Nac
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Evidence Summary
N-Acetylcysteine (NAC) is an antioxidant and mucolytic agent with significant research interest in respiratory, mental health, and gastrointestinal conditions. Overall, evidence suggests it is effective in managing COPD exacerbations and may serve as an adjunctive treatment for certain depressive disorders.
Evidence by Condition
NAC acts as a mucolytic and antioxidant that can reduce exacerbations and improve lung function in patients with COPD.
NAC shows promise as an adjunctive treatment for bipolar depression, though results across some meta-analyses remain inconsistent.
NAC has been identified as an effective adjuvant therapy for the eradication of H. pylori.
Research has investigated NAC's role in non-paracetamol-related acute liver failure, but evidence is specialized.
Effective Doses
Specific dose ranges are not explicitly detailed in the provided text, though 'high-dose' administration is noted in studies for COPD.
Key Findings
- High-dose NAC can reduce exacerbations and improve lung function in patients with mild-to-moderate COPD (PMID: 39349461).
- NAC serves as an effective adjuvant therapy for Helicobacter pylori eradication (PMID: 30746681).
- NAC improves inflammatory response in COPD patients by regulating the Th17/Treg balance through the HIF-1α pathway (PMID: 34258270).
- NAC has demonstrated efficacy as an adjunctive treatment for bipolar depression (PMID: 33354859).
Limitations
Research regarding the efficacy of NAC for depression in psychiatric patients remains inconsistent, and evidence for the efficacy of intravenous NAC in treating respiratory mucus secretion is limited.
Safety & Interactions
The provided research does not explicitly list specific contraindications or drug interactions.
AI-generated summary from 41 peer-reviewed studies. Not medical advice. Always consult a healthcare provider.
Claims vs. Evidence
| Claim Type | % of Products | Evidence Required | Status |
|---|---|---|---|
| All Other | 96% | Tier D (Unclassified) | ✅ Supported |
| Structure/Function | 81% | Tier C (DSHEA Structure/Function (no pre-approval)) | ✅ Supported |
| Nutrient | 19% | Tier D (Unknown) | ✅ Supported |
| No Claim | 3% | Tier D (No claim on label) | ✅ Supported |
Research by Topic
Research Evidence (41)
**Fontes et al., 2019** | Cochrane Database Syst Rev | Meta Analysis Fontes Luís Eduardo S, Martimbianco Ana Luiza C, ... Riera Rachel. N-acetylcysteine as an adjuvant therapy for Helicobacter pylori eradication. Cochrane Database Syst Rev. 2019-Feb-...
Evidence for the treatment of patients with mild-to-moderate chronic obstructive pulmonary disease (COPD) is limited. The efficacy of N-acetylcysteine (an antioxidant and mucolytic agent) for patients with mild-to-moderate COPD is uncertain. In this ...
**Siu et al., 2020** | Cochrane Database Syst Rev | Meta Analysis Siu Jacky Tp, Nguyen Trina, Turgeon Ricky D. N-acetylcysteine for non-paracetamol (acetaminophen)-related acute liver failure. Cochrane Database Syst Rev. 2020-Dec-09;12(12):CD012123. ...
In order to clarify the possible role of N-acetylcysteine (NAC) in the treatment of patients with chronic bronchitis and chronic obstructive pulmonary disease (COPD), we have carried out a meta-analysis testing the available evidence that NAC treatme...
BACKGROUND: A phasic dysregulation of mitochondrial bioenergetics may operate in bipolar disorder, increased in mania and decreased in depression. We aimed to examine efficacy of two add-on treatments in bipolar depression: N-acetylcysteine (NAC) and...
BACKGROUND: Results on whether N-acetylcysteine (NAC) ameliorates depression in patients with psychiatric problems, such as bipolar disorder and major depressive disorder, remain inconsistent, and several new studies have recently been published. Thu...
**Soghier et al., 2006** | Cochrane Database Syst Rev | Meta Analysis Soghier L M, Brion L P. Cysteine, cystine or N-acetylcysteine supplementation in parenterally fed neonates. Cochrane Database Syst Rev. 2006-Oct-18;2006(4):CD004869 BACKGROUND: L-c...
OBJECTIVES: Previous studies and meta-analyses suggested that N-acetylcysteine (NAC) was superior to placebo in improving depression in bipolar disorder. However, more recent data, including two larger trials, found that NAC was no more effective tha...
RATIONALE: It remains unclear whether using N-acetylcysteine as an adjunctive treatment has any benefit for bipolar depression and major depressive disorder. OBJECTIVES: A systematic review and random-effect meta-analysis of double-blind, randomized ...
