral, topical and intravenous glutathione for skin pigmentation; and precursor-based repletion strategies, most prominently glycine plus N-acetylcysteine (GlyNAC), studied in ageing, HIV and metabolic disease. Trial sizes are generally small, outcome measures are heterogeneous, and results in neurodegeneration have been largely negative for direct glutathione administration while precursor approaches have shown more consistent biochemical effects.
- Studies cited
- 15
- Published 2023+
- 9
- Newest paper
- 2026
- Last reviewed
- Aug 2026
Recurring themes in the literature
- Oral bioavailability of glutathione is contested; formulation (liposomal, micellar, orally dissolving film) substantially changes systemic exposure
- Repeated oral dosing raises whole-blood, erythrocyte and lymphocyte glutathione pools in healthy adults, with return to baseline after washout
- Skin-lightening trials report reductions in melanin index with oral and topical glutathione, but short durations and high risk of bias
- Intravenous glutathione for cosmetic or longevity indications lacks controlled efficacy data and carries documented safety concerns
- Direct glutathione administration in Parkinson's disease has not outperformed placebo; precursor supply via N-acetylcysteine shows more signal
- GlyNAC (glycine + N-acetylcysteine) corrects glutathione deficiency and oxidative stress markers in older adults and in people with HIV
- Oral glutathione lowered aminotransferases in an uncontrolled NAFLD pilot; no randomised confirmation
Compound identifiers
- CAS
- 70-18-8
- PubChem
- 124886
What Glutathione is, chemically.
- Molecular formula
- C10H17N3O6S
- Molecular weight
- 307.33 g/mol
- CAS number
- 70-18-8
- PubChem CID
- 124886
L-Glutathione
These figures come from the PubChem record for this compound and describe the free base. Lyophilised peptide is normally supplied as an acetate or trifluoroacetate salt and carries residual water, so the mass of powder in a vial is not the same quantity as the molecular weight above would suggest. Chromatographic purity on a certificate of analysis does not resolve that difference either — how to read a certificate of analysis explains why.
15 published studies.
Ordered by strength of study design, then by recency. Every entry links to its source record so the finding can be checked against the paper rather than taken on our word.
- 01Systematic review2026
The role of N-acetylcysteine and glutathione in the management of Parkinson's disease: a systematic review of oxidative biomarkers and clinical outcomes
Mohammed I, Nankya Y, Hong UT, et al. · Amino Acids · systematic review of 9 studies (2009-2019) totalling 196 participants with Parkinson's disease, comparing NAC or glutathione against placebo or healthy controls
N-acetylcysteine improved motor and non-motor symptoms and increased GSH/GSSG ratios, cerebrospinal fluid GSH and dopamine transporter binding, whereas intranasal glutathione produced only modest increases in brain glutathione without significant symptomatic or oxidative-stress benefit. The reviewers judged evidence for glutathione itself inconclusive.
- 02Systematic review2025
Glutathione as a skin-lightening agent and in melasma: a systematic review
Sarkar R, Yadav V, Yadav T, et al. · International Journal of Dermatology · systematic review of 10 years of PubMed, Embase and Cochrane records on topical, oral and intravenous glutathione for skin lightening and melasma
Five randomised controlled trials and one open-arm study of oral glutathione at 250-500 mg/day reported significant reductions in melanin index versus placebo, and combined topical plus oral glutathione outperformed monotherapy. Only one placebo-controlled study of intravenous glutathione was identified, and roughly half the included studies carried a high risk of bias.
- 03Human clinical2026
A Targeted Metabolomic Assessment of Oral Glutathione Bioavailability and Safety in Humans: A Randomized Crossover Clinical Trial
Solnier J, Du M, Zhang Y, et al. · Antioxidants (Basel) · randomized double-blind crossover, 14 healthy adults, single oral doses of micellar vs standard vs liposomal glutathione, plus 30-day single-arm safety phase at 600 mg/day
Micellar glutathione (300 mg) produced roughly 2.5-fold higher baseline-adjusted whole-blood GSH exposure and peak response than standard glutathione (500 mg), and a higher GSH/GSSG ratio. Thirty days of daily dosing produced no significant change in ALT, AST, ALP or creatinine.
