NAC is a great supplement. It's awesome stuff to support healthy lungs. NAC is a known mucolytic. That is a fancy term meaning breaking up mucus. Now, research does show that NAC Levels of Reduced Glutathione (GSH) in Plasma and Lungs of Control and Download Table The Role of Glutathione in Oxidative StressRelated Neurodegenerative Calibrate Hydration Oxidants and Antioxidants Journal of The COPD Foundation Lung glutathione and oxidative stress: implications in cigarette smoke induced airway disease American Journal of Physiology Lung Cellular and Molecular Physiology American Physiological Society