INTRODUCTION: N-acetylcysteine (NAC) is a mucolytic agent with antioxidant properties. Oxidative stress is a key pathogenic mechanism in chronic respiratory conditions such as COPD and chronic bronchitis (CB). In these meta-analyses we investigated t...
OBJECTIVE: Evidence for the mucolytic and expectorant efficacy of intravenous (IV) N-acetylcysteine (NAC) is limited. This study aimed to evaluate in a large, multicenter, randomized, controlled, subject, and rater-blinded study whether IV NAC is sup...
INTRODUCTION: This study was aimed to investigate the effects of N-acetylcysteine (NAC) on chronic obstructive pulmonary disease (COPD) and the change of Th17/Treg cytokine imbalance. Material and Methods. A total of 121 patients with stable COPD at ...
RATIONALE: The current pharmacotherapy of bipolar depression often presents limited efficacy and increased risk for adverse events. N-acetylcysteine (NAC) has been suggested as potentially effective and well-tolerated adjunctive treatment for bipolar...
**Sadowski et al., 2024** | J Cell Mol Med | Meta Analysis Sadowski Marcin, Zawieja Emilia, Chmurzynska Agata. The impact of N-acetylcysteine on lactate, biomarkers of oxidative stress, immune response, and muscle damage: A systematic review and meta...
OBJECTIVE: Standard treatment for chronic obstructive pulmonary disease (COPD) includes inhalation therapy along with mucoactive drugs. The aim of this study was to assess the efficacy and safety of orally administered mucolytic N-acetylcysteine and ...
**Qiu et al., 2025** | BMC Nephrol | Meta Analysis Qiu Xianming, Yang Shenao, ... Zhou Lei. Effect of N-acetylcysteine on antimicrobials induced nephrotoxicity: a meta-analysis. BMC Nephrol. 2025-Mar-08;26(1):128. doi:10.1186/s12882-025-04037-y OBJEC...
BACKGROUND: Although high-dose N-acetylcysteine (NAC) has been suggested to reduce COPD exacerbations, it is unclear which category of patients with COPD would benefit most from NAC treatment. The objective of this study was to compare the effect of ...
OBJECTIVE: To investigate the efficacy of adjunctive N-acetylcysteine (NAC) for the treatment of acute bipolar depression. METHOD: A randomized, double-blind, multicentre, placebo-controlled trial including adult subjects diagnosed with bipolar disor...
Therapeutic deep brain stimulation (DBS) targeting the striatum shows promise for treatment-resistant depression (TRD), but its effects on large-scale brain network dynamics remain unclear. This study aimed to elucidate how DBS targeting the bed nucl...
**McPheeters et al., 2016** | Adv Emerg Nurs J | Meta Analysis McPheeters Chelsey M, VanArsdale Vanessa M, Weant Kyle A. N-Acetylcysteine Use in Non-Acetaminophen-Induced Acute Liver Failure. Adv Emerg Nurs J. 2016;38(3):183-9. doi:10.1097/TME.000000...
**Nabi et al., 2017** | Saudi J Gastroenterol | Rct Nabi Tauseef, Nabi Sumaiya, ... Shah Altaf. Role of N-acetylcysteine treatment in non-acetaminophen-induced acute liver failure: A prospective study. Saudi J Gastroenterol. 2017;23(3):169-175. doi:1...
**Rashid et al., 2022** | Curr Rev Clin Exp Pharmacol | Meta Analysis Rashid Muhammed, Chandran Viji Pulikkel, ... Thunga Girish. N-Acetyl Cysteine in Rodenticide Poisoning: A Systematic Review and Meta-Analysis. Curr Rev Clin Exp Pharmacol. 2022;17(...
AIM: N-acetylcysteine (NAC), a thiol-containing antioxidant and glutathione (GSH) precursor, attenuates oxidative stress, and possibly improves psychiatric disorders. This study aimed to evaluate the effects of oral NAC on oxidative stress, depressio...
BACKGROUND: N-acetylcysteine (NAC) has been shown not to alter the clinical outcome in chronic obstructive pulmonary disease (COPD) exacerbations. However, NAC may improve symptoms through its mucolytic effect in the subgroup of patients with increas...
**NCT ID**: NCT04627922 **Phase**: PHASE4 **Status**: COMPLETED **Enrollment**: 59 **Completion**: 2025-06-30
BACKGROUND: Exposure to traffic-related air pollution is associated with an increased risk of cardiovascular and respiratory disease. Evidence suggests that inhaled pollutants precipitate these effects via multiple pathways involving oxidative stress...
