Thyroid UK
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Latest samples show low T4, T3 and low Vit D How bad is this?

Vit D is 16.5 (20-50)

FT4 1.08 (0.8-1.75)

FT3 2.73 (2.3-4.2)

TSH 0.921 (0.47-4.64) which is strange to be normal as TSH production is very weak and was suppressed in the last year with normal T3/T4 (my doctor and I think pituitary dysfunction).

I felt very bad and my symptoms got worse. The only thing I changed is taking my T4 medications afternoon between lunch and dinner and stopped supplanting Vit D.

7 Replies

Food can interfere with the uptake of levo so maybe if you didn't leave a sufficient gap between lunch and levo, it might have affected your uptake.

Our stomach has to be empty to accept thyroid hormones and allow them to be dignested. If you've eaten it's about three hours after that you can take levo plus another hour to allow it to be digested.

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Shaws, You are right. I usually put 1-2 hours min. before taking Levo, it seems more time is needed making first thing in the morning the best time. I do always have at least an hour to before eating. Now I will be more careful this is very serious.


If you get out of bed during the night you can always take it then and there's definitely an empty stomach then :)



Make sure you take thyroid medication 1 hour before food and drink or 2 hours after food and drink.

FT4 and FT3 are a little low in range so a dose increase will improve both.

VitD is very low. You should resume supplementing D3 until vitD is around 50ng/ml. Take vitamin D 4 hours away from Levothyroxine.


I am not a medical professional and this information is not intended to be a substitute for medical guidance from your own doctor. Please check with your personal physician before applying any of these suggestions.

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TSH is irrelevant when on any sort of replacement.


I know but in my case it is little bit different; my TSH was suppressed even before replacement. Now it is not when my T4/T3 went lower.


Clutter, I expected you to say you are very low, I'm only 30% of the normal range for FT3/FT4.

I'm resuming Vit D ... I take alfacalcidol?


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