Quick facts
- Class
- Tripeptide (γ-glutamyl-cysteinyl-glycine)
- Role
- The body's principal intracellular antioxidant
- Studied for
- Oxidative stress, immune & metabolic health, skin
- Common forms
- Oral, liposomal, inhaled, IV; precursors like NAC
- Approval
- Sold as a supplement; not an FDA-approved drug for these uses
- Made from
- Glutamate + cysteine + glycine
- Also raised by
- N-acetylcysteine (NAC) and other precursors
Key takeaways
- Glutathione is the body's master intracellular antioxidant — a tripeptide of glutamate, cysteine, and glycine.
- Levels naturally decline with age and oxidative stress, a key reason it features in aging research.
- Oral glutathione is partly digested, so precursors like NAC are often used to raise levels indirectly.
- Popular IV skin-lightening use is poorly supported and has drawn regulator safety warnings.
- Sold as a supplement — not an FDA-approved drug for antioxidant or cosmetic uses.
Overview
Glutathione (GSH) is a tripeptide made from the amino acids glutamate, cysteine, and glycine, and it is the body's most abundant intracellular antioxidant. Unlike most peptides discussed here, it is produced naturally in every cell, and its levels tend to decline with age, illness, and oxidative stress.[1]
It is sold widely as a supplement — oral, liposomal, inhaled, and intravenous — and is heavily marketed for everything from “detox” to skin lightening. The science supports its central biological role, but many consumer claims run ahead of the human evidence.
How it works
- Direct antioxidant. Neutralizes reactive oxygen species and is the substrate for glutathione peroxidase enzymes that defend cells against oxidative damage.[1][3]
- Antioxidant recycling. Helps regenerate other antioxidants such as vitamins C and E.
- Detoxification. Conjugates toxins and drug metabolites (phase II metabolism) to make them easier to excrete, and maintains cellular redox balance.[3]
A practical caveat: oral glutathione is partly broken down in digestion, so much research focuses on precursors (like N-acetylcysteine) that raise glutathione indirectly.
Research & benefits
Aging & oxidative stress
Declining glutathione is associated with aging and many age-related conditions, making it a long-standing focus in gerontology research.[1]
Immune & metabolic health
Glutathione status has been studied in immune contexts such as HIV-associated neurocognitive disorders[2] and in metabolic disease, including roles in type 2 diabetes.[4] It has also been examined in relation to psychiatric and neurological conditions through antioxidant pathways.[3]
Skin lightening
Glutathione is popularly promoted — especially as IV infusions — for skin whitening.
Safety & status
As an endogenous molecule, glutathione is generally well tolerated in supplement form. The bigger concerns are with unapproved intravenous glutathione sold for skin lightening, where sterility, dosing, and product quality are not assured and regulators have issued warnings. Glutathione is sold as a dietary supplement and is not an FDA-approved drug for antioxidant, anti-aging, or cosmetic uses.
Frequently asked questions
Does glutathione lighten skin?
Glutathione is heavily marketed for skin lightening, especially as IV infusions, but the evidence is limited and low-quality, and injectable skin-lightening products have drawn safety warnings from regulators. It is not an established or approved treatment.
Is it better to take glutathione or NAC?
Because oral glutathione is partly broken down in digestion, precursors such as N-acetylcysteine (NAC) are often used to raise glutathione levels indirectly. Which is preferable depends on the goal and is not settled.
Is glutathione FDA-approved?
Glutathione is sold as a dietary supplement and is not an FDA-approved drug for antioxidant, anti-aging, or cosmetic uses. Unapproved injectable glutathione for skin lightening is a particular safety concern.
References
Each source links to its original record — peer-reviewed studies, regulator pages, or reference texts, labelled by type. We summarize findings neutrally; a citation is a reference, not an endorsement, and not a claim that its authors reviewed this page.
- Lapenna D. Glutathione and glutathione-dependent enzymes: From biochemistry to gerontology and successful aging. Ageing Res Rev. 2023. Peer-reviewed study
- Erdos T, Masuda M, Venketaraman V. Glutathione in HIV-Associated Neurocognitive Disorders. Curr Issues Mol Biol. 2024. Peer-reviewed study
- Poladian N, Navasardyan I, Narinyan W, et al. Potential Role of Glutathione Antioxidant Pathways in the Pathophysiology and Adjunct Treatment of Psychiatric Disorders. Clin Pract. 2023. Peer-reviewed study
- Tuell D, Ford G, Los E, et al. The Role of Glutathione and Its Precursors in Type 2 Diabetes. Antioxidants (Basel). 2024. Peer-reviewed study
- Oestreicher J, Morgan B. Glutathione: subcellular distribution and membrane transport (1). Biochem Cell Biol. 2019. Peer-reviewed study