Thyroid UK
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Has anyone else been over active without knowing then years later become under active?

I was diagnosed as having an underactive thyroid in March with a TSH >100 which I am currently being treated with 150mcg levothyroxine. I got a print out of all my previous blood tests I've had done over the years and back in 2005 it shows that I was just overactive with a TSH 0.37 (0.4-5.0) has anyone else had this or knows what it means? (If anything)

6 Replies

It is not uncommon for people with Hashimoto's to have had times where TSH is a touch on the low side. Indeed, variations can occur in people over the years, have a look at this table:

Table 1. Presentations of Hashimoto’s Thyroiditis

Euthyroidism and goiter

Subclinical hypothyroidism and goiter

Primary thyroid failure


Adolescent goiter

Painless thyroiditis or silent thyroiditis

Postpartum painless thyrotoxicosis

Alternating hypo- and hyperthyroidism

Have you been tested for Thyroid Peroxidase antibodies or Thyroglobulin antibodies?



No Rod, there is nothing on my printout of either of those being tested. Do you think I should ask for them to be done on my next bloods? x


Well unless you have something else going on, it does seem likely that you have autoimmune thyroid disease in the form of Hashimoto's - and a positive TPO antibody test is a strong indicator of that. Around 80% of hypothyroid people in the USA and the UK seem to have Hashimoto's - so it is pretty common. Knowing it can sometimes help to explain some of the oddities.



Hi personally l don't think that you were overactive at that tsh of 0.37. A lot of healthy people have a tsh of under 1, and different labs have different ranges. Did you feel hyper back then? You may have been hyper but maybe that was your "normal" tsh.

Jo xx


Hi Jo, yes I went to the doctor with exhaustion and was put on anti depressants, I also lost 5stone that year but have since piled it all back on!! x


I have just been diagnosed with Graves Disease have had tsh readings o.94_1.2.I have had severe symptons of hyper,lost 5 kgs now waiting on more tests results Have started on gluten free diet& low iodine.I was only taking 50mcgs Eutroxsig.I know now Tsh tests are unreliable as it has taken 5 mths of hell for a holistic Gp to listen to me.meignore Tsh


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