There ae two ways to look at some vitamins. One way is to take them as a supplement in order to make up for what a person does not get via their regular diet. And the other is to accomplish something, smaller amounts just are unable to do. This holds true for buffered ascorbic acid, such as calcium ascorbate in a range of 3K to 5K mg (5K=5000mg) the same holds true for NAC which has a host of benefits. It would take to much space here to list all the benefits, but if you happen to have a computer go to the Dr. Mercola website and type in “What are the benefits of NAC”
You may or may not be able to get NAC in the vitamin section of perhaps Walmart etc. and if they happen to have it in pill form these small amounts of 500 mg or less and even if you take several are nothing more than a waste of money. As by mouth only a small percentage will be absorbed and in order to overcome the loss you will have to increase the intake to at least several thousand mg’s (milligrams) In other words 3K to 4K would be just about the right amount to do any good. This is the reason I have been buying most vitamins in bulk or powder form or many years, and if bought this way they are quite reasonable and available from sources such as Amazon as well as Purebulk. I hope that this will answer your question.