Hi Isabella, I can only speak for myself. I had no problem going from 3% to 7%. Just know, however, that the 7% may cause you to cough, which it does me. I look at that as positive because what I am coughing up is mucus and that is the whole point of airway clearance. Besides that benefit, the 7% creates a very uncomfortable environment for that nasty MAC bacteria. Good luck and keep us posted on how it goes for you.