Not at all.
I generally use two sources for my supplements. Life Extension and Swanson. Currently about 1/2 of my NAC is from each. While LE is good, Swanson is also and is competitively priced.
I take 600 mg each day. An NIH abstract on the use of NAC for coronavirus showed 1200 with onset of symptoms. If I feel out of sorts, like a cold coming on, I do to 1200. I can’t give you any personal “proof”. Only that research suggests it’s a good idea. I do it. Haven’t got deathly ill yet, which of course proves nothing LOL
OK, thanks for the information.