Vitamin D - in range but should I supplement?

Hi, I'm on 100mcg of thyroxine and my GP has agreed to give me a trial increase to 125mcg. My thyroid results are:

tsh 0.19 (0.27-4.2)

FT4 16.17 (12-23)

FT3 4.9 (3.1 - 6.8)

I have also now obtained a copy of my b12 etc results from last September. All are in range but vitamin D is at the low end, is it beneficial to supplement? I'm already taking vitamin B12 as I thought this may be low but it isn't (these results are before I started taking a supplement).

Serum vitamin B12 400 ng/L (180-900)

Serum vitamin D 83 n mol/L (50-250)

Serum folate 13.4 ug/L (4.6-20)

Any advice greatly appreciated.


14 Replies

  • Your B12 needs to be above 600 for you to feel the full benefit, nearer 700 would be even better.

    Your vitD could also do with a boost if your calcium levels are in range. Have you ever had your calcium levels checked. The more vitD you take the more calcium your body will make and if you are taking a vitamin d suppliment with calcium (which a lot of them are) you could be storing up trouble for yourself as this might lead to painful gallstones. If I were you I would ask for a calcium test before supplimenting and then, depending on the result, find one without calcium added.

    Moggie x

  • Thanks moggie, I had a whole range of tests last sept, the calcium ones are;

    Alkaline phosphate level 48 u/L (30-130)

    Serum calcium level 2.36 (2-2.6)

    Corrected serum calcium level 2.32 mol/L (2.2-2.55)

    Appreciate your advice, I have a better understanding of thyroid results now but I'm clueless with the rest!

  • summer, they are combining vitamin D3 with K2 to handle the calcium issue. Read up on that. D is so important for infections and even cancer and if you can't get 15 minutes of sunshine every day you are probably losing.

  • Thanks Heloise, I went to the nutri centre this morning and have purchased a spray vitamin D. It's a 1000 IU per spray. It doesn't mentioned calcium. I spoke to my doctor and he said to take a 1000 IU dose and he'll check my levels when he does the thyroid blood tests in 6 weeks.

    I'm goin to try to make sure I get outside a little more too - I can the train and tube to work and then sit in the office all day!


  • I think that is wise, summer. K2 assists calcium to develop in bones and teeth rather than arteries so with a high dose of D3 it's probably more important. Your 1000 i.u. is barely above minimum daily requirement in the U.S. I take 10,000 i.u. myself since I have been very low for years and this barely brings it up. You are taking D3 and NOT D2, hopefully. Even with tanning, I couldn't get levels up.

  • Hi Heloise, it is D3. I don't want to overload but at the same time I'm desperate to do all I can to help myself. Hopefully this along with my thyroxine increase will help. The spray taste very nice - it's mint favoured!

    Thanks for all your advice

  • Are you due to see your GP in the near future - if so I would ask his/her advice. Tell him/her that you want to suppliment your VitD as you feel it is a bit low and ask if they would recommend a suppliment with or without calcium BUT make sure they are looking at your calcium levels when answering. I have had my GP and Endo tell me that I need to be supplimenting vitd with calcium and then when I questioned this they then, and only then, looked at my results, saw my calcium levels where right at the top of the range and did a double take and said "no calcium". If you make it plain to your GP that you know about the vitD/calcium connection you should be o.k.

    Hope this helps

    Moggie x

  • Thanks moggie, that's very helpful. I don't want to take tablets that may not help or even cause problems but at the same time I want to get back to 'normal' as soon as I can. Really appreciate your help, I've read up on vitamin D and was still confused but you've explained things perfectly :-)

    Thanks x

  • Here is a very useful link re VitD from Barts Hosp in London. It helps explain how your body uses Vitd and also what foods to eat. See what you think.

    Moggie x

  • That's brilliant, thanks so much. I've read loads of stuff but didn't come across anything as informative as that paper. I'll ask he doctor when. See him again next week. Thanks so much x

  • p.s. and its also a very sensible attitude you have regarding not taking tablets/suppliments until you have checked out the possible complications and implications.

    Moggie x

  • Hi I would definitely take some vit D as hormonal and will help the thyroid. However, only if you calcium is well in range and not at the very top. Calcium must always be in range regardless of other things and vit D does put up the calcium.

    Best wishes,


  • Thanks Jackie, I've bought some today and my doctor has said he will test the levels again at my next thyroid function test.


  • Hi Remember it does take 3 months to reach optimum levels of D for your blood test.


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