Palpitations / heart thumps: Dear all, I have... - Thyroid UK

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Palpitations / heart thumps


Dear all,

I have been on Levo for six months now and my last set of results were TSH around 2 for a low-end-of-the-range T4 while taking 87.5 of Levo. (I am a LOT better than in November when I had a TSH around 7 and an under range T4.)

However, I can't stay on the 87.5 dose as I get palpitations. This has already been reduced from 100. I am now on 75 and I get around 4/5 heart thumps per day, whereas when I was on 87.5 I was getting loads, and lying down at night was terrible, I couldn't sleep for continual palpitations. I have split the dose to 25mcg 3 times a day each taken 4hrs after eating and 30mins before a meal where possible. I seem to tolerate this better than all in one go.


1. I don't think these palpitations are a sign of hyperthyroidism as I still have hypo symptoms, ie cold at night, tired, stiff joints - but all of which are improved. (I no longer have itchy skin and I am no longer completely freezing at night.) But then why do they happen? How common is this? It's not a racing heart, just irregular beats, thuds, "turning over" type stuff and it can be constant.

2. Does anyone know of any facts about heart issues being related to brand? I am not very sensitive to these things, and I can always tolerate all different brands of other medicine.

3. My theory is that it is too much T4 floating about at once, basically waiting to be converted - hence splitting into three doses. Does anyone know anything about this?

4. Finally, has anyone else had this and managed to solve the problem and get back up to the prescribed dose (in my case, 100)

Thank you for any help!


54 Replies

Palpitations can be a symptom of under-medication. And, with your TSH, you appear to be under-medicated.

It would be better if you could leave an hour before eating after taking your levo. You'll get better absorption. As you're already under-medicated, you don't want to compromise your absorption on top.

Love, T4, is basically a storage hormone. By itself, in the blood, it doesn't do much. I don't think it would cause palpitations.

Have you had your vit d, vit B12, folate and ferritin tested? It could be that you have nutritional deficiencies, and that would affect the way levo works in your body. :)

Thanks, Greygoose

The palpitations have got dramatically BETTER since dropping from 100 to 87.5 to 75. When I was on 100, for example, I fell to the floor and nearly got my daughter to call for an ambulance... and aside from this must have had 20/30 per day. Now at 75 I am down to 4 a day.

I want to increase my dose but have to do this without getting more palpitations.

Thank you for the advice on vitamins & iron etc, they are all slightly low and I am building them up!


You're welcome. :)

shawsAdministrator in reply to TakeCareOfYourself

I also had severe palpitations when on levo. The cardiologist was puzzled why this was happening and was going to put an implant in heart to try to figure out what was happening but when some T3 was added to T4, they resolved and I didn't need to see cardiologist again.


When I had them long enough to do an ecg - hours!! - I was camping and it was at night. I cut my dose and they stopped after 24 hours. I am not inclined to raise it again just to get a diagnosis but it might help with the GP to present stories of others who had similar reactions.

Do you remember the dosages?

shawsAdministrator in reply to TakeCareOfYourself

It was a number of years ago now. I believe I was on 100mcg of levo then dropped to 50mcg plus half T3 (equal to around 50mcg T4). I then dropped T4 altogether and took 25mcg of T3 for quite sometime and then increased by another 1/4. I have adjusted by a little at times but at present I take 1 and 1/4 T3.

Not being a good T4 to T3 converter caused my palpitations . The heart has T3 receptor sights . Adding a low dose NDT to my lowered T4 made a huge difference . Also adding some Iron helped . I tested low on Iron/ferritin levels .

How low is low ? Do you have the actual results for B12 - Folate - Ferritin - VitD ? B12 is good at 500++ - Folate and Ferritin are good mid-range and VitD at 100++. When all these are optimal many here have reported feeling better and with improved thyroid function with reduced symptoms.

Low iron = reduced oxygen transportation around the body which the heart can sense so could be the cause of an increased beat from time to time.

It was a funny heartbeat that took me to the GP here in Crete back in 2005. Heart was checked and I was told I could have many of these strange to me skipped/catch up beats per day. I was then checked for thyroid and all was revealed. My pulse runs high but no more funny heart beats. VitD was insufficient when tested - I inject B12 weekly - and eating liver keeps ferritin good. What supps are you taking ?

Hope you soon find answers ...

T4 shown to damage heart function, T3 levels similar to controls. I don’t agree with you that T4 is “just a carrier”!

I don't know which article you're referring to in that list of articles. But, if T4 did damage heart function, none of the population would live very long. The thyroid normally makes T4 and T3 and we can't live without it.

