Antioxidant

Glutathione

Also called GSH, reduced glutathione, L-glutathione, γ-glutamylcysteinylglycine

Glutathione is a tiny three-amino-acid peptide that every cell makes and that serves as the body's main built-in antioxidant. It is sold as a supplement and given as IV drips at wellness clinics, but oral forms are poorly absorbed and no glutathione product is FDA-approved as a drug.

Early human dataSome small human studies exist; evidence is limited.

All printable flashcards

Drawn from its published sequence: 3 residues, one bead each.

Overview

How it works

Established: cells build glutathione in two ATP-using steps (glutamate-cysteine ligase, then glutathione synthetase). Its cysteine thiol neutralizes reactive oxygen species, and it is the cofactor for glutathione peroxidases and glutaredoxins. It helps detoxify drugs and toxins through glutathione S-transferases (for example, the toxic acetaminophen product NAPQI) and keeps vitamins C and E in their active form. Proposed or weakly supported: that taking glutathione by mouth or IV meaningfully raises cell levels or gives health benefits (such as skin lightening) in healthy people.

What research shows

Oral glutathione is largely broken down in the gut and has poor systemic availability (Witschi et al., Eur J Clin Pharmacol 1992).
Its γ-glutamyl bond protects it from ordinary peptidases inside the body (Wu et al., J Nutr 2004 review).
N-acetylcysteine, a cysteine source, is an approved way to restore glutathione in acetaminophen overdose (Lu 2013 review).

Doses studied in people

No FDA-approved glutathione drug or labeled dose exists. Doses used in supplement studies were not verified for this entry, so none are listed.

Read this first: these are the amounts given to participants in published studies or written on official prescribing labels, reported for reference. They are not recommendations. Trial doses were chosen for specific patients under medical supervision, and a dose that is safe in one person can be harmful in another.

Vial math

Many research vials hold 5 or 10 mg of powder. This table shows how much ends up in each mark on a U-100 insulin syringe for common amounts of added liquid. It is arithmetic only, not a dose.

Vial	Liquid added	Concentration	Per unit (0.01 mL)
5 mg	1 mL	5 mg/mL	50 mcg	Open in calculator
5 mg	2 mL	2.5 mg/mL	25 mcg	Open in calculator
5 mg	3 mL	1.67 mg/mL	16.7 mcg	Open in calculator
10 mg	1 mL	10 mg/mL	100 mcg	Open in calculator
10 mg	2 mL	5 mg/mL	50 mcg	Open in calculator
10 mg	3 mL	3.33 mg/mL	33.3 mcg	Open in calculator

More sizes: all vial sizes · How this works: Syringes and units · Reconstitution guide.

Safety

IV infusions carry the general risks of IV access (infection, infusion reactions); quality of clinic-compounded products varies.
Long-term safety of high-dose oral or IV use in healthy people is not well studied.

Report side effects of any drug or product to the FDA through MedWatch. For a possible poisoning in the US, call Poison Control at 1-800-222-1222.

Legal status

FDA: Not FDA-approved as a drug for any indication. Sold as a dietary supplement (oral).
Compounding: Its status on the FDA 503A bulk drug substances lists was not verified in this pass; check FDA's current 503A list before relying on any compounded product.
Sports (WADA): Not named on the 2026 WADA Prohibited List, but IV infusions or injections totaling more than 100 mL per 12 hours are prohibited (method M2.2) except during hospital treatment, surgery or clinical diagnostic investigations.
Other: Marketed widely online as a supplement and offered in IV clinics.

Rules change often. See Legal status of peptides for how these categories work.

History

Glutathione has been known since the early 20th century, and its biochemistry is well understood. In recent decades it has become a popular supplement and wellness-clinic IV product, without FDA drug approval for any use.

Common questions

What does glutathione do in the body?

Every cell makes it, and it neutralizes harmful reactive oxygen molecules ¹². It also helps clear drugs and toxins, such as the toxic breakdown product of acetaminophen ¹.

Does oral glutathione get absorbed?

Poorly. A 1992 study found oral glutathione is largely broken down in the gut and little reaches the bloodstream ³.

What does the research show?

Its chemistry is well understood, including a special bond that protects it from ordinary enzymes inside the body ¹². Whether taking it by mouth or IV meaningfully raises cell levels in healthy people is only weakly supported ³.

How does it compare to N-acetylcysteine (NAC)?

NAC supplies cysteine, a building block cells use to make glutathione ¹. It is an approved way to restore glutathione in acetaminophen overdose ¹.

Is glutathione banned in sport?

It is not named on WADA's 2026 list, but IV infusions or injections over 100 mL per 12 hours are prohibited except during hospital treatment, surgery or diagnostic tests ⁹⁰.

Related compounds

Cosmetic & skinEarly human dataFlashcard

Argireline (acetyl hexapeptide-8)

acetyl hexapeptide-8 · acetyl hexapeptide-3 (older INCI name)

Argireline is a short lab-made peptide used in anti-wrinkle creams and serums.

Sources

Lu SC. Glutathione synthesis. Biochim Biophys Acta 2013 (PMID 22995213) PubMed review
Wu G et al. Glutathione metabolism and its implications for health. J Nutr 2004 (PMID 14988435) PubMed review
Witschi A et al. The systemic availability of oral glutathione. Eur J Clin Pharmacol 1992 (PMID 1362956) Journal
Glutathione (Wikipedia; formula, CAS) Journal
WADA 2026 Prohibited List Regulatory

Last reviewed 2026-10-25 · How we research · Found an error? See our corrections policy.