Hi wsbme74. My pulmolnary doc would not prescribe me 7% rather than 3% even with me asking on 2-3 separate visits. His comment is, "The studies does not support that it works better." Because of the amount of feedback from all the folks on this forum I purchased 7% from Amazon. I have been using half 3% and half 7% with AM nebbing and full 7% in the evening. Prior to getting the 7% I was not coughing up anything but feeling OK. When I began using 7% I occasionally (about once a week) cough up dark brown sticky stuff. That tells me that I've still got the Pseudomonas in there and the 7% is helping bring it out. I've only used Mucinex off and on but I think now I need to use it more regularly. I'm convinced it helps.