How will you know when someone has reached their optimal dose of the minerals i.e. enough for health but not too much?

I know by looking at thyroid markers and looking at the results of the hair test. I’m also telling my clients to take slightly above the daily recommended intake of these minerals so that we can slowly correct long standing deficiencies. So I never recommend too much. I never recommend massive dosages. It’s always close to what your body is expecting to receive each day and needs to receive each day. And I never recommend more than the "tolerable upper intake level" of these minerals. There is a maximum daily intake for minerals, and my recommendations are far below that.