Yep, I have to agree with Linda. Andy Cutler also suggests this and in fact, not only can straight glutathione not be overly beneficial, but can also cause issues in someone with mercury.

The best way to raise glutathione, is to take things like - selenium, milk thistle, NAC (but watch out for that one because it can move mercury), vitamin C can help too, Undenatured whey (excellent apparently).