You may have read that glutathione drops as we get older, and that this is why so many anti-aging supplements target it.
The research does point that way, but it is less clear-cut than the marketing suggests. Blood levels generally appear to fall with age, brain findings are mixed, and the most-cited explanation comes from a very small study.
This guide explains what the studies show, why levels may fall, and what that does and doesn’t mean for supplements.
The Short Answer
Probably yes, on average, but not for everyone and not in every tissue.
A 2023 systematic review in NeuroImage: Clinical looked at glutathione across adult ages and found that blood glutathione generally decreases with age, except in the oldest-old, who may be a select group of particularly successful agers. Findings for brain glutathione lacked a clear consensus, although most studies pointed to a decline (Detcheverry et al., 2023).
The review covered 35 studies, including 16 blood studies and several brain imaging and post-mortem studies. Its authors noted that the evidence is limited, particularly for the brain, and that whether raising brain glutathione improves brain function remains understudied.
What the Brain Studies Show
Brain findings are the least consistent part of the picture.
Among four brain imaging studies in that review, three reported lower glutathione with age in some regions, while one reported higher levels in others. Of three post-mortem studies, two reported lower levels in some regions and one reported higher levels in a frontal region.
Brain glutathione may differ by region, which adds variability. Anyone claiming that glutathione falls everywhere in the brain as you age is going further than the studies do.
Why Might Glutathione Fall With Age?
The best-known explanation comes from a 2011 study in the American Journal of Clinical Nutrition. Researchers compared 8 older and 8 younger adults using stable-isotope infusions to measure how fast red blood cells make glutathione (Sekhar et al., 2011).
They reported that older adults had lower red blood cell levels of glycine, cysteine, and glutathione, and a markedly lower glutathione synthesis rate. The older adults also had higher markers of oxidative stress. The authors concluded that glutathione deficiency in the elderly occurs because of a marked reduction in synthesis.
Your body makes glutathione from three amino acids: glutamate, cysteine, and glycine. In this study, the shortfall in older adults was linked mainly to low cysteine and glycine (Baylor College of Medicine).
After two weeks of supplementing cysteine and glycine, the older adults’ glutathione levels rose and their oxidative stress markers fell to levels that did not differ from the younger group.
This is intriguing but limited:
- The sample was only 16 people.
- It looked at red blood cells, not other tissues.
- The supplementation phase lasted two weeks and involved only the older group.
- The technology behind this research has been licensed to a company that sells a related supplement, according to the same Baylor article.
We should treat it as a hypothesis, not a settled mechanism.
A Note on Total Glutathione vs. Balance
“Declining glutathione” can mean different things. It can mean less total glutathione, or it can mean a shift in the balance between the active reduced form (GSH) and the oxidized form (GSSG). Our guide on reduced vs. oxidized glutathione explains the difference.
In the 2022 Frontiers in Aging trial we cover in our GlyNAC guide, older adults aged 60 to 85 had higher markers of oxidative damage and oxidized glutathione and a lower reduced-to-oxidized ratio than a young reference group. Their total glutathione was similar to the young group (Lizzo et al., 2022). The young group was a non-treated reference, so that comparison is observational.
So the age-related change may show up in different ways depending on what is measured, which is one reason studies disagree.
Does a Lower Level Mean Something Is Wrong?
Not necessarily. Lower average levels in older groups don’t tell you how any one person is doing, and we found no verified guidance on a routine test that tells you whether your glutathione is “low” in a useful way.
Researchers do link low glutathione with higher oxidative stress. WebMD notes that low levels have been associated with several health conditions, but it doesn’t say what causes the low levels, and an association is not proof that low glutathione causes those conditions.
If you are worried about your health, a healthcare provider is the right person to ask, not a supplement label.
What Can Support Glutathione as You Age?
Because your body makes glutathione from amino acids, the building blocks matter.
Protein and sulfur-rich foods. WebMD notes that sulfur-containing foods such as meat and certain vegetables can boost production. Our guide on foods that boost glutathione naturally covers specific options.
