Log in
Thyroid UK
91,872 members106,137 posts

Hypothyroid - vitamin levels query

Hi, I was diagnosed hypothyroid last month with TSH level 80 and free T4 3.4. I was put on 100mg Levo. I did a private blood test last week to look at some key vitamin levels. My TSH had gone down to 20 and my T4 is now in range. However my vitamin levels looked low. Could somebody please advise what/how much I should be supplementing to sort this out? Levels: active b12, 47. 5 (25 - 165) and vitamin d, 42.5 (50 - 200). Iron levels were good. Many thanks in advance for your help

4 Replies

You should wait6-8 weeks between tests at which point you may need more levothyroxine to bring TSH to close to 1 or below.

You should also test antibodies.

You are best looking at Seaside Susies responses to folk on vitamins although I think she directs folk to the pernicious anaemia community for active B12,comments.



Was dose increased beyond 100mcg? TSH 20 is still high. You will be optimally dosed when TSH is 0.3 - 1.0 with FT4 in the upper range.

Active B12 >35 is very unlikely to be deficient so 47.5 is fine.

VitD 42.5 is insufficient. Your GP should refer to local guidelines or the cks.nice.org.uk/vitamin-d-d... Do NOT accept a prescription for 800iu which is a maintenance dose prescribed after vitD is replete >75. Vitamin D should be taken 4 hours away from Levothyroxine.

Alternatively, you can buy vitamin D3 without prescription. I suggest 10,000iu daily for 6 weeks then reduce to 5,000iu daily and retest late March/April. If you buy on Amazon please use the affiliate link healthunlocked.com/thyroidu...


Thank you so much for your reply, that's really helpful. My GP is taking my bloods again next month to check levels and amend levothyroxine dose. These were private blood tests I had done just to check my vitamin levels were optimal. I will start supplementing vitamin D. Many thanks again for the help



Arrange an early morning and fasting (water only) blood draw when TSH is highest, and take Levothyroxine after your blood draw.

1 like

You may also like...