Copper is used by the Thyroid to oxydize Iodide to IoDINE.
Most are better off taking Lugol's which is both, but if you are mercury toxic then taking large doses is not a good idea.
So you take a couple of drops of Lugol's and the rest P.IoDIDE. No idea about the pills but they are about the same as a bit over a drop of SSKI and I take about 4-6 drops of that.
And Yes the reason for Iodide in large amounts is because it controls critters....