Not relying on glutathione capsules alone. Directly taking glutathione has mixed evidence. A researcher quoted in the Baylor article said glutathione taken directly may not work because it breaks down into its component amino acids, which is why the research focused on supplying cysteine (as NAC) and glycine instead (Baylor College of Medicine). See our guides on NAC vs. glutathione and liposomal vs. sublingual vs. IV glutathione.
What About Supplements for Older Adults?
Evidence for supplements in older adults is early and conflicting.
In the GlyNAC trials, a 16-week trial in 24 older adults reported improved glutathione and several other markers, while a 14-day trial in 117 older adults found no significant difference in total glutathione overall. We break down both in our GlyNAC guide.
None of this shows that supplements slow aging. It shows that glutathione is a reasonable target for research and that the trials so far are small and short.
Safety Considerations
Older adults are more likely to take prescription medication and to have kidney, liver, or heart conditions, which makes checking with a provider especially important.
Sources disagree on drug interactions, and NAC has its own listed precautions. See our guides on glutathione drug interactions and side effects.
When to Talk to a Healthcare Provider
Ask a doctor or pharmacist before starting any glutathione or precursor supplement if you:
- Take prescription medication
- Have a liver, kidney, heart, or lung condition
- Are undergoing chemotherapy or radiation
- Are scheduled for surgery
- Are pregnant or breastfeeding
- Notice new symptoms after starting a supplement
FAQs
Generally, blood glutathione appears to fall with age, according to a 2023 systematic review of 35 studies, though the oldest-old may be an exception and brain findings are mixed.
We could not find a verified age at which this starts. The studies compare broad groups, such as older and younger adults, not a single turning point.
One small study of 16 adults reported that older adults make glutathione more slowly, with lower levels of the amino acids cysteine and glycine. This is a hypothesis from a small study, not a settled explanation.
Not established. A 2-week supplementation in the same small study raised glutathione in older adults, and GlyNAC trials report mixed results, but none shows a lasting or clinically meaningful reversal.
There is no verified guidance that older adults should. Evidence is early, and older adults are more likely to take medication, so it is best to ask a healthcare provider first.
Trials in older adults reported GlyNAC as well tolerated over 2 to 16 weeks, but long-term safety is unknown. Anyone taking medication or managing a health condition should check with a healthcare provider first.
Final Thoughts
Glutathione does appear to decline with age in the blood on average, but the picture is less certain for the brain, and the explanation rests on small studies. A lower average doesn’t mean you are deficient, and it doesn’t prove a supplement will help.
The practical steps are unglamorous: eat enough protein and a varied diet, ask a provider about your individual situation, and treat supplements as experimental. Our best liposomal glutathione supplements guide compares options if you decide to try one.
This article is general information and not a substitute for medical advice. Glutathione supplements are not a treatment or cure for any condition.
References
- Detcheverry F, Senthil S, Narayanan S, Badhwar A. Changes in levels of the antioxidant glutathione in brain and blood across the age span of healthy adults: a systematic review. NeuroImage: Clinical. 2023;40:103503. DOAJ
- Sekhar RV, Patel SG, Guthikonda AP, Reid M, Balasubramanyam A, Taffet G, Jahoor F. Deficient synthesis of glutathione underlies oxidative stress in aging and can be corrected by dietary cysteine and glycine supplementation. Am J Clin Nutr. 2011;94(3):847–853. Houston Methodist Scholars
- Baylor College of Medicine. From the Labs: glutathione deficiency in older adults. BCM Blogs
- Lizzo G, Migliavacca E, Lamers D, et al. A randomized controlled clinical trial in healthy older adults to determine efficacy of glycine and N-acetylcysteine supplementation on glutathione redox status and oxidative damage. Front Aging. 2022;3:852569. Frontiers / BORIS
- WebMD. Glutathione: Health Benefits, Safety Information, Dosage, and More. WebMD