T3 and high blood pressure?: I have been on T... - Thyroid UK

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T3 and high blood pressure?

bambuko profile image

I have been on T3 now for six month.

To my surprise I have noticed rather high (160/110) blood pressure recently.

I have a history of slightly raised blood pressure, originally treated with medication.

I have managed to improve my blood pressure and get off meds by loosing a lot of weight (at least that's what I believe), and been OK for the last few years, so recent and unexpected increase is concerning.

Doubly concerning since both my father and grandfather died relatively young from brain hemorrhage.

Now... the only thing different in the recent past is me starting on T3, so it is possible that my increased blood pressure is related?

Of course I am not keen on messing with T3 either, because:

a) it took a lot of effort to get it

b) it is actually working...

What do you think?

20 Replies

Hi! I'm afraid I cannot offer any solution - but I share your concerns about high blood pressure since I come from a family with a history of hypertension, stroke and heart problems. I have hypertension too on top of hypothyroidism but I monitor it as and when I suspect it may be going high - my last reading wasn't so bad - 119/68, heart rate 61.

I feel that is worth me monitoring my own blood pressure due to my family history so, yes, I hear you about why you would be concerned.

I hope someone can offer you more help than I can and I am sorry your grandfather and father passed away, my condolences. ❤️❤️

SlowDragon profile image

Well you need to get FULL thyroid and vitamin testing done

All tests should be done 6-8 weeks after being on constant unchanging dose and brand of levothyroxine and T3

For full Thyroid evaluation you need TSH, FT4 and FT3 plus both TPO and TG thyroid antibodies tested. Also EXTREMELY important to test vitamin D, folate, ferritin and B12

Low vitamin levels are extremely common, especially if you have autoimmune thyroid disease (Hashimoto's) diagnosed by raised Thyroid antibodies

Ask GP to test vitamin levels

Recommended on here that all thyroid blood tests should ideally be done as early as possible in morning and before eating or drinking anything other than water .

Last dose of Levothyroxine 24 hours prior to blood test. (taking delayed dose immediately after blood draw).

This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip)

If/when also on T3, make sure to take last third or quarter of daily dose 8-12 hours prior to test, even if this means adjusting time or splitting of dose day before test

Is this how you do your tests?

Private tests are available as NHS currently rarely tests Ft3 or thyroid antibodies or all relevant vitamins

List of private testing options


Medichecks Thyroid plus antibodies and vitamins


Thriva Thyroid plus antibodies and vitamins By DIY fingerpick test


Thriva also offer just vitamin testing

Blue Horizon Thyroid Premium Gold includes antibodies, cortisol and vitamins by DIY fingerprick test


If you can get GP to test vitamins and antibodies then cheapest option for just TSH, FT4 and FT3

£29 (via NHS private service ) and 10% off down to £26.10 if go on thyroid uk for code



Also vitamin D available as separate test via MMH

Or alternative Vitamin D NHS postal kit


bambuko profile image
bambuko in reply to SlowDragon


I have all the tests (both private and NHS, although as is usual last one ignored T3 even though consultant clearly requested it...) done every 3 month under the care of consultant endo.

All the usual advice about timing etc is followed (although the advice is worth repeating).

Vitamin levels are tested as well (although testing B12 is pointless? since I inject once a week).

My question is more about the dilemma what to do... with T3 and high blood pressure.

If (as I suspect) higher than usual blood pressure is caused by T3?

do I:

a) take meds to lower blood pressure (not keen on it)

b) cut T3 (not keen on it)

c) something else?....

SlowDragon profile image
SlowDragonAdministrator in reply to bambuko

Well what are your most recent results

On almost any dose of T3 TSH is frequently suppressed, and, if not taking high enough dose levothyroxine and T3 you can actually be more hypothyroid. Always essential to test both Ft4 and Ft3

What dose levothyroxine and T3 are you currently taking

How much was levothyroxine reduced when T3 added?

