Skip to content
How to Take Glutathione: Doses, Timing and Stopping
There is no official dose or time of day for glutathione, so the figure to follow is the one on your label, read against what the trials did: 250 to 1,000 mg a day, every day, for four weeks to six months, measuring blood rather than how people looked or felt.1, 2 The four-week trial, at 1,000 mg a day, found no change in blood glutathione; in the six-month trial, blood glutathione had risen by one month, rose further by six, and was back to baseline a month after stopping.2, 1 No trial has compared morning with night or food with no food, and glutathione has no authorised health claim in Great Britain, so nothing here is a benefit to expect.3 The ingredient is explained in what does glutathione do in the body.
What happens if you take glutathione every day?
What has been measured is blood. Two placebo-controlled daily trials frame it. In the first, 40 healthy adults took 500 mg twice a day for four weeks and nothing changed: red-cell glutathione, its oxidised form, their ratio and two urinary oxidative-stress markers were the same as placebo at week four.2 In the second, 54 non-smoking adults took 250 or 1,000 mg a day for six months; blood glutathione was above baseline at one, three and six months at both doses, and by six months was 30 to 35% higher in red cells, plasma and lymphocytes at 1,000 mg and 17 to 29% higher in blood and red cells at 250 mg.1 Read together, the two trials differ in length as much as in result; the four-week trial reported liver, kidney and blood-count tests unchanged, and the six-month report gives no adverse-event data.2, 1 A 2026 review describes gastrointestinal discomfort as the most reported side effect in the trials and serious toxicity as rare.4 No daily trial has measured a clinical outcome in healthy people. The side effects in full are on glutathione side effects.
How much glutathione did the trials use?
These are trial doses, not a recommendation; a UK supplement label carries its own daily amount and a "do not exceed the stated dose" line, and that is the figure to follow.
| Trial | Dose and form | Duration and people | What was measured |
|---|---|---|---|
| Allen and Bradley 2011 | 1,000 mg a day, as 500 mg twice daily | 4 weeks; 40 adults; placebo | No change in red-cell glutathione or urinary oxidative-stress markers2 |
| Richie 2015 | 250 or 1,000 mg a day | 6 months plus a one-month washout; 54 adults; placebo | Up 17 to 29% at 250 mg and 30 to 35% at 1,000 mg; baseline again after the washout1 |
| Kalamkar 2022 | 500 mg a day with diabetes treatment | 6 months; 125 people with type 2 diabetes | Blood glutathione up, a DNA-damage marker down, within three months5 |
| Sinha 2018 | 500 or 1,000 mg a day, liposomal | 4 weeks; 12 adults; no placebo; maker-funded | Whole blood up to 40% higher by two weeks; no difference between doses6 |
| Jung 2026 | 100 mg a day, dissolving film or tablet | 4 weeks | Both raised circulating glutathione; no adverse events7 |
The 100 mg study and the 250 mg arm both moved blood glutathione and the 1,000 mg four-week trial did not, so dose alone does not predict the measurements; duration matters as much.1, 2, 7 With no authorised claim, a UK label cannot say what any dose, 500 mg included, is for.3 On a different form: in 2026 the European assessors judged S-acetyl glutathione, an acetylated form, safe at 300 mg a day for adults, excluding pregnant and breastfeeding women and children under 10; that figure is not a limit for reduced glutathione.8 Each format, with its study's size, control and funder, is on does liposomal glutathione work.
Is it better to take glutathione in the morning or at night?
Neither has been tested against the other: no randomised trial has compared them, and the six-month trial does not say what time its participants took it.1 The only timing data are single-dose studies: in 1992, seven volunteers took about 3 g in one go and free plasma glutathione did not rise significantly over the next four and a half hours; in 2014, the protein-bound fraction of plasma glutathione rose 60 to 120 minutes after a dose of 50 mg per kilogram while the free fraction did not.9, 10 Those describe the hours after one dose; the months-long trials above measured something else. The practical answer is the hour you will keep: a capsule at night is as reasonable as one at breakfast.
Should you take glutathione with food or on an empty stomach?
No trial has compared the two, and none of the trial abstracts says whether the dose was taken with a meal.1, 2 The label's direction, usually with food or with water, is the maker's instruction and the one to follow; no evidence says waiting a set time before or after eating changes anything. If a capsule makes you feel sick, taking it with a meal is the ordinary first step; ask a pharmacist if it continues.4 Food contains glutathione too; what foods are high in glutathione has the measured figures.
How long does glutathione take to work?
It depends what "work" means; the trials measured one thing. In the six-month trial, blood glutathione was above baseline at the first measurement, one month in, and kept rising to six months, while the four-week trial at 1,000 mg a day found no change at week four.1, 2 In the liposomal pilot (12 people, no placebo group, maker-funded), levels were up after one week and peaked at two; in the diabetes trial the changes were present at three months.6, 5 Nothing beyond blood markers has been measured in healthy adults: no trial recorded energy, skin, sleep or how people felt, so there is no evidence-based timeline for any of those.