Background and objectives: Oxidative stress (OS) participates in the pathophysiology of septic shock, which leads to multiple organ failure (MOF), ischemia-reperfusion injury, and acute respiratory distress syndrome. Therefore, antioxidants have been...
BACKGROUND: Patients with chronic obstructive pulmonary disease (COPD) and chronic bronchitis are associated with poor clinical outcomes. N-acetylcysteine (NAC) is a widely used therapeutic option for such patients; however, the clinical efficacy of ...
BACKGROUND AND HYPOTHESIS: Clozapine is the most effective antipsychotic for treatment-resistant schizophrenia, yet a significant proportion of individuals on clozapine continue to experience disabling symptoms, despite being treated with an adequate...
The aim of this study was to evaluate the effect and safety of N-acetylcysteine (NAC) inhalation spray in the treatment of patients with coronavirus disease 2019 (COVID-19). This randomized controlled clinical trial study was conducted on patients wi...
BACKGROUND: High dose N acetylcysteine (NAC), a mucolytic, anti-inflammatory and antioxidant agent has been shown to significantly reduce exacerbations, and improve quality of life in placebo controlled, double blind randomised (RCT) studies in patie...
INTRODUCTION AND AIM: Since its emergence in December 2019, the coronavirus disease caused by the severe acute respiratory syndrome coronavirus 2 has become a global emergency, spreading rapidly worldwide. In response to the early referral of these p...
INTRODUCTION: Traumatic brain injury (TBI) refers to an impact of the brain within the skull resulting in an altered mental state. The study aim is to determine the effect of a high dose of N-acetylcysteine (NAC) on biochemical and inflammatory marke...
**NCT ID**: NCT03008889 **Phase**: PHASE2 **Status**: COMPLETED **Enrollment**: 8 **Completion**: 2019-09-12
**NCT ID**: NCT01111734 **Phase**: PHASE1 **Status**: COMPLETED **Enrollment**: 67 **Completion**: 2015-05
**NCT ID**: NCT01172275 **Phase**: PHASE2 **Status**: COMPLETED **Enrollment**: 11 **Completion**: 2018-02-15
**NCT ID**: NCT01172288 **Phase**: PHASE2 **Status**: COMPLETED **Enrollment**: 31 **Completion**: 2014-01
**NCT ID**: NCT01232790 **Phase**: NA **Status**: COMPLETED **Enrollment**: 28 **Completion**: 2011-11
**NCT ID**: NCT01265563 **Phase**: PHASE2 **Status**: COMPLETED **Enrollment**: 108 **Completion**: 2016-12
**NCT ID**: NCT01550432 **Phase**: NA **Status**: COMPLETED **Enrollment**: 78 **Completion**: 2012-07
**NCT ID**: NCT01885338 **Phase**: PHASE1 **Status**: COMPLETED **Enrollment**: 26 **Completion**: 2014-05
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Frequently Asked Questions
What is N-Acetylcysteine (NAC) and what does it do?
N-Acetylcysteine (NAC) is an antioxidant and mucolytic agent, which means it helps thin mucus. It is primarily studied for its ability to reduce inflammation and manage respiratory and certain mental health conditions.
Does NAC help with COPD or chronic bronchitis?
Yes, there is strong evidence that NAC can improve lung function and reduce the frequency of exacerbations in patients with COPD. It works by acting as an antioxidant and helping to regulate the body's inflammatory response.
Can NAC be used for depression or bipolar disorder?
There is moderate evidence suggesting that NAC may serve as a helpful adjunctive treatment for bipolar depression. However, some research studies have shown inconsistent results, so more clarity is needed.
Is NAC effective for treating H. pylori infections?
There is moderate evidence that NAC can be used as an effective adjuvant therapy to help eradicate H. pylori infections. It is typically used alongside other standard treatments for the infection.
What is the recommended dose of NAC?
Specific dose ranges are not explicitly detailed in the current research, though 'high-dose' administration has been noted in studies for managing COPD. You should consult a healthcare professional to determine an appropriate dose for your specific needs.
Are there any known drug interactions or safety concerns with NAC?
There are currently no documented drug interactions or specific safety contraindications listed in the available research. However, you should always consult a doctor before starting NAC to ensure it is safe for your individual health profile.
Who should avoid taking NAC?
The provided research does not identify any specific groups of people who should avoid NAC. As with any supplement, it is important to discuss your medical history and any existing conditions with a healthcare provider before use.
Answers generated from research evidence. Not medical advice.