Thyroid UK

What is the importance of Vit D in thyroid health ?

Hello hypothyroid wise ones

I have recently had another shouting match with my GP, him shouting because he feels threatened ( I think ) me shouting because I know more than he does about my own body ( I know ). Asked him to test for lots of things I have read are important, but got no T3 results and lots of other stuff missing. Vit D came back low 46nmol/L ( 75-200nmol) Free T4 13.0 pmol/L (10.30 - 22.70pmol/L) Serum TSH 3.69 mu/L (0.35-5.50mu/L B12 482 ng/L (211-911ng/L) He wants to retest in another six months b/c that's what the lab's told him to do and doubt he's made a connection with my thyroid, but I know there is one, just not quite what it is.

Weary now. Taking some savings and will be making an appointment to see/ travel to/stay overnight before or afterwards b/c daren't drive >300 miles in one day Dr S in Birmingham. Have a SIL in Belgium and soo tempted to take her up on offer of a six month supply of Cynomel ( GP's given me 75 mcg T4 on which I have felt worse and gained two stones...tried a higher dose under protest ( his ) and heart was racing so came back down ) for next to nothing, but still feel such a junior leaguer and worried as also hypertensive although BP succesfully regulated by meds.

Should I be concerned ? Should I get anything else tested before I see Dr S?

Thanks in advance for responses, off to bed as utterly wiped out. For a change.


6 Replies

It's easy enough to treat your low Vit D and below optimum B12. Why not try hat before your appointment?

Shouting at a Dr is not recommended though - ultimately you need them as much "on side" as possible.


To answer your'e question about the importance of vit D in Thyroid health......It does look like you're vit D is low as you already said and If you are feling tired,this can be down to the low vit D or being under medicated as far as i know.


Hi raps

First of all don't give into your gp, you know your body and don't let him bully you. Your vit d and your b12 are low. Vit d is very low and you should probably start supplementing, b12 should be in the upper third of the rang if you are hypothyroid. You also need to have an iron panel done as this will affect how you process thyroxin. Your FT4 is also on the low side. Most people feel best when that is towards the upper level as well. It could be that you couldn't cope with the increase of thyroxin because of low vitd,b12 and/or iron, so it is a good idea to sort that out before you try to raise it again. If your dr refuses to have FT3 done you could have a home blood test done(pin prick) but the most important thing is how you feel. Dr skinner is lovely and worth seeing but I suggest that you try to sort your vit levels out first. Could take a while.

Good luck



VITAMIN D test: (25-hydroxy vitamin D lab test) measures the level of the hormone vitamin “D”, which plays a role in your immune system and other important actions. 50-80 at the minimum is your goal in the range. Many thyroid patients are low in D due to digestive issues from being undiagnosed or undertreated, plus problems with Celiac or gluten intolerance.

That was from this article.

I'd be tempted to try adding a small dose along with your T4 to see if it makes a difference.

You can skim these suggestions as well.


Thank you all. Issy I do know I shouldn't shout at my GP but when he shouts at me, defensive as I'm effectively questioning his care - it isn't in my nature, ill or well, to just let it go. I am at least an equal stakeholder in my wish for good health and I will not kow tow, which is what he always wants. Last week I asked for a repeat script for thyroxine; he gave me 120 Prozac on the script without my asking. I will be well, with him, without him. One day....I appreciate your support and fear the best thing to do at the moment is struggle on and try to increase my Vit D and B12 levels, I suppose.


Your T4 & TSH was in range, it is therefore unlikely that the labs will check the T3. It is irrelevant whether the doctor asks for this or not, as unfortunately it is the labs discretion as to whether they test this or not.

Make sure you inform your GP that you are taking T3 if you buy your own, (they possibly wont like it, although mine is ok with me buying my own armour), then they can write on the blood request that you are taking T3 so hopefully the labs will test it, but there is no guarantee they will. (remind them to write on that you are taking it when the bloods are drawn)


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