Thyroid UK
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High blood pressure

Hi all, im worried about my blood pressure. I,m 46 years old, slightly overweigh, training an hour and a half a day 6 days a week for a triathlon, eat high fat low carb and have hashimotos. I take 125mcg thyroxine daily and my blood pressure seems to be about 140 over 79 most days when i take it. my thyroxine has been reduced over the last 6 months by my gp as my t4 was higher than normal range.

Weight gain and constipation bad since my dose lowered. could low thyroxine cause high blood pressure?

What can i do about my high blood pressure feeling scared right now. thanks in advance

6 Replies

I'm sorry you're having a rough time at present. Lots of symptoms, when our dose is lowered due to the blood tests alone, may appear for the first time.

If you have a copy of your latest blood test results with the ranges, can you post them so that members can comment.

There's no history on your profile and I've looked at a couple of past post and you have hashimotos. Did you have your latest blood test at the earliest possible, fast too and leave about 24 hours between your last dose of levo and the blood test?

When your levo is reduced only upon blood test results it can cause more symptoms.

I note you exercise daily and if we aren't on an optimum of thyroid hormones it might be the cause of a reduction of T3 which is the active hormone required. I assume your GP hasn't tested your Free T3 and if you've not been converting levo to sufficient T3 , that might be the reason you feel bad. Ask your doctor if you can have a Free T3 test as that will show whether or not you are converting T4. She may refuse but you can get a Free T3 from a private lab.

This is a link re levo and blood pressure:-

Below is a new article published in The Lancet by Advisers to Thyroiduk.

plus an Open letter to the BTA etc. your GP may like a copy of both.


hi Shaw

thank you for your reply,ill get my results from GP and post them. I've sent my Thyroid panel test off to blue horizon today x

1 like


I can understand how you feel I to had a problem with my blood pressure going up and down .

So purchased a monitor from Lloyd's Chemist was only £9 99 instead of £19 99 tested 3 times a day for a week 121/65 to 154/78 saw GP today who says as long as under 140/85 I should be happy as that was very good.

One thing less to worry about

Best Wishes Rose


thank you Rose put my mind at rest a bit.x


Yes, low T3 can cause raised blood pressure. And your T3 is probably low due to your dose reduction plus all the training you do.

It's quite possible that you Don't convert very well, so you needed your T4 over-range to get enough T3 to keep you well. Lowering your T4 will obviously lower your T3. Another stupid doctor! :)


Thanks green goose. On my test before last my TSH was under 1 but my t4 was slightly above the reference range. My doctor told me too high t4 would cause me to have a stroke to lowered my dose. Now i ha e high blood pressure! And he won't increase my dose again


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