Thyroid UK
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OK Vitamin D effects calcium, so what's the connection with 'calcium channel' blockers like beta blockers given for palps etc?

Researching any ill effects of taking Vit D supplements.

I feel so much better but still have occasional nasty palpitation feelings & jittery esp at night (although I've learnt to deal with them). I'm not on any meds although I know I'm hypoT. (offered beta blockers, borderline TSH, palps less after half thyroid out, but still knackered!).

Anyone know the connection? What IS the calcium channel? Experiences & theories welcome. Jane :D

15 Replies

A very good question.

As I understand it (leaving lots out - either because I do not understand or know, or because I am trying to keep it simple)...

A calcium channel is (sort of) a controlled hole in the cell wall of a cardiac or blood vessel cell. It is concerned with how calcium moves between the interior of cells and their environment. Individual calcium ions (an ion is a charged atom) are pumped into a cell. This is a bit like charging a battery. At some point, the cell decides to fire and the ions are ejected to do so.

A calcium channel blocker reduces the amount of calcium that is moved into a cell before it fires. So when it fires, it has less oomph. This results in the artery being more dilated than otherwise.

Whereas beta blockers affect the sensitivity of beta receptors in the sympathetic nervous system to those substances which would otherwise make the nerves fire more - the classic example being stress, and most especially stress when there is already significant adrenaline.

I am not at all clear of the relation of vitamin D to calcium channels - rather than calcium handling in terms of bone or plaque build-up. This is an area that most definitely requires more understanding of the processes than I have!



thanks Rod, I read your reply 3 times trying to understand.

Do beta blockers dampen things down then? but don't they also have an adverse effect on low Thyroid function somehow? (I have low blood pressure so they're not for me) conversely Vit D generally makes things work better - don't most folks feel better in the summer? (but I'm mindful of it helping rat poison work faster!).

All this calcium, ions & electrolyte balance stuff is confusing! I think we're just solar-powered batteries connected to the 'matrix-like' body, hence the heart rhythm can be affected too.

Meanwhile I'm not hibernating this year, so that must be better. J :D


Yes - beta blockers stop the adrenaline from making heart go quite so tickety.

Yes - beta blockers reduce the ability to convert T4 to T3.

Yes - many people report feeling better with decent levels of vitamin D. (Except the rats. :-) )

Yes - all this calcium, ions, etc. *is* complicated and confusing.

I have sometimes thought of it like a camera flash. That is, one of the electronic ones. With the right battery, the flash charges up. When button pressed, flash fires and light goes in required direction. That is, a signal is sent. Then the flash has to charge up again before it can fire again.

But if the battery is the wrong voltage, it won't work! And in that sense, calcium has one voltage and sodium has another! So calcium works on a calcium channel and sodium works on a sodium channel.


HI You do not say why you are taking these drugs. They are sometimes used for high BP ,if Ace inhibitors are contra indicated, Ace inhibitors are the normal drug for high BP, but you say yours is low.They will both lower the sounds as if you have AF? has it been diagnosed by a cardio ? If so beta Blockers and calcium channel blockers are sometimes used for high . BP and mild AF for bad AF the drug then is Amioderone, that does lower the thyroid considerably.Beta Blockers should always be taken after the thyroid test, before they give a false reading. I have been on them for years and discovered that beta blockers alter the test result if taken first but not the results when taken after , I have bloods for thyroid done every 2 to 6 weeks depending on my other conditions and drugs. This view of Beta Blockers has been born out by a small trial in Glasgow ( sometime ago) but I knew from my own observation. I am on all the well known heart meds. mostly high doses. calcium channel blockers are usually used as a last resort for heart.,my arteries are fine. I was on them for over a year with all my other cardiac drugs for my AF and VT`s which are largely uncontrolable. I had a lot of side effects and they made my ascites ( Tum fluid) very bad indeed.However, my grand daughter , was put on calcium channel blockers by GOSH when she was 9 ( now almost 13) She has them for Raynaulds and to help her migraine. This if to give the other viuw. I can only go by my own problems with it. it was also the view of the many other cardiologists that I came across in my many in patient cardiac admissions. My own cardio tried them for me as we were both desperate. I hope this enables you to make the right choices for you.

best wishes,



Hi Jackie,

No I'm not taking any medication.

However I was prescribed beta blockers for my palpitations a while back - & didn't take them as I wanted to know what was causing the symptoms of 'anxiety' as I wasn't anxious, and asked the doc 'why couldn't it be something physical? Eventually I had a Thyroid nodule removed & 'anxiety' symptoms went.

I wonder how many other Thyroid sufferers get prescribed them instead of the correct treatment, fine if they help...

