Thyroid UK

T3 Levels

Hello, I am new to the site. I've been struggling immensely with thyroid related symptoms since I was diagnosed 2 and a half years ago. In that time my doctors have increased my levothyroxine dosage by 25mcg each time and I have now been on 100mcg for a year. I have never felt well despite any increases (I suffer hypothyroid and chronic thyroiditis) and after years of research I am coming to the idea that my T3 levels are the problem. My GP will not test me for this so I am seeking private care instead. I wonder if anyone has also experienced this and if you could shed any light or hope? Thanks, Kristy x

6 Replies

Welcome to the site. Have you looked at the ThyroidUK website. There's loads of useful info there.

You might find it useful to get a set of thyroid blood tests done from such as Blue Horizon or Genova as part of your research. It's also important to check for vitamin and mineral deficiencies - some of these are important for conversion from T4 to T3.

Do post your latest blood tests with ranges for others to look at and comment.

Keep fighting.


Thank you so much. I will be back with blood test results x


Firstly get an FT3 blood test to see if you are converting enough of the T4.

Blue horizon do a home test finger prick test which is simple and reliable. This may help evaluate things a little better.

Post them on here as soon as you get them.


Thank you so much. X


Hi Klm, this website is very helpful. These are the tests and results you need to strive for when you are hypo. There are some European requirements at the end.


My experience is this. On T4-only, I could only get my TSH down to 4.0 at about 88mcg; I could not feel well. If I attempted to go higher, my body would rebel: I would get anxious, jumpy, and generally non-functional. So I went on T3-only for a year while I was working on adrenal issues, and felt pretty good. I am now back on T3+T4=15+75 mcg, and I feel great! Assuming you are taking care of nutritional issues, and you are monitoring your thyroid antibodies and hopefully getting them down via dietary changes like removing gluten and adding probiotics and enzymes to help your gut, then it is highly likely your body misses the T3 your thyroid used to make, and is not able to do sufficient T4->T3 conversion. It is unfortunate that you have a bull-headed doctor who cannot tolerate the fact that some patients cannot do T4->T3 conversion well. My advice to you is, assuming you can afford it, purchase T3 off the web and treat yourself. You can estimate your T4-only requirement by using Abbott's T4 full replacement guideline of 1.7mcg/kg body weight, then backing off T4 and adding T3 in using a T3 power factor of 3-4. You could also try NDT, if it is easier/less expensive to do that.

1 like

You may also like...