Thyroid UK
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Thyroid function test results - doc forgot to mention vit d deficiency

Morning! Hope you are all well.

I posted on here a couple of months ago regarding my long list of symptoms and was asked to get my blood results.

Very interestingly I got a test done, went to see the doctor for my thyroid results (which were deemed normal) but explained my symptoms, palpitations, tiredness, coldness, nausea, low mood, brain fog & constipation) and he suggested even though my results were ok I clearly needed some extra thyroxine so upped my dose from 100mg to 125mg and I have to return in 3 months. I was pretty happy with this as I felt I was being listened to not my results, especially after only 2 weeks of taking the new dose felt better.

The point of this waffling is this, I went back to the docs on Friday with an unrelated issue and the doctor asked if I was given any vit D supplements last time as my levels are deemed abnormal. It seems the original doctor forgot..... My results are below but I'm a little concerned now as can't low vit d stop me absorbing thyroxine and surely now I'm taking this supplement and my increased level of thyroxine I could be over medicated?

Tsh - 0.31miu/l

T4 - 15.1 pmol/l

B12 - 305ng/l

Folate - 6.4ug/l

D2 + D3 - 40nmol/l

Thanks for listening!


2 Replies

This is one of the reasons why I always ask for a print out of my results. As far as I know, good vit D levels are important for disease prevention and reduction of inflammation. I don't think it will effect your levo absorption, but someone with more knowledge will advise you better I am sure.


Asnm78, low vitD doesn't affect absorption of thyroxine but good levels of vitD aid T4 to T3 conversion. Your TSH 0.31 is low on 100mcg but FT4 15.1 is quite low too (I'm assuming the top of the range is 22 as you haven't posted ranges) and a dose increase to 125mcg will improve FT4 without over medicating you.

How much vitD3 are you prescribed? Make sure to take it 4 hours away from Levothyroxine.

B12 305 is low. Supplement 1,000mcg methylcobalmin sublingual lozenges, patches or spray and take a B Complex vitamin which will keep the other B vitamins balanced and improve your folate.


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