- 04Human clinical2026
Liposomal glutathione outperforms plain glutathione in uptake, cell regeneration and systemic availability: evidence from cellular and human models
Prasad KN, Chandrashekar C, Karthik Y, et al. · British Journal of Nutrition · HEK293T cell assays plus parallel-arm open-label human pharmacokinetic study, 12 healthy adults (6 per arm), single 1 g oral dose
The liposomal formulation reached a maximum plasma concentration approximately six times higher than plain glutathione, showed bimodal absorption and retained plasma levels above 500 ng/mL at 24 hours. Cellular uptake was about 1.9-fold higher in vitro.
- 05Human clinical2026
Formulation-dependent differences in systemic glutathione availability: Comparative pharmacokinetics of orally dissolving film and tablet formulations in healthy adults
Jung ES, Jang HY, Jung SJ, et al. · European Journal of Pharmaceutics and Biopharmaceutics · randomized open-label crossover single-dose 300 mg pharmacokinetics, plus 4-week supplementation at 100 mg/day, healthy adults (CRIS KCT0011710)
Plasma glutathione concentrations were higher with the orally dissolving film than with tablets, reaching significance at 4 and 6 hours, with a longer time to maximum concentration. The authors described only a trend toward greater overall systemic exposure.
- 06Human clinical2023
Supplementing Glycine and N-Acetylcysteine (GlyNAC) in Older Adults Improves Glutathione Deficiency, Oxidative Stress, Mitochondrial Dysfunction, Inflammation, Physical Function, and Aging Hallmarks: A Randomized Clinical Trial
Kumar P, Liu C, Suliburk J, et al. · The Journals of Gerontology, Series A: Biological Sciences and Medical Sciences · placebo-controlled randomized trial, 24 older adults randomised to GlyNAC or isonitrogenous alanine placebo for 16 weeks, plus 12 young adults given GlyNAC for 2 weeks
Older adults had baseline glutathione deficiency, elevated oxidative stress, mitochondrial dysfunction, inflammation, insulin resistance and impaired physical function relative to young adults; GlyNAC supplementation improved these measures over 16 weeks. The trial was small and single-centre.
- 07Human clinical2018
Oral supplementation with liposomal glutathione elevates body stores of glutathione and markers of immune function
Sinha R, Sinha I, Calcagnotto A, et al. · European Journal of Clinical Nutrition · 1-month open pilot study, 12 healthy adults, oral liposomal glutathione 500 or 1000 mg/day
Glutathione increased by up to 40% in whole blood and 100% in peripheral blood mononuclear cells by 2 weeks, alongside a 35% fall in plasma 8-isoprostane. No differences were detected between dose groups, and the study was uncontrolled with limited statistical power.
- 08Human clinical2017
Phase IIb Study of Intranasal Glutathione in Parkinson's Disease
Mischley LK, Lau RC, Shankland EG, et al. · Journal of Parkinson's Disease · double-blind placebo-controlled trial, 45 participants with Hoehn & Yahr stage 1-3 Parkinson's disease, intranasal glutathione 100 or 200 mg three times daily for 3 months
All cohorts including placebo improved, and neither glutathione dose was superior to placebo on total or motor UPDRS scores. One participant in the high-dose group developed cardiomyopathy.
- 09Human clinical2017
Efficacy of glutathione for the treatment of nonalcoholic fatty liver disease: an open-label, single-arm, multicenter, pilot study
Honda Y, Kessoku T, Sumida Y, et al. · BMC Gastroenterology · open-label single-arm multicentre pilot, 34 enrolled (29 completed) NAFLD patients, oral glutathione 300 mg/day for 4 months after a 3-month lifestyle run-in
Alanine aminotransferase decreased significantly after 4 months of oral glutathione, along with triglycerides, non-esterified fatty acids and ferritin. There was no control arm, so the contribution of the preceding lifestyle intervention could not be separated.
- 10Human clinical2015
Randomized controlled trial of oral glutathione supplementation on body stores of glutathione
Richie JP Jr, Nichenametla S, Neidig W, et al. · European Journal of Nutrition · 6-month randomized double-blind placebo-controlled trial, 54 non-smoking adults, oral glutathione 250 or 1000 mg/day
At 6 months, glutathione rose about 30-35% in erythrocytes, plasma and lymphocytes and 260% in buccal cells in the high-dose group, with dose- and time-dependent effects that returned to baseline after a 1-month washout. Natural killer cell cytotoxicity increased more than twofold versus placebo at 3 months.
