I will say this - when I was very low in iodine and then started supplementing it, there was quite a dramatic reaction for sometime and I had to keep lessening the dose and at times taking a break. There was a sense of movement of toxins/metals (possibly some redistribution)which at times became intense - but I required that iodine and I believe I needed to supplement it. Replacing iodine, means of course "displacing" toxins and certain metals in those particular areas. Just as can happen with replacing anything mercury depletes or competes with.

Same can occur with selenium and other elements.

I don't think it hinders chelation - if anything it could be helpful. Both by the fact the body is getting more of what it requires and the fact a certain amount of metal may of course be displaced and mobilised to some extent. This may then be picked up by the chelating agent....

Though this is merely an opinion and an unqualified one at that. But certain replacing that which mercury depletes/blocks and competes with is I believe necessary, but can cause dramatic reactions. This is why it should be done carefully, slowly and gradually increased to tolerance. Even replacing antioxidants can be powerful enough. I had incredible reactions just by supplementing a high quality vitamin C powder containing bioflavanoids. I had to keep stopping and reducing the dose. That alone was enough to create a detox reaction!

But I do not believe they hurt chelation at all. I think chelation actually maybe helpful at the sametime, because it may pick up the extra metals that maybe mobilised after some have been displaced by replacing minerals/elements that compete with the metals.