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Thyroid UK
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Should I revert back to morning T4 dosing now?


So, 6 weeks after having tried taking T4 (100mcg) at bed time instead of first thing, I got my bloods done. I was shocked to say the least.

Latest results are:

TSH: 0.06 (0.27 - 4.20)

Free T4: 17.8 (12 -22)

Total T4: 92.6 (59 - 154)

Free T3: 3.44 (3.10 - 6.80)

My T3 is now the lowest it's even been. Before changing my dosing to night time, my results were:

TSH: 0.01

Free T4: 16.2

Free T3: 4.6

These were done last November.

When taking my meds at bed time, I was leaving 3 hours after eating before taking them.

Would people agree I should revert to morning dosing? It seems I don't convert well to T3 when taking my meds at night.

Has this happened to anyone else? I thought night time was meant to be better for most people.


7 Replies


Research shows that bedtime dosing reduces TSH more than daytime dosing. Perhaps your TSH would have been higher and FT3 lower if you had continued morning dosing? The only way to tell is to try it. If it makes no difference or thyroid levels worsen you can always switch back to nighttime dosing.


Thanks Clutter. The thing is, I've been taking T4 for well over 10 years before I decided to change to night time. My results hadn't changed in the last year at my 100mcg dose when taken in the morning. The last 6 weeks has been my first experiment with night time dosing. I can't believe the difference it has made, and not in a good way. Does it make sense that myT4 is higher and my T3 is lower? Is that less T4 converting?



Your FT4 is higher which would normally mean more conversion to T3.


As you take a bedtime dose, did you miss this dose the night before the blood test and take after it? If not the results may be skewed. Was your test a fasting one (you can drink water). You can also take bedtime dose as usual the same day.


I did not take my meds the night before. I took them the morning after the test (so test was 36 hours after last meds). I also fasted for 12 hours before testing. I am so confused by the results but can't think of anything that would have skewed them.


The major question is 'how are you feeling'? This link from a doctor who was an Adviser to Thyroiduk.org.uk before his death stated and may be helpful:-


1 like

That is an extremely interesting and informative read thank you. I am inclined to think my low T3 result is accurate as I feel tired and lethargic, like my body is shutting down. And my menstrual cycles have become more drawn out. Plus my basal temperatures are lower. I just don't get why my T4 is higher than before but T3 so much lower... I'll see what the endo says. Thank you for your help.


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