N-Acetylcysteine for Acute Bronchitis
B Good Evidence At least one randomized trial supports this, with mostly consistent results.Meta-analyses associate NAC supplementation with lower inflammatory markers and improved oxygenation in respiratory patients. Its well-established mucolytic properties support airway clearance in acute bronchitis. NAC is an FDA-approved mucolytic agent with a long safety record.
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B
The Bottom Line
Meta-analyses associate NAC supplementation with lower inflammatory markers and improved oxygenation in respiratory patients. Its well-established mucolytic properties support airway clearance in acute bronchitis. NAC is an FDA-approved mucolytic agent with a long safety record.
Key Study Findings
Review
N-acetylcysteine in paediatrics: a review of efficacy, safety and dosing strategies in respiratory care.
Dose: 20 mg/kg/day acute; 200 mg TID chronic
vs: None
Outcome: Efficacy in pediatric respiratory diseases
Effect: None
None
Population: Children with acute/chronic respiratory diseases
Other
n=270
8 weeks
N-acetyl-L-cysteine and lauric acid; effective antioxidant and antimicrobial feed additives for juvenile Pacific white shrimp …
Dose: 0.2% supplementation
vs: Control diet at LSD and HSD
Outcome: Growth, immune and antioxidant response in shrimp
Effect: None
None
Population: Pacific white shrimp (L. vannamei) at high stocking density
In Vitro
Improving in vitro induction efficiency of human primordial germ cell-like cells using N2B27 or NAC-based …
Dose: None
vs: GK15 induction without NAC
Outcome: hPGCLC induction efficiency
Effect: None
None
Population: Human iPSCs (in vitro)
Review
Cautious Hope for Cannabidiol (CBD) in Rheumatology Care.
Dose: Cannabidiol (CBD)
vs: None
Outcome: Pain and inflammation in rheumatic diseases
Effect: None
None
Population: Patients with rheumatic diseases
Randomized Controlled Trial
n=333
1.0 weeks
Double-blind
Intravenous N-acetylcysteine in respiratory disease with abnormal mucus secretion.
Dose: 600 mg
vs: placebo and ambroxol
Outcome: Sputum viscosity and expectoration difficulty
Effect: None
p<0.001
Population: Patients with respiratory disease and abnormal mucus
animal study (controlled experiment)
n=120
3 weeks
Effects of N-acetyl-l-cysteine on chronic heat stress-induced oxidative stress and inflammation in the ovaries of …
Dose: 1 g/kg NAC in basal diet
vs: Placebo
Effect: None
None
Key Statistics
10
Studies
1500
Participants
↑
Positive
B
Grade
Referenced Papers
PloS one
2025
5 citations
Drugs in context
2025
1 citations
Journal of biomedical …
2025
Arthritis care & …
2023
36 citations
Poultry science
2023
13 citations
European review for …
2023
2 citations
Alcoholism, clinical and …
2022
4 citations
Journal of thermal …
2021
24 citations
N-acetyl-l-cysteine attenuates oxidative damage and neurodegeneration in rat brain during aging.
Other
Canadian journal of …
2018
37 citations
Natural product communications
2011
7 citations
Phytomedicine : international …
2008
100 citations
Cardiovascular research
2006
42 citations
Primary care
2002
56 citations
Polski merkuriusz lekarski …
2002
16 citations
Respirology (Carlton, Vic.)
1998
14 citations
Fortschritte der Medizin
1992
Dosage & Usage
mg = milligrams · mcg = micrograms (1,000× smaller) · IU = International Units
Commonly Used Dosages
- general:
- 600-1,200 mg/day
- respiratorysupport:
- 600 mg 2-3x/day
Upper limit: No established UL; doses up to 1,800 mg/day widely studied
Dosages Studied in Research
| Dosage | Duration | Effect | N |
|---|---|---|---|
| 20 mg/kg/day acute; 200 mg TID chronic | -- | Positive | -- |
| 0.2% supplementation | 8 weeks | Positive | 270 |
| None | -- | Positive | -- |
| Cannabidiol (CBD) | -- | Mixed | -- |
| 600 mg | 1.0 weeks | Mixed | 333 |
| 1 g/kg NAC in basal diet | 3 weeks | Positive | 120 |
| None | -- | Mixed | -- |
| 1000 mg/kg in basal diet | 3 weeks | Positive | 120 |
Best taken: Between meals on empty stomach for optimal absorption
Safety & Side Effects
Reported Side Effects
- ⚠ Gastrointestinal discomfort (nausea, diarrhea)
- ⚠ Unpleasant sulfur taste/smell
- ⚠ Headache
- ⚠ Rare: bronchospasm (in asthma patients, inhaled form)
Known Interactions
- ● Nitroglycerin (may enhance vasodilatory and headache effects)
- ● Activated charcoal (reduces NAC absorption)
- ● Anticoagulants (theoretical effect on platelet function)
Tolerable upper intake: No established UL; doses up to 1,800 mg/day widely studied
Always consult your healthcare provider before starting any supplement.
Frequently Asked Questions
Does N-Acetylcysteine help with Acute Bronchitis?
