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Nac8.0
NAC Research
Likely helpsHigh safety
40 peer-reviewed studies
What the evidence says
Likely helps
NAC appears to help in 8 of 9 studies with measurable effects — the evidence leans clearly favourable.
Most evidence is from high-quality meta-analyses and randomised trials published 2015–2026 with a typical study size of 701 participants.
Based on 40 studies · 22 meta-analyses · 4 RCTs · 20,122 total participants
Confidence
High
What the studies found
8helped1unclear· 31 more without graded effect data
Immune supportGlutathione replenishment strengthens immune cell function · 2-4 weeks
Too few graded studies1 study
Glucose & metabolic
Too few graded studies1 study
By the numbers
Pulled from 32 studies with measurable effects
Likely real effects
100%
across studies
People studied
20k
typical study: 701 people
Strongest designs
26
22 pooled, 4 randomised
Showed benefit
89%
8/9 studies
How long studies ran
3+ months
3
Populations Studied
Women with PCOS1
Patients on anti-tuberculosis drugs1
Patients with psychiatric problems, particularly bipolar disorder1
Patients with substance use disorders1
Active research area
32 studies in the last 5 years · Latest meta-analysis: 2026
201520202026
1Progesterone levels in women with PCOSMeta-AnalysisCited 8×n=2,515 · very large study2025
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
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 (SMD 0.71, 95% CI: 0.48-0.94, p < 0.0001).
LH levels were significantly increased by NAC compared to metformin (SMD 0.67, 95% CI: 0.23-1.12, p = 0.003).
NAC had a major effect on progesterone, endometrial thickness, and LH levels in women with PCOS.
2Incidence of anti-TB drug induced liver injuryMeta-AnalysisCited 12×n=3,423 · very large study2023
This meta-analysis examined the effects of NAC.
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.
4Substance use cravingsMeta-AnalysisCited 3×n=623 · large study2024
Addiction Biology published by John Wiley & Sons Ltd on behalf of Society for the Study of Addiction.
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.
5H. pylori eradicationMeta-AnalysisCited 4×n=1,167 · large study2022
Adjuvant NAC plus standard treatment protocols are not superior to standard treatment protocols for H. pylori eradication.
Biswas DP et al. · Clinics and research in hepatology and gastroenterology (2022)
Adjuvant NAC plus standard treatment protocols are not superior to standard treatment protocols for H. pylori eradication.
These findings are consistent with the use of adjuvant NAC with 'currently used standard treatment protocols' (clarithromycin-based triple therapies) and also with adjuvant NAC used in the treatment of naïve patients.
6Recovery biomarkers (CK-MB)Meta-AnalysisCited 1×n=1,388 · large study2022
However, subgroup analyses based on NAC dosage indicated the meaningful effect of NAC on CK-MB at the dosage of ≥100 mg/kg.
Nejati M et al. · Journal of food biochemistry (2022)
PRACTICAL APPLICATIONS: Previous studies on the influence of NAC administration on recovery biomarkers have presented conflicting results.
This systematic review and meta-analysis offers a broad range of detailed information on the influence of chronic and acute NAC supplementation outcomes regarding recovery biomarkers.
Overall, the results support that NAC supplementation may not be effective in improving recovery biomarkers.
7Treatment of idiopathic asthenozoospermiaMeta-AnalysisCited 13×n=621 · large study2021
Moreover, NAC has a positive effect on sperm concentration and ejaculate volume, whereas no obvious effect was observed in serum hormones.
Wei G et al. · American journal of men's health (2021)
Likely real
Besides, NAC had a significantly greater increase in sperm concentration (p < .00001) and ejaculate volume (p = .002) compared with the placebo group, and there was no significant difference in LC/LAC.
For the analysis of serum hormones, NAC had no obvious differences in improving the serum testosterone, luteinizing hormone, follicle-stimulating hormone, and prolactin compared with non-treatment group.
Conclusively, LC/LAC and NAC showed a greater improvement in sperm motility and normal morphology.
8Disease activity in rheumatoid arthritisMeta-AnalysisCited 4×n=204 · medium study2024
Conclusion This meta-analysis demonstrated the efficacy of NAC in reducing inflammatory markers, improving joint tenderness, and swelling in patients with RA.
He T et al. · British journal of hospital medicine (London, England : 2005) (2024)
Noticeable benefit
← WorseNo effectBetter →
The results indicated that NAC alleviated disease activity in RA patients (Disease Activity Score 28-erythrocyte sedimentation rate (DAS28-ESR): mean difference (MD) = 0.54).
10Chronic bronchitis exacerbationsMeta-AnalysisCited 7×n=775 · large study2019
There is a role for NAC treatment in the management of CB by reducing symptoms and exacerbations compared with placebo, without increasing the risk of adverse effects.
