Thyroid UK
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T3 & T4

I started adding t3 to my t4 a few weeks ago, starting with 1/4 of 25mcg tablet. I increased to 1/4 tablet twice a day, reducing levo from 125 to 100mcg. The first couple of days on the increased t3 I actually felt great (bit of a headache but I do with every increase of meds), but it it was short lived as I feel pretty rubbish again, just when I thought I was getting somewhere 😞

6 Replies

Pinklady, go back to 6.25mcg. The higher dose T3 will wash out in 3 or 4 days, faster if you stop T3 for a couple of days. Your results from a month ago had good FT3. Not everyone feels well with FT3 at the top of range.

Free T4 21.24 (12 - 22)

Free T3 4.74 (3.1 - 6.8)

TSH L 0.23 (0.27 - 4.20)

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Thanks I didn't even think to do that, on the 6.25mcg I didn't really feel much different, however the first 2 days of 12.5mcg I felt great and just assumed it was because I had more. Perhaps it was just delayed benefit of the 6.25mcg.

Presumably if dropping to 6.25mcg I should increase my levo back to 125mcg?


No pinklady,

You are only stopping the T3 to allow the T3 to wash out of your system before starting again 2 days later on a starting dose.

Leave T4 at 100mcg and introduce T3 more slowly to allow your body acclimatisation time.

Yes you will be a little short on total amount of hormone but it will balance out over the days. Increasing your T4 now would not have any effect for 7 days anyway.

Good luck,



Thank you, I don't know what I'd do without this support group, I don't have any clue lol


Pinklady, no, you appeared to be optimally dosed on 125mcg so it was right to reduce to 100mcg when adding 6.25mcg T3, which is equivalent to 18.75mcg T4, and roughly an equivalent dose to the 25mcg you reduced.

4 weeks wasn't long to give T3 to work, it takes 6 weeks to metabolise and feel the full impact. Your FT3 was good so you won't notice a dramatic difference as someone with low T3 can when adding T3.

If you decide to increase T3 again, reduce T4 to 87.50mcg for a week first.

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Ok that makes sense, thank you 😀


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