You are on the right track. 500mg is a standard over the counter dose for NAC. I have powder that I can adjust the dosage if I need to. But it is bitter. You can do the same thing with the pills - 2 grams would be 4 x 500mg/day. As far as companies that make supplements, I do not purchase Walmart's brand, most things at Costco, Kirkland, Puritans Pride, Swanson, etc. I will use those sites to buy certain manufacturers I like at a cheaper price. I like Life Extension, Jarrow Formulas, Nature's Way, Wild Harvest, and Carlson, among others. The best way to judge a product is to look at all the additional ingredients that are being added as fillers and carriers. The less the better. What is the source of the ingredients? Are mineral products bioavailable for the body to use or is it just ground up rocks from a gravel pit? Is it cheap industrial garbage? Pick up a bottle of Kirkland fish oil sold at Costco for example. Fish oil is way down on the list of ingredients and who knows where it comes from. I cannot believe the amount of crap that is contained in a product that people take thinking it will improve their health. Buyer beware for sure. I trust the companies I mentioned because I am confident in their manufacturing processes and their ingredient sourcing. But this is just my opinion based on my own research. If it is an herbal product, like pine needle oil, is it organically sourced? If is is fish oil, is it heat or hexane processed? Is it wild caught fish from clean water or farm raised? If the label says nothing, it is most likely farm raised GMO poisoned fish. In the world of supplements, I will admit it can be a minefield. Like anything else, it needs to be researched. Especially if you are going to put it in your body. Good luck.