My dr mentioned this to me and I thought I'd mention it here. I take way more thyroid medication than the typical thyroid patient and I don't feel well until I"m at the highest point in the normal range. Mark Starr has a hypothesis that there is thyroid resistance to thyroid hormones. Some subclinical hypthyroidism could be resistance.

She also mentioned that eating wheat could keep me from metabolizing thyroid hormone and although my B12 is right in the middle of normal she suggested I supplement since its required for thyroid hormone as well.

You can google on youtube if interested.