I don't take it every day but I often take it at pretty high doses (1200 to 1800 mg) due to an ear condition. The most adjacent condition is called Hyperacusis,

I don't take it every day but I often take it at pretty high doses (1200 to 1800 mg) due to an ear condition. The most adjacent condition is called Hyperacusis, which is the word I use most often in conversation, but in practice it differs in that, rather than simply having highly sensitive ears (i.e. sounds that don't harm others cause physical pain, but not permanent loss of function), it seems that my ears are very literally less able to withstand sound in general (i.e. sounds that don't harm others not only cause me physical pain, but also cause permanent hearing loss). I therefore have to be highly vigilant about the volume around me at all times. NAC has been shown to prevent hearing loss if taken very quickly after an acoustic trauma (up to 1 hour). I keep a bottle on me at all times. This is fuzzy personal science of course, but I can think of some instances of two comparable sounds in terms of volume/exposure time, where I took NAC after one and didn't after the other; after the former I was fine except for maybe a temporary spike in my tinnitus, and after the latter my hearing loss either started at a particular frequency or permanently worsened. I'm a former professional musician/audio engineer/etc (this condition put a stop to that), so my ability to judge this stuff is higher than average. No adverse reactions except for maybe a temporary increase in allergy symptoms. I have a ton of allergies (food and otherwise), and apparently NAC causes a large release of histamine. That said, I've also read reports that it's helpful for fighting allergies, so I guess always be wary of what you read when it comes to this stuff...