Thyroid UK
82,834 members97,865 posts

Studies which support need for T3 testing


I was diagnosed as being hypothyroid a couple of years ago and have been taking increasing doses of Levothyroxin since then (currently on 75mg).

My health hasn't been great with lot's of hypothyroid symptoms even with TSH test of 1.5.

A GP I saw refused to refer me to see an endocrinologist because she considered herself to be "the expert"! She also told me, when I asked about T3 testing that it was very rare for people not to be able to convert T4 into T3.

Having done a bit of reading I understand that this isn't necessarily true so I went back and saw a different GP who was much better. She agreed to test me for the Hashimotos antibodies as well as a range of vitamins and minerals. She also agreed to test me for T3, however, when she tried to order the test the system wouldn't let he do it because my T4 and TSH had come back as normal and they don't have any way to order tests other than through the system.

I am obviously not very happy that the GP's clinical decision to test me for T3 is being overridden by bureaucracy so I am writing to the practice manager to complain.

I am aware of the NHS's stance on T3 testing so I would like to be able to reference some recent research which shows the NHS guidelines are questionable, I have had a look on line and have not been able to find much. If anyone knows of any research that could support my argument, please could you share?

Many thanks,


2 Replies

First I would say that your dose of 75mcg is very small and I would think it might contribute to you feeling unwell and with clinical symptoms.

Most of us feel much better when our TSH is 1 or lower and some suppressed. I will give you a couple of links which state that T3 is helpful. Now, the British Thyroid Association, in their updated guidelines say that T3 might be added to levo.

This is a link and go to the end column of page 79 and first column on top left-hand column where you will see the recommended portions of T4/T3.


If your GP is agreeable, get them to write that you are taking T3 on the lab form. Mine does this to ensure it's tested (although I also have a very low TSH level, which also helps).


You may also like...