I know, I been incorporating it with my regular vitamin intake since the H-1 N-1 virus made its rounds around 2009-2011 as one of the members on FR suggested it as an alternate means instead of a ‘shot’. I think it was an MD, but certainly not gus dr. So far it has done a great job keeping any ‘bugs” away. But always remember to take NAC with at least two or three times the amount of vitamin C to get the most out of it and here is the reason.
N-Acetyl Cysteine Cautions
When taking N-acetyl cysteine it is recommended that two to three times as much vitamin C be taken at the same time. Failure to do so may result in more harm than good from taking this product because of the prolonged presence of the oxidized form of L-Cysteine. The vitamin C also helps keep the glutathione that is produced from the Cysteine in its reduced form so that it can continue acting as an antioxidant.
Stay healthy and well!
Some people have trouble with NAC. This might be why:
Supplementation with vitamin C and N-acetyl-cysteine increases oxidative stress in humans after an acute muscle injury induced by eccentric exercise
https://pubmed.ncbi.nlm.nih.gov/11557312/
Just a footnote, to the precaution that you mentioned.