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Nac6.0
NAC Research
Likely helps
810 peer-reviewed studies
What the evidence says
Probably helps
NAC helped in about half (2/3) of the studies that measured an effect — promising, but not unanimous.
Most evidence is from high-quality meta-analyses and randomised trials published 1982–2026 with a typical study size of 701 participants.
Based on 806 studies · 132 meta-analyses · 609 RCTs · 9,146 total participants
Confidence
High confidence
What the studies found
2helped1unclear· 803 more without graded effect data
Fertility & reproductiveIn a meta-analysis of 15 trials in 2,330 women, NAC did not significantly raise pregnancy or ovulation rates, and it did worse than metformin. · 4-12 weeks
Too few graded studies19 studies
Women's healthIn PCOS, a meta-analysis found effects on progesterone and LH, and one trial improved ovulation induction · 4-8 weeks
Too few graded studies15 studies
Neuroprotection & brain agingRaises glutathione. The only cognition data are working memory as an add-on in schizophrenia · 8-12 weeks
Too few graded studies11 studies
Safety profile
Too few graded studies9 studies
Immune supportRaises glutathione. Immune data are exercise markers and TB adjunct studies, not infections in healthy people · 2-4 weeks
Too few graded studies5 studies
Digestive health
Too few graded studies5 studies
Glucose & metabolic
Too few graded studies5 studies
Men's vitality
Too few graded studies2 studies
Anxiety & stressGlutamate modulation shows benefits for OCD and anxiety disorders · 4-8 weeks
Too few graded studies1 study
By the numbers
Pulled from 27 studies with measurable effects
Likely real effects
100%
across studies
People studied
9,146
typical study: 701 people
Strongest designs
741
132 pooled, 609 randomised
Showed benefit
67%
2/3 studies
How long studies ran
Under a week
1
3+ months
2
Populations Studied
Women with PCOS1
Patients on anti-tuberculosis drugs1
Patients with psychiatric problems, particularly bipolar disorder1
Patients with substance use disorders1
Steady research
198 studies in the last 5 years · Latest meta-analysis: 2026
198220042026
1Meta-Analysis2025
In plain English: This integrated evidence substantiates NAC's potential as a critical adjuvant therapy.
Varikasuvu SR, Manne M, Kumar S, Mudgal SK, Raj V, Varshney S, Gupta P, Grover A, Goyal C, Lal V, Singh H, Lisa M, Saransh Workshop Members. · Cellular and molecular biology (Noisy-le-Grand, France) (2025)
NAC significantly reduced mortality (RR=0.59, 95% CI 0.39-0.88, p=0.01; I²=62%), indicating a 41% decreased risk of death.
Six RCTs (656 patients) showed improved recovery/discharge rates (RR=1.09, 95% CI 1.03-1.14, p=0.003; I²=0%).
These findings suggest NAC significantly improves clinical outcomes in COVID-19 and may inhibit viral replication by targeting Mpro.
2Progesterone levels in women with PCOSMeta-AnalysisCited 10×n=2,515 · very large study2025
In plain English: NAC had a major effect on progesterone, endometrial thickness, and LH levels in women with PCOS.
Viña I et al. · Nutrients (2025)
Huge benefit
← WorseNo effectBetter →
Likely real
Twenty-two studies (n = 2515) were included.
NAC was associated with a statistically significant increase in progesterone (SMD 0.95, 95% CI: 0.13-1.77, p = 0.02) and endometrial thickness (SMD 0.58, 95% CI: 0.10-1.06, p = 0.02) compared to the placebo and other drugs.
LH levels were significantly increased by NAC compared to metformin (SMD 0.67, 95% CI: 0.23-1.12, p = 0.003).
3Incidence of anti-TB drug induced liver injuryMeta-AnalysisCited 13×n=3,423 · very large study2023
In plain English: The NMA indicated that supplementation of Turmeric plus Tinospora cordifolia (RR 0.07; 95% CI 0.02 to 0.28), and N-acetyl cysteine (NAC) (RR 0.09; 95% CI 0.01 to 0.75) significantly reduced the incidence of anti-TB drug-induced liver injury compared with placebo.
Akkahadsee P et al. · Scientific reports (2023)
Huge benefit
← WorseNo effectBetter →
The NMA indicated that supplementation of Turmeric plus Tinospora cordifolia (RR 0.07; 95% CI 0.02 to 0.28), and N-acetyl cysteine (NAC) (RR 0.09; 95% CI 0.01 to 0.75) significantly reduced the incidence of anti-TB DILI compared with placebo.
In addition, poly herbal product significantly reduced alkaline phosphatase (ALP) (MD - 21.80; 95% CI - 33.80 to - 9.80) and total bilirubin (Tbil) compared with placebo (MD - 0.51; 95% CI - 0.76 to - 0.26).
There was no statistically significant difference in the occurrence of AEs in any intervention.
4Depressive symptoms in patients with psychiatric problemsMeta-AnalysisCited 6×n=904 · large study2024
In plain English: Our findings indicate that adjunctive NAC can ameliorate depressive symptoms in patients with psychiatric problems, particularly bipolar disorder.
Peng TR et al. · General hospital psychiatry (2024)
Our findings indicate that adjunctive NAC can ameliorate depressive symptoms in patients with psychiatric problems, particularly bipolar disorder.
However, large-scale clinical trials were needed to substantiate our results due to the wide CI value.
5Substance use cravingsMeta-AnalysisCited 4×n=623 · large study2024
In plain English: NAC did not significantly outperform placebo in reducing symptoms of craving in the meta-analysis (SMD = 0.189, 95% CI = -0.015-0.393).
Winterlind EL et al. · Addiction biology (2024)
No clear effect
← WorseNo effectBetter →
The most targeted substance in the clinical trials was alcohol (3/9; 33.3%), followed by tobacco (2/9; 22.2%) and multiple substances (2/9; 22.2%).
NAC did not significantly outperform placebo in reducing symptoms of craving in the meta-analysis (SMD = 0.189, 95% CI = -0.015-0.393).
Heterogeneity was very high in the meta-analysis (99.26%), indicating that findings may have been influenced by clinical or methodological differences in the study protocols.