Yes, Gcart , FT4 will reduce when you add T3, as will TSH.
There is scope to increase your T3, as advised in your previous post a few days ago, just keep an eye on your FT3 as it needs to be kept in range.
Personally I don't think you need to increase your Levo as your original FT4 result on 75mcg was 22.4. (12.0. 22.0), it just that the T4 wasn't converting to T3 well enough.
Just increase the T3 a little for now, slowly and gradually is the way to go with T3, see how it goes and how you feel.
Your TSH is a bit low as well, but I have read that running it low is ok you might have to consider reducing the T4 in the future T3 is 4 times more effective than T4.
I agree with Susie and give any increase of T3 to work for a week or so to feel the result. You may even end up being one of those who do better with T3 only. When T4, thyroxine, doesn't convert to FT3, it will become REVERSE T3.
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