Plus, I didn't say that T4 was 'just a carrier'. And I wouldn't say that because it's not a carrier - what would it carry? I said, and I quote: T4, is basically a storage hormone. By itself, in the blood, it doesn't do much. I don't know where you got 'carrier' from that. T4 is a hormone. Proteins are carriers. So, whether you agree or not is irrelevant. :)

What is true is that low thyroid hormone level are likely to do far more damage than optimal levels.

Ooops, very sorry, posting way too late at night. The paper is below, and although its arguably not worth reading due to the small numbers / irrelevant backgrounds, still the subjects had the same T3 levels, but differed in T4. Those with higher T4 who had thyroid issues and were taking T4 meds, had resulting heart problems or at least differences.

Quote “These findings indicate that long term levothyroxine therapy at suppressive doses markedly affects cardiac function.”

I’m simply arguing that it’s not safe to say that “by itself in the blood it doesn’t do very much”. Sorry to confuse storage with carrier, I had remembered incorrectly that you’d said it stored something.

I may l

Cardiac effects of long term thyrotropin-suppressive therapy with levothyroxine

B‌ Biondi, S Fazio, C Carella, G Amato, A Cittadini, G Lupoli, L Sacca, A Bellastella, G Lombardi

The Journal of Clinical Endocrinology & Metabolism 77 (2), 334-338, 1993

I have never argued that we should not medicate. If anything, it’s an argument for including T3. However, I have not researched this and am sure others have.

I would have thought that T3 is far more likely to damage the heart than T4, being the active hormone. But, palps do not suggest damage to the heart, they are just a symptom of over or under-medication, hypo or hyperthyroidism.

But, the research that you indicate - which is rather old - was not aimed at proving that T4 caused heart damage, but that suppressed TSH caused heart damage. Something which has since been disproved.

The cursory reading of data seems open to either interpretation.

I agree, palps are not necessarily indicators of damage, but contribute to strokes, and I am wanting to track down why I’m getting them.

Then look to your nutrients. If they're not all optimal, your body won't be able to use thyroid hormone correctly, and you won't be able to tolerate increases in dose.

Also they get better when I split my dose.

When I have time to research this I’ll share and enjoy discussing with you! Meanwhile do you know why they don’t go straight to artificial T3 as it is the active thyroid hormone? Is it just cost, or are medical reasons involved?

Both, I believe. Although, certainly in the UK it's strongly based on cost. However, starting on T4 gives a good indication of how you're going to react to thyroid hormone replacement. And, it's also the easiest to stabilise.

But, there is also a strong financial reason in that T4 is a commercial product, patented and sold by Big Pharma. It used to be that people were started on NDT, because that's all there was. But, then, someone invented synthetic T4, and BP started a campagne to demonise NDT, blacken the name of T3, so that they could sell their levo. As BP controls the purse strings in med schools, it came to be that doctors only learnt to treat with levo and dose by the TSH, and learnt nothing about NDT or T3 or understanding blood tests when taking either. Doctors became like robots with little understand of thyroid at all. They don't know what T3 does, or why it's necessary - a lot of them think it's the same thing as T4! - a lot think that T3 converts to T4!! - simple examples of how bad their education is, and that's deliberate on the part of BP. They also don't want doctors knowing how to get hypo patients well because they make an awful lot of money out of 'treating' hypo symptoms as separate diseases: statins, PPIs, Beta blockers, antidepressants and all the rest. It's a complicated system that has been simplified almost out of existence: prescribe levo, get TSH back to somewhere in range, job done. Which is why so many hypo patients continue to suffer.

That’s really interesting, thank you. I feel I have some background now :)

You're welcome. :)

jgelliss in reply to greygoose

For sure . I agree with you greygoose 1million percent . BIG PHARMA has a Big hand in our meds and Pockets . For many myself included T4 alone does not work well .It's been proven . Yet Medical Academia and Big Pharma will have you believe that T4 converts into T3 . Not for me . There is a *Tremendous* *Need* for T3/NDT meds and yes we need T4 too for those that do just fine on T4 only because they are good converters . Many like myself are *Not* .

shawsAdministrator in reply to TakeCareOfYourself

There are many researchers who've proven that T4/T3 is beneficial for many but the 'powers that be' who've never had hypo disagree and insist on levo alone. I have read that when levo was first introduced (in USA I believe) that doctors and endocrinologists were paid to prescribe levothyroxine. Would that come under the word 'corruption'. Also if we count in the 'other prescriptions' prescribed to try to control the other disabling symptoms they're making lots of money.

