Should I not take my T3 before blood test? - Thyroid UK

Thyroid UK
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Should I not take my T3 before blood test?


I’m currently taking 75mcgs T3 around 7am each morning. I want to monitor for myself whether I need to increase/ lower dosage. The results won’t be seen by a GP or endo. My question is should I test at any particular time of the day ... and should I take the T3 as per normal?

Many thanks for reading this and any advice.


3 Replies

FT3 fluctuates slightly throughout the day, and is highest in the morning. However, if you take your T3 in the 12 hours before the test, all you will be testing is the dose you just took, not the normal circulating level in the blood. So, no, don't take your T3 as usual. :)

Thanks Greygoose, that’s really helpful, will do! x

You're welcome. :)

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