Hi adreno, I wondered the same thing some weeks ago when this was discussed before. NAC has a high cellular range - its goes almost everywhere in the body. Glutathione is good for most cells, particularly liver, but not all cells can absorb it or absorb it well. The fact that some cells absorb S-acetyl-glutathione does not mean all cells do. I am too busy to research this just now but its an interesting question. If someone can identify the exact molecular mechanism it uses to enter cells, and then find out if this is a common cellular mechanism, this might answer the question. If it uses a universal mechanism then it will be a good supplement. Bye, Alex