Evidence-based·Last reviewed May 30, 2026·How we grade evidence

Glutathione

ProteinTripeptideBest taken away from food

Useful mainly for targeted antioxidant support or documented low glutathione. For raising intracellular glutathione, NAC is usually better supported.

Quick decision guide

May help most

People with documented low glutathione (e.g., older adults, chronic illness) seeking antioxidant support; liver health in specific conditions

Common dosing range

250–500 mg/day (liposomal); 500–1,000 mg/day oral; NAC 600–1,800 mg/day is better-evidenced for raising intracellular levels

When to expect effects

Weeks (if absorbed effectively)

Watch out for

Standard oral forms have poor bioavailability; liposomal or sublingual forms show better absorption but are not universally proven; cancer patients should consult oncologist before use

Evidence snapshot

Direct glutathioneLow

Limited evidence for direct oral benefit

Liposomal / sublingual formsEmerging

Some promise for better absorption

NAC precursorBetter supported

Stronger evidence for raising intracellular glutathione

What is it

Glutathione is a tripeptide made of glutamate, cysteine, and glycine that is synthesized in every human cell. It is the body's most abundant intracellular antioxidant and a central player in detoxification, immune function, and cellular redox balance.

Is it worth it for you?

Use this as a quick fit check, not a diagnosis.

Worth considering if…

You are an older adult with confirmed low cellular glutathione and want antioxidant support
You have non-alcoholic fatty liver disease and want an adjunct with limited risk
You prefer direct glutathione supplementation over NAC for convenience

Probably skip if…

You expect dramatic detoxification or disease-reversal effects at typical doses
You have cancer or are undergoing chemotherapy without oncologist approval
You have asthma and are considering inhaled or nebulized forms (bronchospasm risk)

Evidence at a glance

oxidative stress reduction

Limited Evidence
Effect
Modest increases in plasma GSH and reductions in oxidative stress markers in some trials
Best fit
Older adults and people with conditions associated with depleted glutathione
Time
Weeks

immune function support

Limited Evidence
Effect
Small changes in immune cell markers; no robust clinical endpoint data
Best fit
Older adults with immune senescence
Time
Weeks

Evidence for 2 uses

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

oxidative stress reduction

Biomarker support
Limited Evidence

Small RCTs of oral and liposomal glutathione show modest increases in plasma glutathione concentrations and reductions in oxidized glutathione ratios (GSSG/GSH). Liposomal forms have demonstrated better absorption than standard oral formulations in comparative studies. These are biomarker-level outcomes; whether they translate to measurable clinical health benefits in otherwise healthy people is not established.

Effect size
Modest increases in plasma GSH and reductions in oxidative stress markers in some trials
Time to effect
Weeks
Best fit
Older adults and people with conditions associated with depleted glutathione
Less likely
Healthy young adults with normal glutathione levels

Bottom line: Liposomal glutathione raises plasma GSH levels modestly; clinical significance of this biomarker change is uncertain.

SourceKumar et al., 2023 — PMC

immune function support

Biomarker support
Limited Evidence

Glutathione is required for optimal lymphocyte proliferation and NK cell activity; its depletion in aging and chronic disease correlates with impaired immune function. One RCT showed that oral glutathione (250–1,000 mg/day for 6 months) increased NK cell cytotoxicity and lymphocyte proliferation. These are surrogate immune markers, not clinical infection or disease outcomes.

Effect size
Small changes in immune cell markers; no robust clinical endpoint data
Time to effect
Weeks
Best fit
Older adults with immune senescence

Bottom line: Interesting immune marker signals in limited trials; no clinical infection or outcome data in otherwise healthy people.

SourceBumrungpert et al., 2018 — PubMed

How it works

Glutathione cycles between reduced (GSH) and oxidized (GSSG) forms. In its reduced form, GSH donates electrons to neutralize reactive oxygen species, peroxides, and free radicals; the enzyme glutathione peroxidase uses GSH to convert hydrogen peroxide into water. After donating an electron, GSH becomes GSSG and is recycled back to its active form by glutathione reductase using NADPH. Beyond direct antioxidant activity, glutathione is a substrate for glutathione S-transferases, a family of enzymes that conjugate toxins, drugs, and metabolic byproducts to make them water-soluble and excretable in bile and urine. It also regenerates oxidized vitamins C and E and participates in DNA synthesis and immune cell function. Oral glutathione supplementation has historically been considered poorly bioavailable because the tripeptide is broken down in the digestive tract. Newer formulations, including liposomal, sublingual, and acetylated forms, have been developed to improve absorption. The most reliable way to raise intracellular glutathione is often through supplying its precursor amino acid cysteine, typically as N-acetylcysteine (NAC).

How to take it

1. Typical dose
250–500 mg/day liposomal glutathione; 500–1,000 mg/day standard oral (reduced form)
2. Timing
On an empty stomach for standard oral forms (30 minutes before meals or 2 hours after); liposomal forms can be taken with or without food
3. With food
Standard oral: empty stomach; liposomal: flexible
4. Split dosing
Can split into morning and evening doses for steady supply
5. How long to try
8–12 weeks minimum to assess subjective or lab changes

What to track

Subjective energy and fatigue
Liver enzymes (ALT, AST) if using for liver support
Skin changes if monitoring for pigmentation effect
Any respiratory symptoms if using non-oral forms

4 commercial forms

Compare the main delivery options and what they’re best suited for.