- 11Human clinical2012
Glutathione as an oral whitening agent: a randomized, double-blind, placebo-controlled study
Arjinpathana N, Asawanonda P · Journal of Dermatological Treatment · randomized double-blind placebo-controlled trial, 60 healthy adults in Bangkok, oral glutathione 500 mg/day for 4 weeks
Melanin indices decreased at all six measured sites in the glutathione arm, reaching statistical significance versus placebo at two sites (right face and sun-exposed left forearm). Both arms were well tolerated, and the authors noted that long-term safety was not established.
- 12Human clinical1996
Reduced intravenous glutathione in the treatment of early Parkinson's disease
Sechi G, Deledda MG, Bua G, et al. · Progress in Neuro-Psychopharmacology & Biological Psychiatry · open-label uncontrolled study, 9 patients with early untreated Parkinson's disease, intravenous glutathione 600 mg twice daily for 30 days
All patients improved on two disability rating scales, with a reported 42% decline in disability that persisted 2-4 months after discontinuation. The study had no placebo control, no blinding and a sample of nine.
- 13Review2026
Intravenous longevity therapy: a critical review of evidence, mechanisms, and clinical utility
Godic A, Townsend J · Acta Dermatovenerologica Alpina, Pannonica et Adriatica · critical review of intravenous high-dose vitamin, amino acid, glutathione and NAD+ infusion protocols marketed as longevity therapy
Available data came mainly from preclinical models and small clinical series in disease-specific or aesthetic contexts, with scarce and underpowered placebo-controlled trials and substantial heterogeneity of infusion protocols. The authors concluded that intravenous longevity therapy, including glutathione infusion, should be regarded as experimental rather than evidence-based.
- 14Review2026
Efficacy and Safety of Glutathione Supplementation in Patients with HIV Infection and HIV-Tuberculosis Co-Infection
Dawi J, Affa S, Au S, et al. · Nutrients · review of mechanistic studies, clinical trials and translational research on glutathione and precursor supplementation in HIV and HIV-tuberculosis co-infection
Persistent glutathione deficiency was described in HIV infection despite effective antiretroviral therapy, contributing to immune dysfunction and inflammation, and was reported as further exacerbated in HIV-tuberculosis co-infection. The authors concluded that glutathione repletion by direct supplementation or precursor strategies showed supportive but not definitive evidence.
- 15Review2025
Exploring the Safety and Efficacy of Glutathione Supplementation for Skin Lightening: A Narrative Review
Alzahrani TF, Alotaibi SM, Alzahrani AA, et al. · Cureus · narrative review of oral, topical and intravenous glutathione in dermatology
Oral administration was associated with significant but variable reductions in melanin with limited side effects, while intravenous glutathione was linked to serious safety concerns including anaphylaxis and hepatotoxicity, compounded by the absence of standardised dosing protocols. The authors called for caution with intravenous use pending large-scale trials.
What this evidence does not establish.
Intravenous glutathione is not an approved treatment for skin lightening, anti-ageing or general wellness in any major jurisdiction, and controlled efficacy data for infusion are essentially limited to a single placebo-controlled dermatology study; reported harms include anaphylaxis, hepatotoxicity and cardiomyopathy in one intranasal trial participant. Oral bioavailability remains disputed and highly formulation-dependent, trials are typically 4 weeks to 6 months in fewer than 60 participants, effects on blood glutathione revert after washout, and there are no long-term safety data for repeated parenteral administration.
Common questions about the research.
- What is glutathione?
Glutathione is the tripeptide gamma-L-glutamyl-L-cysteinyl-glycine, present in most mammalian cells at millimolar concentration. Its gamma-linkage resists ordinary peptidases and its cysteine thiol group carries out its redox chemistry. This product is the reduced form, supplied lyophilised as a 1,500 mg research vial.
- What is the difference between GSH and GSSG?
GSH is the reduced form with a free thiol; GSSG is the oxidised disulfide dimer formed when two GSH molecules donate electrons. Glutathione reductase converts GSSG back to GSH using NADPH, and the ratio between the two is the standard laboratory marker of cellular redox state.
- Why do the oral and intravenous studies disagree?
Oral glutathione is substantially broken down in the gut and resynthesised intracellularly from cysteine, glutamate, and glycine, so oral dosing does not deliver the intact tripeptide to circulation the way parenteral routes do. One randomised oral trial reported increased body stores while a crossover study of oral supplementation found no change in the oxidative-stress biomarkers it measured — a discrepancy the literature attributes largely to route and bioavailability.
Available from our catalog
For research purposes only. Not for human consumption, diagnosis, treatment, or prevention of any condition. Nothing on this page is medical advice, and no study summarised here should be read as a recommendation.