T4 has receptor sights too IMHO . My brain works off of T4 . I can tell you from my personal experience when my T3's are higher and my T4's are low my concentrations are almost none excising and I feel T3 drunk . It's *very individual* . I know some that need a much higher T3 and don't even dose with any T4 and that works great for them . It must be how we individually metabolize our thyroid meds and what our system does with it . It's not one size fits all . *It's More Art Than Science* .

greygoose in reply to jgelliss

Actually, I don't think your brain does work off T4. The T4 is converted to T3 in the brain. :)

jgelliss in reply to greygoose

Thank You so Much for your very kind reply . You are *Very Right* when you say the brain needs T3 for adequate mental function . Is it Possible that direct T3 verses T3 deiodinased from T4 works for some of us better especially when personally higher dose of T3 makes me lethargic ? There are many studies that show/prove that direct T3 *helps* with depression . There are many cells that need direct T3 . The Heart has T3 receptor sights as well .

As for my own experiences only . I do much better with low dose T3 for my higher dose T4 . I tried the other way around with higher dose T3/NDT to a much lower T4 . I just felt T3 drunk , estrogen dominant and very irritable and gained lots of weight .I was/am and continue to be my own *Rat Lab*.

I'm sure many thyroid patients will find that they do so much better with high doses of T3/NDT with low/no dose T4 . It's very individual and we ought to respect that too . It's not one size fits all by any means .

greygoose in reply to jgelliss

Indeed we must. It's a very individual thing. But some psychiatrists do treat depression with direct T3, that's true.

I had heart palpitations when I was taking levo as well as light headedness & anxiety. Every night I would wake up with my heart thumping out my chest. I was also exhausted all the time.

I tried everything I could think of - I was put on iron tablets, had b12 injections & went gluten free.

In the end I was admitted to hospital where everyone was just scratching their heads. I saw an endo & begged to be allowed to try t3 only.

I had to start on a very low dose & build up gradually & it took a long time to get well, but I can now function fairly normally.

I hope you can find a solution that works for you x

Thank you, Newday. I am glad you have got there. It’s certainly something I will consider - the battle that people have gone through is off-putting and I am not a fighter... but I will do my research and approach the gp at some point. Thank you for sharing this. Helen x

Keep pushing till you get there! You deserve to feel better. I'm believing for better days to come!

I had the same problem when I was new to levothyroxine. After about 4 months I got up to 88mcg and that's when the trouble started. I had bad racing heart and hypoglycemia. I discovered my body couldn't handle a low TSH of 0.4 and that 88mcg was probably too low. I ended up reducing to 50mcg. The palpitations and the hypoglycemia disappeared. My TSH is now 2.5 again and I'm beginning to feel aches and pains again telling me it's time to raise it again. I find my body is very sensitive and I know if I raise it my heart rate will increase again, which I find scary.

I find when I raise it my TSH reduces very quickly and I get palpitations and as my body gets used to it everything it settles down. Having low ferritin in the early days also caused me problems.

Your body may just be sensitive like mine as I was hypo so long without treatment I find taking it easy and raising slowly workß for me.

Thank you, sounds as though we react similarly. I can’t understand why there is this reaction though if it’s basically an identical hormone. Did your TSH get so low because your T3 was optimal? Or something else going on?

No my T3 is still not optimal. I think my TSH reacted too quick as it has bounced back to 2.5 now. I think my body wasn't happy as low T4 and 0.4 TSH. On 50mcg my TSH has stabilized. I think I've been hypo all my life so getting T4 was a shock. I'm 61 now so I'm going to up it slowly allowing my body to adjust till my T3 is optimal.

SilverAvocado in reply to magsyh

Magsyh, the symptoms TakeCareOfYourself describes don't sound like this, but when I saw the headline I thought of adrenal problems. If you get the kind of palpitations that go with a speeded up feeling, restlessness, feeling hot, fast digestion rather than slow, etc. it may apply to you.

I do think, TCOY, if you're searching around for solutions you might as well look into adrenals, as even though what you describe doesn't sound typical, it sounds kind of related. The reason these can cause trouble when we introduce thyroid hormone is that the whole metabolism increases. Ever organ and cell in the body needs thyroid hormone, so as it starts getting through and giving that faster metabolism, it also means more demands on these organs and cells that aren't used to it. The adrenals take on a big share of the work of coping when we're hypo, and also have to do more work as the metabolism increases.

The first line of treatment for this is to reduce stress, rest well, sleep well, learn to meditate and relax, eat well (particularly in ways that don't stress the body, not restricting calories or skipping meals), cut out strenuous exercise but bring in gentle exercise like walking or Tai chi. Fix vitamin deficiencies, and ultimately get thyroid hormone optimal, too.

