N-acetyl cysteine (NAC) is the acetate derivative of the nonessential sulfur-containing amino acid cysteine. In an inhaled form, NAC is a prescription drug used for acute and chronic obstructive or inflammatory lung disorders including bronchitis, pneumonia, influenza, asthma, chronic obstructive pulmonary disease, and pulmonary fibrosis. Inhaled NAC thins mucus in the lungs, and normalizes its production so that mucus doesn't block the airway. Oral NAC is also very useful, and doesn't require a prescription.
Once you already have life-threatening respiratory distress, oral NAC isn't effective. However, oral NAC is very effectibe at preventing or lessening the severity of respiratory conditions and lung injury if supplements are taken prior to exposure to pathogens/toxins. We'll review some specific examples later. First, we need to understand how NAC protects us.