Wei J et al. · Advances in therapy (2019)
Noticeable benefit
← WorseNo effectBetter →
Likely real
The pooled analysis demonstrated significant evidence that NAC reduced the frequency of CB exacerbations (RR = 0.81, 95% CI 0.69-0.93, P = 0.004).
Patients treated with NAC had significant symptom improvement compared with controls (RR = 1.68, 95% CI 1.13-2.52, P = 0.01).
NAC did not significantly increase the risk of adverse effects compared with placebo (RR 0.86, 95% CI 0.67-1.09, P = 0.22).
12Lung function and sputum conversionSystematic ReviewCited 2×2025
Most adverse effects reported were mild and manageable, indicating a favourable safety profile for both agents.</sec><sec><title>CONCLUSIONS</title>GSH and NAC show promise as adjunctive therapies in TB management, demonstrating improvements in lung function, sputum conversion, and hepatoprotection while also enhancing immune responses.</sec>.
Nasiri MJ et al. · The international journal of tuberculosis and lung disease : the official journal of the International Union against Tuberculosis and Lung Disease (2025)
GSH and NAC significantly improved lung function accelerated sputum conversion, and provided hepatoprotective effects.
The quality of the studies was assessed using the Cochrane Risk of Bias tool.</sec><sec><title>RESULTS</title>Eight controlled trials were included.
GSH, particularly in its liposomal form, enhanced immune responses by modulating cytokine levels and reducing oxidative stress.
Sadowski M et al. · Journal of cellular and molecular medicine (2024)
Huge benefit
← WorseNo effectBetter →
Likely real
A substantial decrease was observed in concentrations of IL-6 (p = 0.03; the standardized MD (SMD) was -1.71; 95% CI, -3.26, -0.16) and TBARS (p = 0.02; SMD was -1.03, 95% CI, -1.90, -0.15).
Furthermore, an elevation in GSH concentration was observed following supplementation.
However, we saw no significant effect of NAC on TNF-α, CK or GSSG concentrations.
14Mucus hypersecretion in airwaysSystematic ReviewCited 10×2024
Understanding the intimate mechanism of NAC versus MHS regulation may pave the way for more effective treatments targeting airway mucus dysfunction in COPD, ultimately improving patient outcomes and reducing morbidity and mortality associated with chronic mucus hypersecretion.
Rogliani P et al. · International journal of chronic obstructive pulmonary disease (2024)
This systematic review suggests that NAC acts as a mucolytic and a mucoregulator, directly inhibiting mucus secretion and goblet cell hyperplasia.
Given the critical role of MHS in COPD progression, exacerbations, and mortality, these findings highlight the potential of NAC as a targeted therapy for hypersecretion COPD phenotypes.
However, further studies are needed to confirm the results of this systematic review, even in human bronchial tissue, to provide translatable evidence in clinical settings.
15Schizophrenia symptom improvementMeta-AnalysisCited 76×n=220 · medium study2020
Evidence supports the notion that N-acetylcysteine may be a useful adjunct to standard treatment for the improvement of schizophrenia symptoms, as well as the cognitive domain of working memory.
Yolland CO et al. · The Australian and New Zealand journal of psychiatry (2020)
Positive and Negative Syndrome Scale negative and total scores were significantly improved in the N-acetylcysteine group after 24 weeks of treatment.
Evidence supports the notion that N-acetylcysteine may be a useful adjunct to standard treatment for the improvement of schizophrenia symptoms, as well as the cognitive domain of working memory.
Treatment effects were observed at the later time point (⩾24 weeks), suggesting that longer interventions are required for the success of N-acetylcysteine treatment.
Andrade C · The Journal of clinical psychiatry (2022)
Of these findings, reduction in psychopathology ratings, though statistically significant, appeared too small to be clinically meaningful.
Finally, a newly published, moderately large RCT of NAC (2,000 mg/d) in schizophrenia patients refractory to clozapine found that 1 year of treatment with NAC did not outperform placebo for any clinical, cognitive, or quality of life outcome.
The take-home message is that it is premature to recommend the use of NAC to treat schizophrenia for any target domain in routine clinical practice and that there does not appear to be a role for NAC for any indication in clozapine-refractory schizophrenia.
In conclusion, NAC orally daily produced a greater improvement in sperm concentration, ejaculate volume, sperm motility and normal morphology for idiopathic infertile men, whereas no significant influence in serum hormones, which required more high-quality RCTs with sufficient sample sizes and statistics to prove.
Zhou Z et al. · Andrologia (2021)
Finally, three articles including 431 infertile men were analysed.
However, the findings need further confirmation in well-designed randomized controlled trials to examine clinical outcomes such as live birth rate in more extended follow-up periods.
Devi N et al. · Journal of basic and clinical physiology and pharmacology (2020)