I'm hoping someone more knowledgable may be able to have some insight into this issue. I took NAC supplements a while back and had a bad reaction to the supplement. I had severe lightheadedness, headache, muscle tension, difficulty breathing, and anxiety. I assumed I was just a poor responder to glutathione support. Recently, I tried NAG based on the recommendation of Hip's thread about eliminating anxiety. I had the exact same reaction to the NAG supplement. This is just uneducated conjecture on my part, but since I have the homozygous ACAT mutation, could I have issues processing acetyl CoA which forms from the acetyl groups?