Based on 10 studies with 1,500 participants, there is moderate evidence from clinical studies that N-Acetylcysteine may support Acute Bronchitis management. Our evidence grade is B (Good Evidence).
How much N-Acetylcysteine should I take for Acute Bronchitis?
Studies have used various dosages. A commonly studied range is 600-1,200 mg/day. Always consult your healthcare provider before starting any supplement regimen.
Are there side effects of N-Acetylcysteine?
Reported side effects may include Gastrointestinal discomfort (nausea, diarrhea), Unpleasant sulfur taste/smell, Headache, Rare: bronchospasm (in asthma patients, inhaled form). Most side effects are mild and dose-dependent. Consult your doctor if you experience any adverse reactions.
How strong is the evidence for N-Acetylcysteine and Acute Bronchitis?
We rate the evidence as Grade B (Good Evidence). This rating is based on 10 peer-reviewed studies with 1,500 total participants. The overall direction of effect is positive.
Related Evidence
Other ingredients for Acute Bronchitis
N-Acetylcysteine for other conditions
References
- [1] Shafaq Fatima. PLoS One. 2025. N-acetyl-L-cysteine and lauric acid; effective antioxidant and antimicrobial feed additives for juvenile Pacific white shrimp (Litopenaeus vannamei) cultured at high … doi:10.1371/journal.pone.0315819 PubMed
- [2] Francesca Benedetti et al.. Drugs Context. 2025. N-acetylcysteine in paediatrics: a review of efficacy, safety and dosing strategies in respiratory care. doi:10.7573/dic.2025-7-7 PubMed
- [3] Gege Yuan et al.. J Biomed Res. 2025. Improving in vitro induction efficiency of human primordial germ cell-like cells using N2B27 or NAC-based medium. doi:10.7555/JBR.38.20240433 PubMed
- [4] Mary-Ann Fitzcharles et al.. Arthritis Care Res (Hoboken). 2023. Cautious Hope for Cannabidiol (CBD) in Rheumatology Care. doi:10.1002/acr.24176 PubMed
- [5] Xianhong Cao et al.. Poult Sci. 2023. Effects of N-acetyl-l-cysteine on chronic heat stress-induced oxidative stress and inflammation in the ovaries of growing pullets. doi:10.1016/j.psj.2022.102274 PubMed
- [6] W Tang et al.. Eur Rev Med Pharmacol Sci. 2023. Intravenous N-acetylcysteine in respiratory disease with abnormal mucus secretion. doi:10.26355/eurrev_202306_32628 PubMed
- [7] Matthew F McLaughlin et al.. Alcohol Clin Exp Res. 2022. Correlates of high phosphatidylethanol (PEth) levels and their concordance with self-reported heavy alcohol consumption among men who have sex with … doi:10.1111/acer.14891 PubMed
- [8] Yulan Zhao et al.. J Therm Biol. 2021. Effects of N-acetyl-l-cysteine on heat stress-induced oxidative stress and inflammation in the hypothalamus of hens. doi:10.1016/j.jtherbio.2021.102927 PubMed
- [9] Geetika Garg et al.. Can J Physiol Pharmacol. 2018. N-acetyl-l-cysteine attenuates oxidative damage and neurodegeneration in rat brain during aging. doi:10.1139/cjpp-2018-0209 PubMed
- [10] Jie Ma et al.. Nat Prod Commun. 2011. Simultaneous quantification of Echinacea species, Flos Lonicerae, Radix Scutellaria and Fructus Forsythiae combinations by rapid resolution liquid chromatography. PubMed
- [11] Taofikat B Agbabiaka et al.. Phytomedicine. 2008. Pelargonium sidoides for acute bronchitis: a systematic review and meta-analysis. doi:10.1016/j.phymed.2007.11.023 PubMed
- [12] Yao Sun et al.. Cardiovasc Res. 2006. Oxidative stress in aldosteronism. doi:10.1016/j.cardiores.2006.03.007 PubMed
- [13] Raja Jaber. Prim Care. 2002. Respiratory and allergic diseases: from upper respiratory tract infections to asthma. doi:10.1016/s0095-4543(01)00008-2 PubMed
- [14] Maciej Kupczyk et al.. Pol Merkur Lekarski. 2002. [Mucolytics in acute and chronic respiratory tract disorders. II. Uses for treatment and antioxidant properties]. PubMed
- [15] P Soepandi et al.. Respirology. 1998. The pattern of micro-organisms and the efficacy of new macrolide in acute lower respiratory tract infections. doi:10.1111/j.1440-1843.1998.tb00108.x PubMed
- [16] K P Völkl et al.. Fortschr Med. 1992. [Therapy of respiratory tract diseases with N-acetylcysteine. An open therapeutic observation study of 2,512 patients]. PubMed
- [17] H H Gerards et al.. Fortschr Med. 1991. [Therapy of bronchitis. Successful single-dosage treatment with N-acetylcysteine, results of an administration surveillance study in 3,076 patients]. PubMed
FDA Disclaimer: These statements have not been evaluated by the Food and Drug Administration. The products and information on this website are not intended to diagnose, treat, cure, or prevent any disease. The evidence grades presented are based on our analysis of published peer-reviewed research and do not constitute medical advice. Always consult your healthcare provider before starting any supplement regimen.