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Thyroid UK
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Cause of Hypothyroidism


I'm new to this but relieved to read the stories of so many.

I'm hypothyroid and was diagnosed about 3 years ago when I was 23. My mum has hypothyroidism (autoimmune) and my sister has subclinical hypothyroidism but due to family history is being treated.

Since being diagnosed I have asked all of my GPs why I have hypothyroidism. Multiple tests from multiple GPs surgeries as I've moved about have told me I don't have autoimmune hypothyroidism despite my mum having it. I haven't pushed too hard on getting an answer to why I have developed it, the only answer I've had is 'sometimes these things happen'.

Do I need to push on the reasons behind why I have developed hypothyroidism in my early twenties? Will knowing why help my treatment or is it just something I have to accept sometimes happens?

For info I'm currently on 100mg on weekdays and 125mg on weekends. Last test a few months ago

TSH 1.06

FT4 16.1


5 Replies

To find out whether you have autoimmune thyroid disease or not you need to have TPO Thyroid Peroxidase antibodies and TgAb Thyroglobulin antibodies tested. Get a copy of your blood tests, if living in England you can register for these online via your GP surgery. You will then be able to see if thyroid antibodies tests have been done and if not then ask for it.

If your GP questions why you want the tests then explain that having a definitive answer will help you manage your condition better as many, many people on this forum find going gluten free helps to reduce antibodies. Also, as blood test results can fluctuate with thyroid antibodies, it's important to understand what is happening in order to manage your condition.

90% of hypothyroidism in the UK is caused by Hashimotos so worth finding out.


It doesn't matter why you developed hypothyroidism. It's possible you had autoimmune and the antibodies have gone, they usually do in time. As long as your medication is making you better the original cause doesn't matter. Worrying about it will just stop you enjoying life.


Many if not all of the women on my mothers side have developed it. Some also get lymphoma of the thyroid. Guys were vague about why I developed it but there must be a hereditary component involved.

23 is young to get it and was the age I was on the onset of my first symptoms, strangely. I think there may be a lot more genetic discovery to be done yet that could shed more light on why we get this disorder. The antibody tests mentioned are the best to get done. People here have been told it is not autoimmune thyroiditis (Hashimotos) when their blood test show they have the very antibodies concerned!

If you have done 23&me there are things you can check in raw data to determine a genetic susceptibility but it is a bit of a sledge hammer to crack a nut approach. I did get genetic testing for the lymphoma on the NHS but I doubt they do it oir thyroid disorders.

You may search for an answer only to get even more questions!

I hope you feel well I would find that TSH a bit too high personally but it’s courses for horses with this lark! Going gluten free certainly helped me feel better. It avoids a lot of proceessed junk I don’t bother with proceed gluten free items. I stopped eating soya and that seems a step in the right direction too. Some say fermented soy is ok but I stopped that too.

We drew the short straw for sure!

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I agree with jimh111 , the main thing is, are you feeling well? I don’t believe the doctotrs will be withholding an answer, they just don’t know. Sometimes there just aren’t answers.

I have antibodies but was told the appearance of my thyroid on ultrasound didn’t fit with Hashis. It doesn’t matter because I’m feeling okay.

I’ve been hypothyroid for almost 20 years and levothyroxine has always suited me. Some on here aren’t so lucky. If you are not feeling well, then perhaps think about some of the advice re diet etc.

My TSH is always nearer 0 than yours too, so I’d say first port of call is back to your GP if you’re not feeling well.

Best of luck


Thanks everyone that's very helpful.

I know I've had the full antibody tests, next time I'll ask my GP for the exact numbers so I can be sure myself.

I've only been on medication for 3 years but my TSH has always continued to creep up. It was below 1 a few months back and the GP agreed to put me on 25mg extra on the weekend to try and get it back down.

I'd have preferred a bit more as I don't normally find such a small amount makes a difference, but I'll push the doctor for more when my next blood test comes back.

I mostly feel fine around 1 but start putting weight on around 1, even when dieting! I think I'm mostly a lucky one who levothyroxine works for. I know my mum has battles with the doctors over T3 and is currently self medicating.

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