Frequently levothyroxine dose needs increasing if Ft4 is too low

Far too frequently medics keep reducing dose levothyroxine, rather than increasing

Many people on levothyroxine plus T3 need Ft4 and Ft3 at least 60-70% through range, sometimes higher

High blood pressure usually suggests under medicated

There are multiple factors which can influence blood pressure. Hypo and hyperthyroidism can lead to aortic stiffness and can increase blood pressure. In most cases, when the hypo or hyperthyroidism is corrected, the hypertension does regulate itself.


T3 is associated with increased contractility of the heart and can lead to increased cardiac output (more blood being pumped through the heart). Have you had your T3 measured? If it is still in range, this should not cause your blood pressure to increase.

If you have had hypertension problems before your thyroid problems, there could well be a genetic component to it and this may just present itself again.

Other factors I can think of, did you have any medication or treatments for anything recently? Some medication can increase blood pressure, and it may take a while for the blood pressure to settle after you have stopped the medication.

Also, has your exercise levels changed and you are doing perhaps less?

Just some thoughts, if your T3 is not outside the range, I would check other factors first before thinking of T3, especially since you are doing well on it! :-).

bambuko profile image
bambuko in reply to Tina_Maria

Thank you both SlowDragon and Tina_Maria

I have only started on T3 with consultant 6 month ago, so only had two tests and two adjustments.

It is slow process as you all know...

I am currently on 125mcg of Levo and 20mcg of Lio and waiting next three month for the test to see if the results are better.

My Levo previously was anything between 250mcg and 125mcg.

Immediately before T3 I was on 200mcg of Levo

Apart from T3 there were no medication changes.

My blood pressure was OK last three years (after I lost 25kg off my belly etc).

Recent change in my blood pressure is sudden and quite dramatic (190/100).

I am off to have a blood test tomorrow and hopefully talk to my GP on Friday.

Hopefully it will get better once my thyroid meds are sorted...

SlowDragon profile image
SlowDragonAdministrator in reply to bambuko

That’s a dramatic drop in levothyroxine dose

We frequently see that levothyroxine dose is dropped far too much when T3 added

We often need GOOD Ft4 and Ft3 levels — at least 70% through range......regardless of how low TSH is

Do you always get same brand of levothyroxine?

Always test as early as possible in morning before eating or drinking anything other than water and last dose levothyroxine 24 hours before test

Last 5mcg of T3 roughly 12 hours before test

bambuko profile image
bambuko in reply to SlowDragon

Well... the blood test tomorrow is at the request of GP, so the lab will ignore T3 (they even ignored it last time when it was done at the request of the consultant...).

Part of the problem is that I am doing consultant's blood tests locally, to avoid travelling and exposure to hospital.

It doesn't work very well - hospital and local GP practice use different computer systems (they don't talk to each other...). Both of my last two tests were lost and took forever to find.

Plus, last time the lab didn't do what was requested.

At least endo increased T3 regardless of the lack of test numbers, just based on symptoms.

I was on 200 mcg of Levo from end of 2017 until March 2020 and on 100mcg until December 2020 and 125mcg since.

The usual yo-yo of doctors chasing TSH numbers ...

My T4 is fine - 15.2 (range 12-22)

TSH is still high at 11.08 (range 0.27-4.2)

T3 is still only 2.3 (although slowly better than previously)

SlowDragon profile image
SlowDragonAdministrator in reply to bambuko

Just test via Monitor My Health

Do test at home pop in post

just TSH, FT4 and FT3

£29 (via NHS private service ) and 10% off down to £26.10 if go on thyroid uk for code



All tests should be done as early as possible in morning before eating or drinking anything other than water and last dose levothyroxine 24+hours before test

Last 5mcg T3 roughly 12 hours before test

Obviously need to test vitamins too at least once a year especially as you are so hypothyroid

Medichecks usually cheapest

SlowDragon profile image
SlowDragonAdministrator in reply to bambuko

Obviously need to stop any supplements that contain biotin a week before ALL BLOOD TESTS as biotin can falsely affect test results

FT4 rather low in range at last test

Only 32% through range


Tina_Maria profile image
Tina_Maria in reply to bambuko

Is your TSH really 11.08?? That's awfully high, if you are on replacement therapy, it should be below 1 for you to feel better. This actually indicates that you are severely hypothyroid, T4 is also far too low and I bet the T3 is also right at the bottom of the range if not below. You need a lot more medication to dig you out of that.As I have mentioned above, you seem to be severely hypothyroid, which increases arterial stiffness, which in turn can increase blood pressure as the body will find it more difficult to pump blood through. Also, if your T3 is very low, your heart muscle will have to work a lot harder to pump the blood through, which can also put strain on your heart muscle.

