Would most people benefit from taking an iodine supplement to support their thyroid function, and perhaps other needs, even if they use iodized salt in cooking? I’ve heard the latter is ineffective.

It is true that iodized salt is not a total answer in supplying needed iodine. Having an adequate supply of iodine is essential for normal physiologic functioning. When there is a deficit, there will be consequences as well. So it makes sense to safeguard well-being through use, if only occasionally, of an iodine supplement, taking precautions to look carefully at the form it is in to ensure what one is suggesting will be bioavailable. And we leave that to you to do the research.