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Thyroid UK
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Fast HR on Levo

So I've been hypo since 1992, on Levo which has been up and down since then. I asked to increase my dose recently from 200mcg to 225mcg as I was still symptomatic and TSH was top of range, now at 1.something. I do feel a bit better, certainly less depression symptoms.

I've never had a slow heart rate as far as I can remember, usually resting around 80, but my heart rate is now around 95-100 resting. I'm 39, a bit overweight, 5"9 and 13 stone.

I'm worried my GP will want to reduce my T4 if I mention my HR to him. Plus I was going to ask about T3 and having further blood tests done for B12, vitamin D etc, as these have never been tested, plus antibodies.

Does anyone have any thoughts on why it might be high? At least if my GP tries to reduce my dose I could say "yeah but it might be this..."

9 Replies


So I've been hypo since 1992, on Levo which has been up and down since then

Why has dose been changed? Any results from when it was - mention dose as well.

Do you have high antibodies - Hashimoto's? If not tested then ask, along with the vitamins and minerals. If your GP wont do them you can get them done with a private fingerprick test to do at home



Well worth it to get the full picture.


My dose of Levo has been up and down for as long as I can remember but it's only now I'm starting to question it. 30th June my TSH was 3.14 (0.3-4.2), FT4 10.9 (9-19) and FT3 3.8 (2.6-5.7), at which point I had started doing my homework so asked for an increase. Latest TSH was 1.66.

So I'm not hyper but why would my pulse be as high as it is?


Ask if online access to your medical record gives your blood test results. If it does, then ask for enhanced online access. It takes a few days to sort. You will have to take photo ID to surgery

You need to know if you have Hashimoto's also known as autoimmune thyroid disease. About 90% of hypothyroidism in UK is due to Hashimoto's.

Hashimoto's affects the gut, very often leading to low acid, low vitamin levels and leaky gut.

Extremely common to have low vitamin D, folate, ferritin and B12. If too low this stops thyroid hormones working

If you have Hashimoto's then hidden food intolerances may also be causing issues, most common by far is gluten. Changing to a strictly gluten free diet may help reduce symptoms and eventually start to lower antibodies. Very very many of us here find it really helps and is essential to be gluten free




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. Have you had recent band change?

Once you find a brand that suits you, best to make sure to only get that one at each prescription.

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


Thank you, I really appreciate your response.

I'm 100% certain there has been no change in brand or manufacturer in at least the last 6 years.

So if I am experiencing any of these various problems which can affect absorption or I have Hashimoto's, would any of these various issues cause an increased HR to your knowledge? Generally speaking those who are hypo suffer bradycardia, so why would I be tachycardic? I just want to be prepared for what the GP says!

Many thanks again!


You can get high Pulse when under medicated

Check vitamin levels.

1 like

Cheers! Will do.


You may be like me! White cost syndrome. I would sit outside in the car shaking with HR pounding when I was just going in to pick up a prescription! Thank goodness they are now sent to the Pharmacy!

1 like

Ha! Poor you!

No, I can categorically say I don't get white coat syndrome. My pulse is raised when I'm sat at home on the sofa or lying in bed.


Ah that's a different problem though I can do that if I over think things! But yes as as SlowGragon says you could be under medicated. The heart beat ( pulse) is sending the blood around your body and sharing oxygen and muneralsetc so if you are struggling it beats faster to get it there quickly.


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