I have severe allergies and asthma. I have been using NAC for over a decade for relief. It liquefies mucus by breaking it bonds in half. It liquefies snot throughout the body, not just the nasal passages. You might also look into pantothenic acid (B5) which stops the conversion of cholesterol into mucus and makes it convert into neurotransmitters. It will stop a runny nose in it's tracks. An increase in water consumption is of benefit as well when taking these chemicals.
RE: N-Acetyl Cysteine & Severe COVID-19
I have severe allergies and asthma. I have been using NAC for over a decade for relief. It liquefies mucus by breaking it bonds in half. It liquefies snot throughout the body, not just the nasal passages. You might also look into pantothenic acid (B5) which stops the conversion of cholesterol into mucus and makes it convert into neurotransmitters. It will stop a runny nose in it's tracks. An increase in water consumption is of benefit as well when taking these chemicals.