For me, adding NAC to my management plan had an immediate and dramatic effect. I was unable to produce sputum, but that changed drastically once I started taking NAC. Interestingly, I recently cut down to one dose per day in the morning because I read in this forum that it was causing sleeplessness for some, so I thought maybe that was the culprit for my own nocturna tossing and turning. (I am sleeping better as a result.) I again noticed the change - this time to less production - so much so that I am thinking about adding the second dose back with plans to take it earlier in the afternoon. It’s a question on my list for when I go to National Jewish Health in April!