NAC is a sulfur bearing amino acid. as such it holds a weak pull for heavy metals such as lead, mercury, etc.
all of this information is in andrew cutler's books. please read them. more than half of newport's information comes straight from cutler's books.
i hope that everyone here who is struggling and has not gotten to the root of their problem will at least read the cutler material. it doesn't mean you have to follow through, but i'm sure some people will find a few doors opening to a previously stuck situation.
the subject is a little bit too complex for little blurbs here and there, so you really have to absorb the material yourself or hire a cutler-friendly practitioner to think for you.
the over simplified and incomplete version is that any dietary sulfur, including amino acids such as NAC, garlic, broccoli, eggs, onions, etc have the chance to stir up your metals without binding to them. it doesn't mean that you will necessarily get worse from redistribution, but it is something to be aware of. some people will get worse, some not, and some people will feel a whole lot better depending on 1000 other variables of their particular chemistry
the chelators he works with are dmsa, dmps, alpha lipoic acid, and perhaps edta??? all form tight bonds with certain metals which make them chelators in that they grab onto the metal for a certain amount of time. his protocol is fairly involved but this is the very basic starting point. there are no rules set in stone, and he clearly states this, you have to partially just go by how you feel.
there are people in the cutler chelation forum who are willing to help out.
there are also generic ways to deal with heavy metal poisoning such as Bentonite baths, sauna, oxidizing the metals with ozone, klinghardt's new silica protocol, and the ion foot baths.
the subject of taking glutathione is covered in the cutler book. he doesn't recommend taking glutathione as it gets destroyed in the gut. taking the individual precursors though... glutamine, glycine, and cysteine (sp?) are recommended. there are some foods such as Watermelon and avocados that some people report anecdotally as providing useable dietary glutathione. if you are in a severe state of metal toxicity then oral glutathione alone, imo will not really dent the problem. last i read of cutler, the precursors were just an adjunct to his program and the heavy lifting was done by the chelators.
another source of glutathione precursors is immunocal.
just popping pills alone is not enough, you have to make sure that your liver and kidneys are in proper shape to handle the detox, and the whole thing can be a big mess, or at least extremely complicated.
i know of one person who did aggressive sauna for a few years plus immunocal and cured himself.
in my opinion the cutler material is excellent for at least establishing a reasonable hypothesis for the root cause of the problem. his actual chelation protocols are a different issue and a bit controversial as there are other alternatives to getting the stuff out of you.