How long can you take glutathione?
Six months is the longest placebo-controlled run, so six months is the limit of what the evidence can say.1 No trial has run for years, so "can I take it for life" has no trial answer either way; what exists is a six-month trial whose report gives no adverse-event data, a four-week trial whose safety tests were unchanged, the review's "serious toxicities rare" and EFSA's note that ordinary oral glutathione trials support safety in adults.1, 4, 8 Follow the label's daily amount, and ask a pharmacist or GP first if you are pregnant or breastfeeding (no trial has included either group; EFSA excluded both for the acetylated form), if it is for a child (EFSA excluded under-10s), if you take prescribed medicines, or if you have a liver or kidney condition.8
What happens when you stop taking glutathione?
Your levels go back to where they were. In the six-month trial, participants stopped for a one-month washout and blood glutathione "returned to baseline"; the four-week trial, which found no rise, had nothing to follow.1, 2 That is the only direct measurement: the rise is held up by the daily dose, not banked. Nothing harmful was reported on stopping: glutathione is a molecule your cells make every day, so there is no withdrawal and no taper. The same question for NMN is answered on what happens when you stop taking NMN.
Why does this page give no skin-lightening dose or timeline?
Because glutathione is not licensed for that purpose in the UK and the trials do not support one; what is and is not licensed, what the small trials measured and who to ask are on does glutathione lighten skin, and the drips and injections sold for it on are glutathione injections and drips safe in the UK.
Frequently asked questions
Can I stop taking glutathione after three months?
Yes. Nothing in the trials suggests harm from stopping at any point; within about a month blood glutathione returns to your own baseline, as the six-month trial measured, and the four-week trial found no rise to lose.1, 2
Is 1,000 mg of glutathione a day too much?
It is the highest dose in the controlled trials: 1,000 mg a day for four weeks in 40 adults (five reported wind or loose stools, two flushing, one weight gain; safety blood tests unchanged) and for six months in 54 (no adverse-event data reported).2, 1 That is a trial figure, not a target; follow your label, and ask a pharmacist about anything above it.
Can I take 200 mg of glutathione a day?
200 mg sits between the trial doses: below the 250 mg arm that raised blood glutathione 17 to 29% over six months, above the 100 mg a day that raised circulating glutathione over four weeks, and below the 1,000 mg a day that changed nothing in four weeks.1, 7, 2 Three facts, not a verdict; no trial has tested 200 mg a day.
What is the best age to take glutathione?
No trial has compared ages. The six-month trial enrolled non-smoking adults and the diabetes trial people aged 30 to 78.1, 5 Lower blood glutathione in older adults is a population finding, covered on the glutathione guide, not evidence that any age needs a supplement.
How can I tell if glutathione is working?
Not from how you feel, because no trial measured that. The trials measured glutathione in blood, red cells, plasma and lymphocytes; there is no routine NHS test and no symptom list for low glutathione.1
Sources
- Richie JP Jr, et al. Randomized controlled trial of oral glutathione supplementation on body stores of glutathione. European Journal of Nutrition, 2015. PubMed 24791752.
- Allen J, Bradley RD. Effects of oral glutathione supplementation on systemic oxidative stress biomarkers in human volunteers. Journal of Alternative and Complementary Medicine, 2011. PubMed 21875351.
- Department of Health and Social Care. Great Britain nutrition and health claims (NHC) register. gov.uk.
- Au S, et al. Efficacy and safety of glutathione supplementation in type 2 diabetes and diabetes complications. Nutrients, 2026. PubMed 42451135.
- Kalamkar S, et al. Randomized clinical trial of how long-term glutathione supplementation offers protection from oxidative damage and improves HbA1c in elderly type 2 diabetic patients. Antioxidants, 2022. PubMed 35624890.
- Sinha R, et al. Oral supplementation with liposomal glutathione elevates body stores of glutathione and markers of immune function. European Journal of Clinical Nutrition, 2018. PubMed 28853742.
- Jung ES, et al. Formulation-dependent differences in systemic glutathione availability: comparative pharmacokinetics of orally dissolving film and tablet formulations in healthy adults. European Journal of Pharmaceutics and Biopharmaceutics, 2026. PubMed 42392376.
- EFSA Panel on Nutrition, Novel Foods and Food Allergens. Safety of S-acetyl glutathione as a novel food pursuant to Regulation (EU) 2015/2283. EFSA Journal, 2026. PubMed 42683004.
- Witschi A, et al. The systemic availability of oral glutathione. European Journal of Clinical Pharmacology, 1992. PubMed 1362956.
- Park EY, et al. Increase in the protein-bound form of glutathione in human blood after the oral administration of glutathione. Journal of Agricultural and Food Chemistry, 2014. PubMed 24877771.
General information, not medical advice: follow your label, and ask a pharmacist or GP first in pregnancy, while breastfeeding, for a child, with prescribed medicines or with a liver or kidney condition.
