Jim,

I think you've essentially got the standard picture, except that TSH is thought to be the thing controlling T4/T3 production. There are those that say that it also controls T4->T3 conversion.

This paper: Homeostatic Control of the Thyroid–Pituitary Axis: Perspectives for Diagnosis and Treatment Rudolf Hoermann, John E. M. Midgley, Rolf Larisch and Johannes W. Dietrich

Suggests that it's all a bit more complicated than that though.

And I'd imagine that high TSH might make your thyroid swell, or what are goiters? Apparently goiters and cretinism used to be anticorrelated in areas where both were popular.

I'm certainly not suggesting that anyone with CFS should start snorting pig thyroid! I think that's just sticking a screwdriver in a complicated control mechanism. You might well provoke a response.....

I am saying that CFS/FMS/hypothyroidism look far too similar for it to be a coincidence, two different diseases with the exact same symptoms apart from TSH, and that CFS may well be related to some aspect of disturbed metabolic rate-control. And that I don't think that the normal TSH of CFS sufferers is enough to prove that CFS is something else entirely.

And obviously, I wonder if pig-thyroid might not be a bad screwdriver to stick in. And I'm puzzled that no-one's tried it in a PCRT. There are occasional papers where someone's given T4 alone to tired people (well, I've read one). That doesn't seem to work, or at least if it did work on a couple of them it wasn't enough of them to make a statistically significant difference to the group as a whole.

And there are other papers where people have given T4/T3 mixes to hypothyroid cases. There was a famous one where it measurably worked, and lots of attempts to replicate it with slightly different cocktails that didn't. And of course, scientific statistics being what it is that's gone down as 1 vote for, 7 votes against, so the initial interest has died down. I think it's pretty solid that some patients prefer various T4/T3 mixes, it's just that no-one cares.

I think actually just trying random things is doomed to fail, and what's necessary is to work out what's going on and what's likely to work.

My money would be on T4 plus a tiny bit of T3 being the ideal solution for a large subclass of CFS sufferers whose metabolism is running slow. But I have no clue.