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N-Acetylcysteine

N-Acetylcysteine (NAC) is a prodrug for L-cysteine, which is used for the intention of allowing more glutathione to be produced when it would normally be depleted. Through glutathione buffering, NAC provides antioxidative effects and other benefits.

Our evidence-based analysis on n-acetylcysteine features 107 unique references to scientific papers.

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Last Updated:

Summary of N-Acetylcysteine

Primary information, health benefits, side effects, usage, and other important details

It is invalid to extrapolate from efficacy against the common cold or respiratory tract infections broadly to the novel Coronavirus in particular. For more information, see this page. In any case, we have not reviewed NAC for any viral infection yet, and have no opinion on its efficacy for any of them.

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Human Effect Matrix

Unlocked for Examine Plus members

The Human Effect Matrix summarizes human studies to tell you what effects N-Acetylcysteine has on your body, how much evidence there is, and how strong these effects are.

Full details are available to Examine Plus members.
Grade Level of Evidence
Robust research conducted with repeated double-blind clinical trials
Multiple studies where at least two are double-blind and placebo controlled
Single double-blind study or multiple cohort studies
Uncontrolled or observational studies only
Level of Evidence
? The amount of high quality evidence. The more evidence, the more we can trust the results.
Outcome Magnitude of effect
? The direction and size of the supplement's impact on each outcome. Some supplements can have an increasing effect, others have a decreasing effect, and others have no effect.
Consistency of research results
? Scientific research does not always agree. HIGH or VERY HIGH means that most of the scientific research agrees.
Notes
grade-b Minor Low See all 4 studies
N-Acetylcysteine may reduce some symptoms of COPD by acting as a mucolytic agent and reducing sputum formation, but it does not appear to be effective at aiding the lungs themselves or reducing disease progression.
grade-b - - See all 3 studies
grade-c Notable - See study
NAC supplementation is able to reliably increase glutathione concentrations in cells specifically
grade-c Minor - See study
A decrease in red blood cell (RBC) lipofuscin content has been seen, which is thought to be secondary to reducing lead toxicity and increasing antioxidative defenses
grade-c Minor - See study
NAC supplementation appears to reduce lead bioaccumulation in red blood cells, although the magnitude is statistically significant it is not overly large
grade-c Minor - See study
After about two weeks of 2,400mg NAC supplementation, cigarette usage appears to be reduced voluntarily by around 25%.
grade-c Minor - See study
Preliminary evidence suggests a 31-45% reduction in hair pulling symptoms in persons with trichotillomania when supplementing with 1,200-2,400mg NAC for twelve weeks.
grade-c - - See study
grade-c - - See study
grade-c - - See study
grade-c - - See 2 studies
grade-c - - See study
grade-c - - See study
grade-c - - See study
grade-c - - See study
grade-c - - See study
grade-d Notable - See study
There is a significant reduction of total lesion counts in those who supplement N-Acetylcysteine for at least two months.
grade-d Minor - See study
Self-reported cravings for cocaine during one day of withdrawal appear to be significantly reduced following 12 hours (although acute cravings after 2 hours of supplementation are not affected); this lasts for 24 hours after cessation.
grade-d Minor - See study
Supplementation of 2,400mg appears to reduce symptoms of marijuana addiction, although the reductions in symptoms are not overly prominent based on the limited evidence so far.
grade-d - - See study

Studies Excluded from Consideration

  • Used injections of N-acetylcysteine[1]

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Things to Note

Is a Form Of

Also Known As

N-Acetyl Cysteine, NAC, N-Ac

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Click here to see all 107 references.