GlyNAC dosage and evidence
Written by Aaron CuhaReviewed Sep 2026
The short answer
GlyNAC is a mix of glycine and NAC, two building blocks the body uses to make its main antioxidant, glutathione. Small studies in older adults found better strength and other ageing markers.
Evidence grade for GlyNAC: Limited. The rule: people have taken it in a published study, but fewer than 100 of them. The sum on this page: 2 completed trials, none stating how many people. A grade counts how much has been done to people, not whether it works.
- People given it
- 0
- Human studies
- 2
- Found nothing
- 0
Dose
No human dose established
Amounts that were given in studies sit in Human evidence on this page. None of them is a personal dose.
2 completed trials, 0 people given it
3 effects reported, 2 unwanted, 1 wanted, by people using it, not a trial
Goal pages: Muscle and strength, Brain, memory and mood
In plain English
In plain English, from Aaron
This is how I would explain it to a friend. The evidence, with the numbers, is further down the page.
GlyNAC is a mix of two supplements, glycine and NAC. Your body uses them to make glutathione, its main antioxidant. Older people often run low on it. GlyNAC gives the body the parts to make more.
What people take it for
- Better strength and walking speed in older age.
- Sharper thinking.
- Less wear and tear on cells.
What studies in people showed
The better study ran 16 weeks and compared GlyNAC with a dummy pill in older adults. People on GlyNAC improved on a range of ageing measures. The dummy group did not. The group was small. An earlier 24-week study in older adults had no comparison group. Glutathione came back up, and strength, walking speed and thinking got better. Those gains faded after people stopped. Both studies came from one research group.
What people report
Reports, not study results
The good
- In the studies on this page, older adults got stronger, walked faster and thought better on it.
The bad
- The gains faded once people stopped taking it.
- The studies are small and come from one research group.
Where these come from: All of it is from the two studies on this page. We have not collected forum or user reports for this one yet.
My bottom line
Cheap, and the results point the right way. But the studies are small and from one group. Get your blood work done, lift, and treat this as a maybe.
An opinion, not a finding. I am a coach, not a doctor.
What it has been measured to do
Measured in people
Goals GlyNAC has been tested for in people, biggest studies first. We count only what the studies on this page say, so the real numbers may be higher.
- Getting strongerno headcount stated · 1 study
- Memory and thinkingno headcount stated · 1 study
What people using it report
Real people telling you what happened to them. Nobody checked it, and the people who post are not a fair sample, so it cannot prove anything works. It is still the best guide on this page to what people actually do with GlyNAC, what they expect, and what goes wrong. The full account, including the negative reports, is below.
34 of the 36 indexed goals have no study of any kind behind GlyNAC
No study in people, animals or cells on this page reports a result for these. That does not prove GlyNAC does nothing for them. It does mean anything you have heard about GlyNAC and one of these did not come from a study cited here.
Show full evidence
What is GlyNAC?
GlyNAC is a mix of glycine and NAC, two building blocks the body uses to make its main antioxidant, glutathione. Small studies in older adults found better strength and other ageing markers.
GlyNAC is a mix of the amino acid glycine and N-acetylcysteine, or NAC. These are the two raw parts the body needs to make glutathione, its main antioxidant. A research group at Baylor tested it in older adults. In a 16-week study against a dummy pill, people on GlyNAC improved on a range of ageing measures and the dummy group did not. In an earlier 24-week study with no comparison group, glutathione came back up, and strength, walking speed and thinking improved. Those gains faded once people stopped. The studies are small, so the results are hopeful but early. It is a supplement mix.
How does GlyNAC work?
It supplies glycine and cysteine so the body can rebuild its glutathione. That lowers wear and tear from oxidation and helps the parts of cells that make energy.
What do people who took GlyNAC report?
This is what real people say happened to them, good and bad. Nobody measured it. A report cannot tell a real effect from the lift people get just from expecting it to work, from a diet or training change made at the same time, or from what was really in the vial. We still put it near the top. It is the next best thing to a study in people: what happens when real people use it, including what goes wrong.
- The striking feature of the discussion is that almost nobody describes actually taking it. The threads are about the research and about which product to buy, and personal accounts of use, good or bad, are absent.
