I tried selenium for awhile before I was aware of the whole mercury issue. I had read that some thyroid issues can be resolved with selenium, magnesium, and chromium picolinate. I was taking 200 mcg in addition to my multivitamin.

I had two distinctly different side effects. First, my geographic tongue cleared up. Second, my skin which has been prone to bruising, began to bruise far worse, with distinctly yellow based bruises occuring every time I had the least little bump. When I stopped selenium, the geographic tongue came back and the bruising issue disappeared. Has anyone else had these sorts of symptoms?

Unfortunately, I noticed no improvement in my thyroid symptoms!

It looks like my dosage may have been too high for one who has mercury toxicity (and still has amalgams). I just had no clue at that time that mercury was an issue for me.