Andy states that if you are not mercury toxic, taking chelators should produce no effect, positive or negative. In fact, he even recommends that if you don't have amalgams (such in the case of children) that doing a couple rounds of chelation is a good way to confirm diagnosis of mercury toxicity. For adults, its harder because you can't do this with amalgams in, and once you get your amalgams out, you will have some exposure, so its harder to use such a theraputic trial to confirm things.