I decided to write a review today after pulling out a half used bottle of this NAC for an unusual reason. I have been taking bee propolis and yesterday had a headache so too tylenol. I hardly ever take it but because i take vitamin C and other viamins and herbs that could thin blood, I didn't want to take aspirin or anything like that on top of the natural products. That was a a mistake. I became very sick feeling and for hours couldn't figure out what was going on. I ended up reading just by chance something about bee propolis on selfhacked and saw that it mentioned it has the same enzyme blocking ability as grapefruit. So if you take it with a drug that works through the liver such as tylenol, it blocks the liver from being able to metabolise the drug, and the high levels of it are in your system. Everyone knows the dangers of tylenol poisoning. I just didn't think I had any reason to worry since I only took 2. But I was suddenly certain that this was the cause of my feeling so sick. So I went and dug out the NAC i knew I still had in a cabinet and took some with some vitamin C because vitamin C is synergistic with NAC. Anyways it healed me overnight. But the thing that I noticed right away was actually the same thing I noticed when I first bought the bottle of NAC. It's lack of smell. The bottle is a year old and it smells just slightly a bit like vinegar but not strong. Before finding this brand I had bought about 6 different brands of it but always had a rotten egg, overpowering stench from hydrogen sulfide from the sulfur in the NAC oxidising. A lot of people are going by an urban myth that the stinkier it is the better it works. This isn't true. The smelly ones have gone off. You wouldn't drink from a rusted coke can so why swallow an old oxidised capsule of sulfur? Not only is that gross, but the smelly ones gave me nausea and Heartburn every time, but these ones don't. So either this brand is just amazing, or I got lucky with my particular bottle and it was kept cool and didn't begin oxidising. A slight little vinegar smell is okay but a stench of rotten eggs isn't. I've decided to continue taking these each day til the rest of the bottle is used up and then I"ll order another and hope to get the same fresh results. If not I"ll update and we can then assume that the conditions that it was kept in does effect the quality