Thyroid UK

T3 side effects?

Hi I'm on my 4th day if taking T3 and I've severe palpitations and tremors/shaking is this normal at first?

I was over medicated on 100mcg levo so reduced to 75 and just taking 1/4 of 25mcg of T3. Couldn't get it from my Endo so bought it myself and told my GP I was going to self medicate, he panicked and said he couldn't support me but wanted to help me and would prescribe it with permission from my Endo. My Endo saw me straight away and agreed to look after me and as I'd bought them to start taking my T3. He suggested 1/2 pill but I said I was going to do 1/4 and he said that was very sensible and agreed but not to increase after 2 weeks but rather in 4 once we had bloods done. Luckily I have a supportive Endo but I know it was due to the cost. Surprised he's let me take my own though? TBH I always expect side effects when I change my levo dose but do feel a little strange, couldn't sleep last night either as palpatations were so bad in my head and chest. Any advice?

7 Replies

You say you were overmedicated on 100mcg of levo and reduced to 75mcg. Was it the blood test that indicated your were on too much, or did you have sensations of being on too much.

Now you have added 1/4 T3 (I am assuming it's a 25mcg and 1/4 would be around 25mcg levo) so that would raise you back up to around 100mcg.

Maybe you might settle down in a couple of days. Did you take your pulse/temp before adding T3 as that may be an indicator of too much. I know everyone is different but I found the opposite when adding 10mcg of T3, everything calmed down.

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Yes it was a blood test. My TSH was 0.01 and FT4 27 and FT3 just creeped up to 5.6. My bloods in December were out of range too but not as much. Endo wanted to reduce my levo from 100 to 75 but then I couldn't get out of bed and all I wanted to do on 75 or 100 was sleep.

I was thinking maybe I should try 50mcg if levo and 1/4 of 25mcg T3 but it's a bigger drop and Endo suggested 75? I'm hoping I might settle down as it's early days but not sure how long I should wait before adjusting something and if I do should it just be taking my levo down to 50?


The TSH shouldn't be used to adjust medications but that's what they've been taught. Some need a suppressed TSH to feel well. I'd give your new regime a bit more time as at times we need to be steady instead of chop/changes and we might never reach a 'good' dose which makes us feel well.


It was based on my FT4 which was increasing and 27 when top end of range was 22 so I was quite a bit over


Did you allow a gap of about 24 hours between your last dose of hormones and the test and take it afterwards?


Yes and I don't eat or drink prior the bloods either. It's been really difficult getting it under control so let's hope T3 is the answer as I've been told armour and NDT are expensive so doubt I'll be able to afford either of them


I hope adding T3 works for you. I found a big difference when adding some. We should be allowed to try various combinations - so that we are not constantly ill and allowed to find a combo which makes us feel well again.


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