Reduced glutathione (GSH)

Inexpensive but may not reliably raise intracellular glutathione.

Standard oral form; bioavailability is poor due to digestive breakdown.

Liposomal glutathione

Higher bioavailability than standard oral; clinical evidence of raised blood levels.

Encapsulated in phospholipid liposomes to protect from digestion.

S-acetyl glutathione

Marketed for improved absorption; clinical evidence is emerging but limited.

Acetylated form designed to resist digestive breakdown.

N-acetylcysteine (NAC)

Often more effective at raising intracellular glutathione than direct supplementation. Well-studied for many indications.

Cysteine precursor; supports endogenous glutathione synthesis.

Safety

Know the common side effects, key cautions, and who should avoid it.

Common side effects

bloatinggasmild GI upset

Serious risks

  • Bronchospasm with inhaled/nebulized forms in people with asthma

  • Possible interference with chemotherapy efficacy (consult oncologist before use)

Who should avoid it

  • People with asthma (avoid inhaled or nebulized forms)
  • People undergoing cancer chemotherapy (discuss with oncologist first)
  • People with sulfa allergy (use with caution — glutathione contains sulfur)

Pregnancy & breastfeeding

Oral glutathione as a supplement has limited safety data in pregnancy; discuss with a clinician before use.

Interactions

chemotherapy agentsMajor

Glutathione may neutralize oxidative mechanisms of some chemotherapy drugs, potentially reducing efficacy; oncologist approval required

acetaminophen (paracetamol)Moderate

Acetaminophen overdose depletes glutathione causing liver failure; NAC (not oral glutathione) is the medical antidote. Supplemental glutathione at normal doses does not protect against overdose.

Documented interactions

Evidence-graded pair pages with sources, dosing notes, and timing guidance — a complement to the narrative section above.

Beneficial pairs (2)

+ vitamin c

synergy

Glutathione and vitamin C participate in the same cellular antioxidant network and help regenerate one another. When vitamin C is oxidised to dehydroascorbate, glutathione donates electrons to convert it back to active ascorbate; in turn, vitamin C helps keep glutathione in its active reduced form. The two are commonly supplemented together and the combination is well tolerated, though clinical benefit beyond the established biochemistry is modest and not consistently proven.

+ nac

synergy

NAC (N-acetylcysteine) supplies cysteine, the rate-limiting building block the body uses to make its own glutathione, while supplemental glutathione adds to the existing pool. Both support antioxidant defense, and the pairing is generally well tolerated. Human trial evidence for raising glutathione comes mainly from NAC (often with glycine, as GlyNAC), not from combining NAC with oral or liposomal glutathione, and no study has shown the pair works better than either one alone.

See all 2 Glutathione interactions →

Food sources

Asparagus

Amount
1 cup cooked
%DV
—

Spinach

Amount
1 cup cooked
%DV
—

Avocado

Amount
1/2 medium
%DV
—

Okra

Amount
1 cup cooked
%DV
—

Garlic

Amount
1 clove
%DV
—

Whey protein (cysteine source)

Amount
1 scoop (25-30g)
%DV
—

Eggs (cysteine source)

Amount
2 large
%DV
—

Choosing a product

What to look for on the label — and what to be skeptical of.

Look for…

Reduced form (GSH) specified — oxidized glutathione (GSSG) is not therapeutically active
Liposomal delivery for better absorption versus standard capsules
Third-party tested for purity and stability (glutathione degrades quickly if poorly stored)

Be skeptical of…

Whitens skin or reduces melanin production — evidence is very weak and effect is not reliable
Detoxifies the body from heavy metals or environmental toxins
Reverses aging or replaces endogenous antioxidant systems
Equivalent to NAC for raising intracellular glutathione — NAC is better-evidenced for this

Frequently asked questions

Does oral glutathione actually work?⌄

Older studies suggested poor bioavailability, but newer research, especially with liposomal and acetylated forms, indicates oral glutathione can raise blood levels. For raising tissue glutathione, N-acetylcysteine remains a well-supported alternative.

What's the difference between glutathione and NAC?⌄

Glutathione is the active tripeptide antioxidant. NAC (N-acetylcysteine) is a precursor that supplies cysteine, the limiting amino acid for glutathione synthesis. NAC is typically cheaper, better studied, and reliably raises intracellular glutathione.

Can glutathione lighten skin?⌄

Some small studies suggest a modest skin-lightening effect, but evidence is low quality. Intravenous glutathione for cosmetic skin lightening has not been proven safe or effective and is not FDA-approved for this use.

Is it safe to take glutathione daily?⌄

Short-term daily use of oral glutathione appears safe in healthy adults. Long-term safety data are limited. Consult a clinician if you have underlying conditions or are taking medications.

Should glutathione be taken on an empty stomach?⌄

Standard oral glutathione is best taken on an empty stomach to minimize digestive degradation. Liposomal forms tolerate food better. Sublingual forms should be held under the tongue away from meals.

References by claim

oxidative stress reduction

Kumar et al., 2023 — PMC (2023) link

immune function support

Bumrungpert et al., 2018 — PubMed (2018) link

Track Glutathione with Pilora

Set up dose reminders, check interactions, and join the community in the Pilora iPhone app.

Coming to App Store
Evidence-based·Last reviewed May 30, 2026·Evidence current as of May 30, 2026·How we grade evidence

Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.