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 Taking too much of a supplement often causes side effects. This afternoon, my son wanted to go surfing. Forest fire smoke is settling in. He asked if he should take anything to The Pivotal Role of One Carbon Metabolism in Neoplastic Progression During the Aging Process Everyone says NAC can make glutathione. Wrong. Evidence against this is staring right at you. As you can see here, my wife's GCLC gene is genetically slower. Thus, she cannot convert Cysteine Glutathione 500 mg Plus 21st Century Vitamins 21st Century Vitamins