Changing when I take thyroxine for next blood test

[sweepandollie]

I always take my thyroxine at night. What is the best way to go about changing to a morning dose to allow 24 hours before my next blood tests please?

[jimh111]

You can either simply take your tablet at night and then start the next morning or skip the nighttime tablet, due to the long half-life of levothyroxine it will make little difference (less than 5%). Why do you want to allow 24 hours? Four hours is sufficient, the extra hours will only affect fT4 and TSH by a tiny percentage, less than the accuracy of the assay.

[Hidden in reply to jimh111]

Glad of that. Last time I didn't bother to adjust from night time, so it was more than 24 hours

[SlowDragon Administrator]

If testing on a Monday, for example, on Saturday night delay taking Levothyroxine until,Sunday morning. Delay Sunday evening dose Levothyroxine until immediately after blood

You can still go back to taking normal Monday evening dose Levothyroxine as per normal

Many of us find FT4 is very sensitive to when you take Levothyroxine.

Getting bloods tested as early as possible in morning and fasting may help give highest TSH possible

[sweepandollie in reply to SlowDragon]

Thanks. Just what I wanted to know

[jamesal0]

It doesn't matter - your body stores 5-7 day of T4 in your soft tissue and blood. Unless you are taking a T3 product like NDT which will be hanging around and suppress the TSH - it doesn't matter. The other big myth is taking Levo with food/coffee, it makes almost no difference 2-3%. You could go for a hard run and burn up 2-3% of your thyroid stores and they don't warn you about that

James