Since the op I've become hypoT (I may have been before, I don't know) but when a Vit D test showed I was low, I went to the GP but was told to go to 'Boots' for supplements. I have taken supplements since April and felt better but experiencing palpitations again.

So I just wanted to know the calcium connection. Jane :D


magnesium is natures calcium channel blocker, and if you take it with vitamin K2 (you can get some in brie and gouda) it shifts the calcium from the soft tissues into the bones where it should be. I use it for high blood pressure and heart palpitations and arrhyrthmia by taking magnesium malate. Magnesium oxide or sulfate are not as effective, there are lots of forms of magnesium and I am not sure about a lot of them, but I know some are good for absorption and some better for constipation. Dr Mercola has just done a piece on his newsletter today, about magnesium, a forgotton mineral, see if you can find it as I can't seem to post it - sorry!


Hi fennel.

it is not safe to take magnesium without a blood tests to show you are deficient. It has a very small range and also effects the potassium. these and sodium and calcium are the main electrolytes and essential they are in range as otherwise very dangerous to heart and kidneys. There is a simple test , separate, for both magnesium and calcium ( corrected calcium) and the others are U`s and E`s. If any one needs either calcium or Magnesium it needs to be on a script, with frequent blood tests. sodium ( Na) is of course in our own hands. The magnesium I have to have is used for kidney transplants and is oxide magnesium, I am reliably informed and found it is one of the best for absorption. Magnesium in a drip is best in hospital, if very low as better absorbed and safer.Potassium must never be near the top of range as so dangerous. Quite a lot of food contains Mg. (magnesium) see the web.



Hi Jackie,

I believe its ok for most people who are deficient, which is most people, to supplement with magnesium as any excess can be excreted. It is not easy to test for magnesium as there is only a small amount in the blood and most of it is in the tissues so a blood test is not useful. I have supplemented with magnesium for 5 years and monitor it by the blood pressure level, I needed a lot more at first than I do now. I found that transdermal magnesium oil was good as was epsom salt baths. I have never had any probs at all only benefits, which is the gradual disappearance of the palps and the improvement in blood pressure. I agree with you about supplementing potassium, it could be dangerous, and if someone feels they need potassium it can be added by drinking veg juice, and eating a big bowl of chopped fruit at breakfast and a bowl of home made veg soup for lunch daily. Some people with palps find potassium is needed to control them, some need magnesium, some need iron. If you want to supplement iron you need a ferritin test first as it can be dangerous to have too much iron in the body. This has worked out well for me, I am not suggesting anyone does what I do without researching and satisfying themselves that they will be ok. There is a good article by Dr Mercola linked under this blog if you would like to take a look.


Hi fennel,

Very interesting what you say. My magnesium was exceptionally low, dangerous, I had the blood test. in hospital I was put on a slow magnesium drip, the best way. Then soon after discharge it became dangerously low. After the docs trying various forms which did not help. Even Epsom salts which are recognised as helping, then my nephrologist , head of renal transplant, said that they find the only tablet etc any good was magnesium.oxide . It put my magnesium to normal. I take a lot,have a weekly blood test and it stays normal. I agree measuring the cells for Mg and K+ ( potassium) is the best way but unfortunately no way of measuring what is in the cells for Mg, there is for K+but not usually done ,cost

Best wishes.



here is the article I told you about


Thank you fennel - Dr Mercola is a good site. I have a magnesium spray (which says skin may tingle if you're low - it doesn't) I also have read that bb interferes with thyroid hormone conversion.

I have had Urea & Electrolyte tests too - 'normal'.

So, at the end of the day, it's probably just that I am not treated for hypothyroid. (as my TSH is only 5.12).

I just don't understand why a calcium blocker would help, when calcium is needed! J :D


I believe you should not take beta blockers if you are hypothyroid as it will block the conversion of T4 (levo) into the active T3 that you need to be well.


Fennel, have u read that somewhere? I take beta blockers for high bp and am also hypoT, that could be part of the reason I am still having problems.


Well documented that beta blockers (e.g. propranolol) affect thyroid hormones.

Propranolol decreases plasma T3 and increases plasma rT3 in a dose-dependent manner due to a decreased production rate of T3 and a decreased metabolic clearance rate of rT3, respectively, caused by inhibition of the conversion of T4 into T3 and of rT3 into 3,3'-T2.

It could be impacting but, in broad terms, some of the effect of the beta blockers is likely to have been countered by ending up on a slightly higher dose. Though this might not be the case for you.


I'm on low dose CCB now- but took Beta blockers on and off for a long time.

Last one was atenolol and I stopped this two years ago due to stomach discomfort- and general malaise on BOP meds.

I do wonder, reading this post, if the B Blocks assisted with my drift to UAT.

Thiazide diuretic [for BP] gave me gout -which now needs another lifetime drug to deal with.

(along with Levo, possibly)


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