PeptideCompareGlutathione — EU research guide.
Glutathione (GSH) is the most abundant endogenous antioxidant tripeptide in human cells, consisting of glutamate, cysteine and glycine. It is central to oxidative stress defence, detoxification and immune function.
What is Glutathione?
Glutathione exists in reduced (GSH) and oxidised (GSSG) forms. GSH is synthesised in cells from its constituent amino acids and acts as a cofactor for glutathione peroxidase (removing H₂O₂), glutathione S-transferase (detoxification) and thioredoxin reduction. Depletion is associated with aging, chronic disease and oxidative stress states. Injectable glutathione is used in clinical settings for specific indications.
What does the research show?
Oral bioavailability of glutathione is limited — it is largely degraded in the GI tract. IV or liposomal delivery achieves meaningful plasma elevation. Clinical research in Parkinson's disease, mitochondrial disorders and chemotherapy-related neuropathy has yielded mixed results. Skin brightening via melanin pathway modulation is actively studied, particularly in Asian dermatology literature. N-acetylcysteine (NAC) is often studied as a more bioavailable precursor.
EU legal status
Glutathione is a legal food supplement ingredient in the EU. Injectable research-grade glutathione is available for laboratory and clinical research. IV glutathione for skin brightening is used off-label in some contexts — regulatory status varies by member state.
Molecular information
Pharmacokinetics
Potency retained over time
Each line is one storage condition: it starts at 100% and falls as potency is lost. Above the dashed 80% line the material is considered reliable — hover for exact values.
⚠ Modelled per compound from molecular structure — chain length, cyclisation, oxidation- and deamidation-prone residues and light sensitivity. Indicative only, not lab-measured per batch.
Glutathione across EU suppliers
COA-verified EU vendors · Updated monthly
Frequently asked questions
What is Glutathione? ▾
Glutathione is a tripeptide (Glu-Cys-Gly) that exists in reduced (GSH) and oxidised (GSSG) forms. GSH acts as a cofactor for glutathione peroxidase, glutathione S-transferase and thioredoxin reduction, and its depletion is associated with aging and oxidative stress.
Why is oral glutathione considered poorly bioavailable? ▾
Oral glutathione is largely degraded in the GI tract, so IV or liposomal delivery is used to achieve meaningful plasma elevation.
What does the research show? ▾
Clinical research in Parkinson's disease, mitochondrial disorders and chemotherapy-related neuropathy has yielded mixed results, while skin brightening via melanin-pathway modulation is actively studied.
Is glutathione legal in the EU? ▾
Oral glutathione is a food supplement, while IV or injectable glutathione is handled as a research compound.
Is glutathione banned in sport? ▾
No. It is not prohibited by WADA.
What is the difference between GSH and GSSG? ▾
GSH is the reduced, active antioxidant form and GSSG is the oxidised form. The ratio between them reflects cellular oxidative status.
References
- The main positive human trial: a 6-month randomised, placebo-controlled study in 54 healthy adults reported that oral glutathione at 250 or 1000 mg/day raised body stores of glutathione in blood and cells. This is the study most often cited to argue that oral GSH is bioavailable. Richie JP Jr, Nichenametla S, Neidig W, et al. Eur J Nutr. 2015;54(2):251–263. DOIPubMed 24791752
- The counter-evidence that vendors omit: an earlier randomised, double-blind, placebo-controlled trial (500 mg twice daily for 4 weeks) found no significant change in glutathione status or oxidative-stress biomarkers in healthy adults. Human results on oral GSH genuinely conflict, and dose, duration and which blood fraction is measured all differ between studies. Allen J, Bradley RD. J Altern Complement Med. 2011;17(9):827–833. DOIPubMed 21875351
- A liposomal-formulation pilot in 12 healthy adults reported raised blood glutathione and improved immune markers over 1 month. The trial is small and open to formulation-specific effects; it does not settle the bioavailability question for standard oral glutathione. Sinha R, Sinha I, Calcagnotto A, et al. Eur J Clin Nutr. 2018;72(1):105–111. DOI