Thyroid UK
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Latest bloods - increase in T3?

Been on T3 1/4 of 25mcg first 4 weeks then 1/2 since and 50mcg levothyroxine. Please can you advise on how much I could increase and how my potassium and magnesium are as I requested these too? Antibodies not back yet but requested also to see if they've been reduced since March last year when I was diagnosed.

TSH 0.17 - GP commented that this was abnormal but expected as under Endo

FT3 5 (3.5-6.5)

FT4 11.3 (10-18)

Magnesium 0.89 (0.7-1)

Potassium 4.1 (3.5-5.3)

I took my levo 24hrs prior to the blood test and T3 12hrs. I also fasted before my blood test.

8 Replies

I'm not an expert at adding T3 but a general comment. When taking T3 in any form then TSH is going to be suppressed and can even be zero. And FT4 can be as low as half way down the range but FT3 should be higher! Was any reason given for taking T3? If conversion is the problem or rather lack of it then it will help if you have Vit D, B12, folate and ferritin tested. We can be low in vitamins and minerals but these need to be optimal to help your general and thyroid health. Many of us take supplements to improve them.


Hi Silverfox7 yes all have been tested and I supplement and am aware my TSH will be suppressed and FT4 low. I'm on T3 as I wasn't converting well and was very sick on levo alone.

What I'm asking is how much T3 should I increase by? Should I take 3/4 of a 25mcg or the whole pill? Should I continue with 50mcg of me vo or reduce this if I take the whole T3 25mcg T3 pill? Thanks


I was really putting it out there if others didn't know that is what happens but I haven't a clue re adding T3


Thanks I've taken 50mcg levo as usual and 25mcg T3. See how I feel if I feel I'm taking too much I'll just reduce my levo :)


50mcg levo and 25mcg T3 - your combined dose is roughly 150mcg of levo which is an average dose.


Does it make a difference that I was over medicated on 100mcg of levo as FT4 was high but I wasn't converting? Is it worth just reducing my levo dose to 25mcg or cut it out completely?


MissFG I am self medicating with T3 added to my prescribed Levo, but don't have the back up of GP or Endo.

Personally I would have gone to 18.75mcg T3 with your 50mcg Levo and monitored that for a few weeks.

With your current results, personally I would not reduce Levo.

When I first started adding T3 I was very overmedicated with Levo, I was on 187.5mcg and my FT4 was 29.27 (12-22), I reduced to 175mcg and FT4 was 28.59 (12-22).

I am currently on 75mcg Levo​ and 31.25mcg T3, and depending on whether T3 is equivalent to 3 x or 4x Levo (I've seen both mentioned) then I'm taking the equivalent of 186.75 or 200mcg. I'm still tweaking my doses a year after starting T3, I haven't found the right combination yet.

I wouldn't worry about what the equivalent is, go by how you feel and keep your FT3 in range

1 like

Ok thanks I'll try 3/4 of 25mcg T3 for 4 weeks til my next bloods and see how I go :)


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