I finally realised that I should read Broda Barnes, rather than dismissing him as a lunatic.

I ordered 'Hypothyroidism: The Unsuspected Illness', and read it through in one sitting the evening it arrived.

He doesn't have the idea of type 2 endocrine disorders, everything he claims is from his own observations, which I'd assumed were placebo-effect and confirmation bias.

His observations are a subset of my predictions. If you need supporting evidence, read his book, then look around.