From the Guidelines
N-acetylcysteine (NAC) is not universally recommended as a supplement for everyone, but it may be beneficial for certain conditions, particularly for patients with moderate to severe COPD and a history of two or more exacerbations in the previous 2 years, as it has been shown to reduce the number of exacerbations 1. NAC is a modified form of the amino acid cysteine that serves as a precursor to glutathione, an important antioxidant in the body. It's primarily used medically as a treatment for acetaminophen overdose and as a mucolytic agent to break up thick mucus in conditions like cystic fibrosis and COPD. As a supplement, NAC is sometimes taken for its antioxidant properties, potential immune support, and possible benefits for respiratory conditions. Typical supplement dosages range from 600-1800 mg daily, often divided into 2-3 doses. However, NAC supplementation should be approached with caution as it can cause side effects including nausea, vomiting, and diarrhea. It may also interact with certain medications, particularly blood thinners. Some key points to consider when deciding whether to take NAC as a supplement include:
- The evidence for NAC's effectiveness for many popular uses is mixed, and its regulatory status has been somewhat controversial 1.
- NAC has been shown to be effective in reducing the rate of exacerbations in COPD, with a reduction in the rate of exacerbations associated with the use of NAC 1.
- The American College of Chest Physicians and Canadian Thoracic Society guideline suggests treatment with oral N-acetylcysteine to prevent acute exacerbations of COPD for patients with moderate to severe COPD and a history of two or more exacerbations in the previous 2 years 1. Before taking NAC as a supplement, it's advisable to consult with a healthcare provider to determine if it's appropriate for your specific health needs and circumstances.
From the FDA Drug Label
Acetylcysteine is the N-acetyl derivative of the naturally-occurring amino acid, L-cysteine. The compound is a white crystalline powder with the molecular formula C5H9NO3S, a molecular weight of 163. 2, and chemical name of N-acetyl-L-cysteine.
N-acetylcysteine is a derivative of the amino acid L-cysteine.
- It is not recommended as a supplement in the provided drug labels.
- The labels only discuss its use as an antidote for acetaminophen overdose and as a mucolytic agent 2, 2.
From the Research
What is N-Acetylcysteine
- N-Acetylcysteine (NAC) is a medicine used to treat various medical conditions, including Tylenol overdose, cystic fibrosis, and chronic obstructive lung disease 3.
- It has antioxidant and anti-inflammatory properties, which are used to treat diseases related to oxidative stress and inflammation 4.
- NAC can increase the intracellular concentration of glutathione, a crucial biothiol responsible for cellular redox imbalance, and reduce levels of tumor necrosis factor-alpha and interleukins by suppressing the activity of nuclear factor kappa B 4.
Recommended Use as a Supplement
- NAC may be useful as an adjuvant in treating various medical conditions, especially chronic diseases, such as polycystic ovary disease, male infertility, sleep apnea, and others 3.
- Supplementation with NAC may contribute to reducing morbidity and mortality in some chronic conditions, particularly as the population ages and levels of glutathione drop 3.
- However, the effectiveness of NAC in clinical trials addressing different pathological conditions is still limited, and more research is needed to fully understand its therapeutic potential 4.
Specific Conditions and Dosages
- For chronic bronchitis or COPD exacerbations, NAC treatment may be effective in preventing exacerbations, with a dose of ≥ 1200 mg per day recommended for patients with airway obstruction, and 600 mg per day for those without airway obstruction 5.
- A meta-analysis found that NAC reduced the frequency of chronic bronchitis exacerbations and improved symptoms, with a low dosage (< 1200 mg per day) and a duration of at least 3 months being effective 6.
- However, not all studies have found NAC to be effective, and some have reported no significant benefits or increased risk of adverse effects 7.