The ALA doesn't prevent from being excreted, it can attach to the heavy metal so it can be detoxed. It's more about your body's ability to excrete it through the normal detox process. If your body, mostly the liver, is inefficient at detoxing or if your body is already overloaded with "toxins" then adding more to your detox burden would not be desired. So it's better to go slow if adding in r-ALA to see how you do. Lower dosage and hold at that level for a week or so before upping the dosage.

If my memory serves me correctly, (and this is my simple way of understanding it), if you can't excrete it, the body will want to do something with it and deposit it again in the tissues. Adding fiber, and things like green drinks help guide the toxin/heavy metal out. I'll have to see if I can find info on it. It's been a long time since I looked into it and may not have kept the info. I was hoping it would be a good chelator for iron because at the time, John had iron overload and ALA is a know heavy metal chelator but not efficient enough to remove iron.

There's some who suggest not using ALA at all if you have amalgam fillings. We ignored that piece of info and John did fine on ALA.