NAC reduces levels of proinflammatory cytokines and oxidative stress.[1][2] Because NAC increases glutathione levels in the body, which are rapidly depleted by stress, disease, or drug toxicity, it has applications in clinical settings, in addition to general health and wellness. NAC has been used for the treatment of cystic fibrosis (due to its mucolytic properties),[3] acetaminophen (paracetamol) toxicity,[4] and chronic obstructive pulmonary disease (COPD).
In COPD, NAC may improve lung function and speed the rate of symptom improvement when used during a symptom flare up (an exacerbation).[5] Long-term use (more than 3–6 months) may improve symptoms of chronic bronchitis and reduce the risk of COPD exacerbations,[6][7][8] although the latter effect has not been found consistently.[9] Additionally, NAC does not seem to prevent declining lung function when used over a long period of time.[9]