If TSH doesn’t matter, why does it have to be 1 or lower?

[Flecmac]

I understand that TSH is a patuitary hormone not a thyroid one and that it doesn’t matter what it is with Hashimoto’s. Could anyone explain why then does it have to be 1 or lower? Thanks

[Clutter]

McDermott,

TSH does matter. When T4 and T3 are low the pituitary issues TSH to stimulate the thyroid gland to produce more hormone. When sufficient T4 and T3 are circulating TSH is shut off and TSH level drops.

If TSH is the only thing tested most people will be adequately dose when TSH is between 0.2 - 1.0.

[radd]

mcdermott,

For many the TSH does matter .... .

but for others medicating thyroid hormone replacement "well-being" may only be achieved with a suppressed TSH level .... which ignorant doctors take to mean there is too much thyroid hormone in the blood stream.

T4 levels (& T3 if tested) are expected to raise to an acceptable "well being" level when medicating thyroid hormone replacement but for some people thyroid hormones will not raise enough (to reach well-being) until TSH reaches a certain low (or been suppressed.)

However, a suppressed TSH is not a guarantee of well-being, as can not accurately gauge whether the exogenous thyroid hormone dosage is sufficient, excessive or adequate, unless consideration is given to the tissue effects of thyroid hormone replacement and assessing basal temperature and/or pulse rate, blood serum T3/T4 levels and most importantly symptoms ... how we feel.

There can occur a down regulation of the pituitary- thyroid connection after years of suppressing TSH by medicating thyroid hormone replacement so the TSH feedback loop is not functioning properly ........, or maybe it never functioned properly in the first place ! ? ! ? ... or else how could TSH levels be suppressed when the T4 and T3 thyroid hormone levels are not above range ? ? .... and the TSH in people with a dysfunctional hypothalamus or pituitary gland will never accurately reflect their actual thyroid levels.

It is also possible for a small dose of thyroid hormone replacement to raise TSH as the pituitary senses new hormone and reduces TSH production.

[greygoose]

I don't think anyone ever said it doesn't matter when you have Hashi's. What is usually said is that when you are on thyroid hormone replacement, it doesn't matter how low it goes, as long as the FT3 is in range. But, if the TSH goes high, then it means that you are under-medicated.

The reason it needs to be one or below is because if it's higher than that, then the FT4/3 will be too low. But, it's low T3 that causes symptoms, not the TSH itself.

[Flecmac]

Many thanks for your replies, I need to get things right in my head before I see endo next week. Much appreciated.

[Angel_of_the_North]

It doesn't matter in isolation, but needs to be considered along with Free t3 and free t4. The Dr Toft Pulse article says that most people will find that symptoms go when TSH is under 1 and free T4 is in the top quarter of the range, but that some people will need free t4 slightly over range and TSH under range in order to make enough T3 (his new article suggest giving T3 instead). But we have no way of knowing whether the hypothalamus and pituitary are working correctly so just going on TSH and ignoring the actual thyroid hormones is what keeps many people ill. Some of the research suggests that TSH rarely returns to the levels seen in healthy people when we take exogenous hormones (unless frees are far too low for health).

[guysgrams]

What if medicating with T3 only? The last time (10/2017) I had my FT4 tested it was .1 (.8-1.7).

[humanbean in reply to guysgrams]

When taking T3 only, Free T4 is likely to be zero or extremely low i.e. a long way under range.

Under those circumstances you would pay attention to Free T3 level. Ideally for most people I think it would be in the upper half of the range, possibly even high in range. A few people may even need it to be over the range by a small amount.

I'm on T3 only. The last time I tested myself my Free T3 was over the range. I lowered my dose and the persistent fatigue I had reduced quite a lot. Having too much T3 can cause fatigue, just like having too little.

[Junep in reply to humanbean]

Hi , I was very interested to read your comment about too much t3 causing fatigue as well as too little , as I think this has just happened with me .

I went onto t3 only after poor conversion ( did a urine test ) and all was well until a couple of weeks ago when I felt the symptoms return , so I started to take NDT again and have felt much better . However I'm wondering whether to add a little t3 in again ?

[humanbean in reply to Junep]

Without test results it is impossible for anyone to say, sorry.

[Junep in reply to humanbean]

Haven't had any tests for a while now , but t3 was over last time around 8 which was too high , but have lowered the dose since then quite a bit , but think primarily we need to listen to our bodies .

[Flecmac]

I’ve never had FT3 and FT4 levels tested, how important are they?