If I was you I would insist on an increase in medication pretty quickly. Good luck!

bambuko profile image
bambuko in reply to Tina_Maria


My TSH is a lot better than it was in the past,

Only last Sept it was 17.97

Highest it has been was 22.85

It was only ever any good when I was taking 250mcg of Levo

T4 tended to hover around 20 historically.

It's only since recent changes it went down 4 month ago.

T3 (since I started testing it privately) was always below the range


thanks for the links.

I will check Thyroid privately again.

rather than hope that NHS will do what's being asked...

SlowDragon profile image
SlowDragonAdministrator in reply to bambuko

Waste of time and effort expecting/hoping NHS will do full test

bambuko profile image
bambuko in reply to SlowDragon

They did test T3 in September at the request of the consultant...

but missed it in December despite identical request from the same consultant

so, I don't know what's going on

perhaps someone had a bad day?

Next official test in March.

Tina_Maria profile image
Tina_Maria in reply to bambuko

The sad reality is concerning proper thyroid tests, the NHS always seem to have a bad day. They are just not bothered to be honest, especially at the moment, when no other condition seems to exist except Covid :-(

They test TSH and if you are lucky T4 and that's it - anything else just does not fit within their treatment guidelines and thats the end of the story as far as they are concerned.

Like SlowDragon has mentioned, you should get a private test done with full panels of everything, I would check vitamins and minerals as well to be on the safe side. I know its not cheap and we are all a bit tight on money these days, but this is your health and unfortunately waiting for the NHS to get their act together, will not help you get out of your predicament any time soon. Being proactive is always good and it will also give you a boost, that you are working towards getting better. I know the mountain seems very steep to climb, but every step you take will get you closer to feeling better! :-)

Having these tests will also give you more leverage with the GP and consultant - if they see it, it will be a lot more difficult to ignore it!! :-)

bambuko profile image
bambuko in reply to Tina_Maria


Yes, I've been doing private tests and that's what eventually got me to the endo consultant...

Have you been more stressed or tired lately?

Some tips you can follow immediately: drink plenty of water, give up coffee, cigarettes, alcohol, eat healthier and less salty, take magnesium. I think it would be useful to have a mild hypotensive in the house (something that is held under the tongue) and take it when the blood pressure rises too much.

You should also discuss this with your doctor about giving a referral to a cardiologist.

bambuko profile image
bambuko in reply to ilenuca


I have stopped smoking over thirty years ago...

I have stopped tea, coffee and alcohol over three years ago.

I eat very healthy (as far as I am concerned) although the science of nutrition barely deserves the name of "science" - too much biased quackery and poor epidemiological research that at best establishes correlation without proving causation...

No stress in my life - happily retired 👍

The only stress in my life is thyroid and all the mess it causes ...

as for the referrals... it all seem to be revolving around Covid at the moment

the waiting lists gone crazy

I will see what the results of blood tests etc are...

Simplyred57 profile image
Simplyred57 in reply to bambuko

Hi just wondering if you resolved your high blood pressure? Mine has suddenly gone very high and I took a urine sample in yesterday so they could check the overnight protein related to high pressure, and thyroid bloods tomorrow, I reduced my T4 from 100 to 75 on my endocrinologist instructions to try to bring my T3 &t4 down a little but I feel terrible- I like you think the T3 is somehow related 🤷🏼‍♀️

bambuko profile image
bambuko in reply to Simplyred57

I am monitoring it and waiting... hoping that liothyronine changes eventually settle things down.

My bloods came back all fine ( I am waiting with thyroid blood test until two/three month since last chnage - no point doing it earlier)

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