How long for t4 to rise after a med increase?

[Eshep]

I know that you must wait 6-8 weeks after an increase in t4 meds for the tsh to stabilize. But about how long after a t4 med increase will your t4 levels begin to rise?

[greygoose]

It's not really about your TSH - although doctors think it is! It's about giving that T4 time to convert into FT3 - although they rarely test it.

I don't know if anybody has ever done any research into how long it takes for T4 to rise, but I would imagine it would be a slow increase, given that you're taking it daily, and not all in one lump. Every day, it would get a little higher, I would imagine.

[Dee1 in reply to greygoose]

That is fascinating. I haven't thought before about the time it takes for the T4 to convert into T3. Is there any info you can direct me to on this? Many thanks.

[greygoose in reply to Dee1]

Sorry, no. It's just one of those things you pick up along the way.

[Dee1]

Thank you. It is good to know anyway what the reasoning behind the 6 week wait is.

[silverfox7]

I read that any dose increase gradually builds up in your body and it's tobdo with half life. So itstakes 6 weeks for the new dose to build up to its maximum in your body.