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Thyroid UK
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High blood pressure


Does anyone know if an underactive thyroid can cause high blood pressure please?

I was diagnosed about 4 years ago and struggle to get my GPs to increase my medication as I am still having the usual problems, i.e., tiredness, ( need over 10 hours a nigh sleep and still tired ) overweight, ( even though I am on a healthy diet ) and I have chest pains, light headedness, anxiety etc

. I was invited to a free NHS health check a couple of weeks ago and my blood pressure was high ( 167/96 ) The nurse asked me to monitor my blood pressure at home for 2 weeks. ( due to go back tomorrow ) I had the usual blood tests, and asked for one for the thyroid and should get the results tomorrow. I am now wondering whether being under medicated could be the cause of my high blood pressure.

Thanks for listening.


7 Replies

It's quite common for untreated or undermedicated hypothyroidism to result, over time, in high blood pressure (even when the initial impact can start out as low blood pressure). How were your readings at home?

You might want to read about secondary hypertension (secondary to the hypothyroidism) and see if it matches your experience.

I hope that there's a clear outcome for you that involves assessing your thyroid function more fully rather than opting for a prescription for medication to lower the BP without looking at potential contributory factors. Good Luck.


Thank you for your kind and speedy reply. I will certainly take your advice.

My bp readings at home have fluctuated wildly. Here are a few. 167/101 139/95 128/83 132/91 124/83 140/88 146/98 122/96 and 137/102.



Post you most recent blood test results including ranges

Do you ensure to get blood test as early as possible in morning and fasting and don't take Levo in the 24 hours prior to test, delay and take straight after.

Also have you had vitamin D, folate, ferritin and B12 tested recently

Plus I see from older posts you have Hashimoto's - very common for vitamins to be too low

With Hashimoto's it's very likely hidden food intolerances can be causing issues, most common by far is gluten.

Changing to a strictly gluten free diet may help reduce symptoms. Very, very many of us here find it really helps and can slowly lower antibodies.







Thank you for replying so quickly.

My apologies for a long winded reply to you!

I had a blood test in June 2017 ( usually have one every 12 months ) and TSH was 5.5 ( range is 02 -4.00 ) GP asked ( over the phone ) what my symptoms were and I explained that they have never gone away since being diagnosed - just improved slightly, but recently got worse, so she agreed to increase my medication and asked me to take another blood test in 3 months, which I had 2 weeks ago.( will ask nurse for results tomorrow )

Apart from the first year of diagnoses, they won`t test for T4. Only TSH. I have not had any other tests offered to me and have not seen a gp since. I arrange for a nurse to give me my annual blood test, ring the results and the receptionists usually say - satisfactory. They will not give me my levels so I have to ask someone to ring me to tell me them.

It`s only because of the surgery inviting me to a health check ( with a nurse ) that I have had my blood pressure taken.

I`m not even sure I have Hashimotos as one gp said if I haven`t got a goitre I don`t have Hashimotos!

Thank you for listening.



Well like very very many of us on here, (certainly 100's, possibly 1000's) you will need to organise your own private tests


Medichecks Thyroid plus ultra vitamin or Blue Horizon Thyroid plus eleven are the most popular choice. DIY finger prick test or option to pay extra for private blood draw. Both companies often have money off offers. DIY finger prick test or option to pay extra for private blood draw or organise your own blood draw.

All thyroid tests should be done as early as possible in morning and fasting and don't take Levo in the 24 hours prior to test, delay and take straight after.

If your vitamins are low, then you can supplement without involving GP m unless B12 is very low in which case full testing would be needed for Pernicious Anaemia and intrinsic factor

If you have high antibodies then you know to look at food intolerances, usually gluten

Great film definitely shows why just testing TSH is inadequate


Always take Levo on empty stomach and then nothing apart from water for at least an hour after. Many take on waking, but it may be more convenient and possibly more effective taken at bedtime


Many people find Levothyroxine brands are not interchangeable. Once you find a brand that suits you, best to make sure to only get that one at each prescription.


Thank you so much!



You should find this link of interest :



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