If the issues are caused by stressed adrenals you can also do any increasing super slow. Cut or grind tablets to do very small increases and give the body a long time to get used to it.

magsyh in reply to SilverAvocado

I've had adrenals tested twice. Always says normal but I know it's my progesterone supplement that keeps them going. I've had a very stressful life and get ill if I'm stressed. I'm taking the levothyroxine at my pace as I can tell how my body reacts now. My hypo is also central not primary so I think that's why but my GP hasn't a clue. My prescription is private but I now buy my own coz it's cheaper.

SilverAvocado in reply to magsyh

Have you had a 24-hour saliva cortisol test? Unfortunately this is not available on the NHS, but the ThyroidUK website tells you how. The NHS blood test is testing for Cushings and Addisons disease, which are the extremes of under and over active adrenals, and it's not that common to be both hypothyroid and have either of these.

The saliva test picks up the adrenal glands struggling, being out of rhythm or cortisol and DHEA (a precursor to cortisol) being too low or too high.

magsyh in reply to SilverAvocado

I have had 24 HR saliva, rhythm normal, dhea normal. Progesterone is keeping it that way. If I didn't have the extra progesterone then I think it would be a mess. My private doc told me it's that, that keeps it all stable. My body reacted badly to the progesterone at first same thing palpitations. He says I have shaky adrenals.

This is really interesting, thanks, and good advice for life in general really!

I had palpitations, but only when my T4 was 36. My doctor friends mutters atrial fibrillation to me whenever he sees hoe much weight after lost!

Thanks, Janet. 36? Unusual dose!

I’d just had my thyroid removed and was given too much levothyroxine. But I was told atrial fibrillation is a risk for me as I have to have a low TSH for a couple of years and I’ve had cancer. So it’s. Known thyroid risk.

Thanks, Janey. So it seems to be a low TSH issue? Not high T4.

In my experience all symptoms are pretty much hypo/hyper interchangeable. I remember a lady on here saying if her dose is too low her hair falls out and likewise if too high.

I see. Thank you for your input. In my case, my heart turn-overs stopped instantly (24 hours) of lowering dose so I don’t think they are hyper symptoms or they would have a slower response time. My bloods were also with T4 low end of normal and TSH 2 so not hyper either.

This is why I think something else is going on and want to get to the bottom of it, as heart issues = not good :)

Hi Helen - for me a loud thumping slow heart (anything as low as 40 beats / min) is low thyroid and a racing heart 90-100 beats / min is high/excess thyroid. Which do you think you have ?

Neither, I have normal heart rate (72 bpm) but with sudden thumps or palpitations, either one-offs or lasting 4-10 seconds. It is never racing, and never slow - even when off meds I did not have a slow heart.

I don’t think it’s hyper or hypo, I think it’s actual drugs in my system if you see what I mean - T4 hanging around waiting to be converted. But I don’t know. It is better if I split my dose.

I split my T4 dose AM and afternoon and it works very well for me .

Yep I’ve just split it down to 3 x day, good at 75 so far, will increase by increasing to 100 for two days a week only. Slowly!

Hang in there . You'll get there . Be kind and patient with yourself .

Best Wishes for a Successful Outcome .

I agree that heart symptoms occur with undertreatment as well as overtreatment and to get rid of them it seems that it’s necessary to find optimal treatment AND continuously take the same dose. It may be helpful if you monitor and record your pulse rate at times when the bumps are not happening so that you build up a record of pulse rates at different times of day on different treatment doses. These can be used to inform dose change. It may be that your heart is ‘out of condition’ due to hypothyroidism and a very gradual increase is necessary. I personally found that daily gentle exercise was helpful throughout thyroid dose change, but be careful to avoid overdoing it.

Thank you :)

I agree, and good suggestions.

I can only take certain brand of Levo or I get symptoms much worse.. been told I have hydrothyroidism yet I over heat especially at night ... I don’t get cold ?

Do you have your FT3 FT4 TSH tested ? You might not be a good converter T4 to T3 and you might need some T3/NDT added to your T4 dose .

Nutrients like Vitamin "D" /K2 , B12/folate , Iron/ferritin if you test low (low iron can cause palpitation /thumping) , magnesium , vitamin "C" , Celtic Sea Salt for adrenals/electrolytes .

Check if the fillers/dyes are causing some of your symptoms too . I was on Synthroid and it caused me many symptoms . Switching to a different brand without dyes made a huge difference for me . Going gluten dairy coffee free also made a huge difference . Coffee /chocolate sugar soda was very stimulating for me and caused me palpitations too . Being a thyroid med depended I think set me up personally for more allergies to food/nutrients etc.

Best wishes .

Thank you - I think I’ve got to keep a record! Not my forte!

I'm sorry that I don't have the time to read through all the replies you've received but I hope someone has told you that palpitations can frequently be caused by anaemia. Also I believe a lack of B vitamin can cause palpitations too.

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