- The practical complaint that does recur is the gap between the amounts used in the studies people are discussing, several grams each of glycine and N-acetylcysteine daily, and the far smaller amount in the branded consumer product, which posters point out is a fraction of it per serving.
- Cost is discussed the other way round from most things here: bulk powder is described as costing very little compared with a branded monthly subscription, so the obstacle people name is not money.
- What people name as the obstacle is the sheer volume, the number of capsules or the taste of the powder, and at least one experienced poster describes that as the reason he did not pursue it after meeting the researcher.
- No side effects are described, and no benefits are described, because no use is described. That absence should be read as an absence of reports rather than as anything about the compound.
Sources: A glycine and N-acetylcysteine supplementation thread on ExcelMale, found through the site's tag index and read directly, September 2026. Nothing above is attributed to any specific post and no post is reproduced.
The evidence, in charts
Fig. 1a · how many people
2studies in people cited, but none says how many people took part
number of people not stated
We do not draw a total, because none of the studies in people on this page gives one. Read the sources below for what each study measured.
We read the number of people from the source lines on this page. Where a line gives no number, we count nothing for it. We do not guess.
Fig. 1b · evidence mix
All 2 sources here are studies in people.
- Study in people · done in people2100%
Counted from the list of sources on this page. It counts only what we cite, so there may be more studies out there. A review counts once, however many studies it sums up.
Fig. 2 · evidence over time
Sources here come from just two years, 2021 and 2023.
Too few different years on this page to draw a timeline.
Fig. 3 · legal status at a glance
US
Not approved
UK
Not approved
AU
Not approved
CA
Not approved
Not approved in any of the four countries shown. This is what the law says, not a verdict on the science. See Legal status below for the full text and any notes.
Fig. 4 · how much does what
Nobody has tested different amounts in people
This chart would show how the effect changes as the amount goes up. For this compound, nobody has measured that in people. So we leave it empty. We will not borrow an animal chart and pretend it works the same in people.
Fig. 5 · what the molecule is
- Kind of compound
- Supplement
- Molecule weight
- Mixture; glycine 75.1 Da plus N-acetylcysteine 163.2 Da
- Half-life
- Stated in words, not a numbersee the exact wording below
- Chain length
- None on file
No amino acid sequence is on file for GlyNAC, which is expected: a supplement is not built from amino acids.
The studies we cite
- Study in people2021Glycine and N-acetylcysteine (GlyNAC) supplementation in older adults improves glutathione deficiency, oxidative stress, mitochondrial dysfunction, inflammation, insulin resistance, endothelial dysfunction, genotoxicity, muscle strength, and cognition: results of a pilot clinical trial
Older adults improved on several fronts, in a study with nobody to compare them against. Over 24 weeks the supplement corrected a shortage of the body's main antioxidant, and strength, walking speed and thinking all improved. The benefits then faded once people stopped, which at least points back at the supplement. Everybody knew they were taking it, and there was no dummy group.
24 weeks of GlyNAC in older adults corrected glutathione deficiency and improved strength, gait speed and cognition; benefits faded after stopping.
- Study in people2023Supplementing glycine and N-acetylcysteine (GlyNAC) in older adults improves glutathione deficiency, oxidative stress, mitochondrial dysfunction, inflammation, physical function, and aging hallmarks: a randomized clinical trial
A proper comparison was run, and the supplement came out ahead of the dummy. Over 16 weeks the people taking it improved on a range of ageing related measures, while the dummy group did not. The sample was small, which is the main limitation. This is the better of the two GlyNAC studies, and it is the one to weigh.
16-week placebo-controlled RCT: GlyNAC, not placebo, improved or corrected multiple aging-related defects; small sample.
Common questions
Has GlyNAC been tested in people?
Yes. 0 people given it across 2 completed trials cited here, 0 of which found nothing. GlyNAC is a mix of glycine and NAC, two building blocks the body uses to make its main antioxidant, glutathione. Small studies in older adults found better strength and other ageing markers.
What is the GlyNAC dosage?
No human dose established. Amounts that were given in studies sit in Human evidence on this page. None of them is a personal dose. 2 completed trials, 0 people given it
Is GlyNAC FDA-approved?
Supplement combination; not an approved drug
How is GlyNAC different from taking glutathione?
Glutathione taken as a pill is poorly absorbed. GlyNAC gives the body the raw parts so it makes its own. Studies suggest that works better.