My pulmonologist also prescribed 3% for me and when I asked about 7% after seeing it talked about on Mayo site, he said he had no problem prescribing 7%. He also said it is harder to get since the pandemic. My pulmonologist here in FL is a very nice man but like most he doesn’t know a lot about MAC. Understandable because it is rare but everyone I have talked to in FL and CO say MAC is being diagnosed more all the time. Saline is not a medication and some have reported it is not covered by Medicare or insurance because it is not a medication. Both 3% and 7% Saline are readily available on Amazon.com from Base Labs. I have found that 7% definitely brings up more mucous. I have no idea why there is a hold up getting saline in pharmacies unless it is due to it not being a medication. My daughter has been an RN for 32+ years. She is who let me know that I didn’t need a prescription and it was readily available on Amazon.