You can have both, in general toxic stuff aka oxydized comes out first with NAC, then later as the cells recover and drop unbound copper which they held onto into the blood. While the cell had unbound copper it could not produce Lysine as a byproduct and left you with a bad potassium cell balance. The adrenals are then supposed to bind all that copper to an amino acid and fail leaving you with a ton of weird issues.
MSM binds to unbound copper while NAC binds to oxydized copper...unless money is an issue supplement both but 300mg NAC is enough while MSM should be 1500-2000mg several times a day...