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Thyroid UK
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TSH 3.10 (0.3 - 5.0)

Serum Free T4 level 16.9 (12.0 - 22.0)

Serum free triiodothyronine level 5.3 (3.1 - 6.8)

Total Vitamin D. 75nmol/L

Vitamin B12. 285 (200.0 - 960.0)

Ferritin. 43 (15.0 - 350.0)

Folate 5.4 (3.0 - 18.0)

(These were results based on 62.5mg Levothyroxine I am now on 75mg.)

Desperate to get rid of my brain fog / cognitive problems. Any advice most appreciated :)

4 Replies

Are you taking thyroid medication?

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75mg levothyroxine


Looking at your recent previous post you only just put dose up to 75mcgs 7 days ago

When was this blood test done?

Testing needs to be six weeks minimum after any dose change and to be on constant dose.

Your ferritin is still too low, it needs to be at least 70.

B12 too low, sublingual B12 lozenges can improve this and recommended to also take vitamin B complex as well.

But when taking vitamin B complex, or any supplements containing biotin, remember to stop these 3-5 days before any blood tests, as biotin can falsely affect test results



Vitamin D - 75nmol is ok, a bit higher may be better


Thankyou for your reply and the links :)

Yes your right my dose only went up to 75 a week ago and these tests were done five days ago. Reason being I was being tested for a previous increase from 50mg to 62.5mg. I went up again after 3 weeks instead of six because the 62.5 wasn't enough to help my symptoms ease. The 75 has taken the edge off but I'm still not out of the woods so to speak!

Will check out the links , bought an excellent B complex today. And a much better D too. Going to be working on my iron levels now as well. My previous vitamin D was the smallest dose you could buy!

Thanks again :) I'm going to do all I can to improve these results! Feeling positive x

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