A: For most people I recommend starting at 200 micrograms. If you have thyroid antibodies, you should test them before taking it (but it's not a requirement, just a recommendation). Then you should wait three months before testing your thyroid antibodies again. Generally, we want to see about 25-50% reduction in thyroid antibodies after about three months. A dose of 200 micrograms of selenium does that for most people. If for some reason people's antibodies don't reduce as much, then I might suggest increasing the dose to 400 micrograms. But generally 200 is safe and the right dose for most people.