Thyroid Function Test and understanding the hormones involved

Thyroid Function Test and understanding the hormones involved

If you have missed the previous 2 blog posts on What is your Thyroid and why is it so important? and understanding Hashimoto’s  a little bit better click on the links and have a read of them first.

If, from reading the previous blog posts and watching my videos on Instagram @somawellnessdoula you have had a light bulb moment of thinking “hhmm this is sounding all too familiar” I would strongly suggest asking your GP to test the function of your thyroid.

Getting your thyroid checked is a simple blood test that your GP can take and they might palpate around your neck to check for a goiter, I would also suggest write down your list of symptoms regardless of how crazy they may seem or unrelated, jot them down and your GP is getting a bigger overview of what is going on along with how you are feeling physically, mentally and emotionally.

The standard thyroid function test in Ireland checks your TSH and T4 hormone levels. TSH is your Thyroid Stimulating Hormone which is produced by the pituitary gland and basically tells the thyroid gland how much or little hormones to make. T4 is the Thyroxine hormone and is one of the hormones produced by the thyroid gland. The other hormones produced by the thyroid gland is T3 which is known as Triiodothyronine. (and not forgetting the hormone Calcitonin which is thought to play a role in regulating calcium levels in the body).


It is really important that we dig a little deeper and understand the workings of the hormones a little better. You might have a lot of the symptoms of thyroid problems but yet your TSH and T4 levels are coming back within range so your doctor might say something along the lines of “all is fine with your thyroid, no need to worry!!” But if you haven’t noticed T3 is not routinely tested for in the thyroid function test. Which is disappointing and frustrating as T3 is the active hormone that our body uses.

T3 and T4 are collectively known as the thyroid hormones. T4 is a relatively inactive hormone and T3 is the active hormone, in other words it is the T3 hormone that our body uses as it is biologically active and influences the activity of all the cells and tissues of your body. Approximately 20% of T3 is produced by the thyroid gland and the remaining T3 comes from T4 being converted to T3 by the cells and tissues of the body.

So if you have had “normal” blood results come back and your still experiencing symptoms and nothing else is showing up in your blood work I would suggest requesting to test for T3 levels along with your thyroid antibody test. It is important to note that some people can have normal thyroid levels but their body can still be producing antibodies.

FYI from speaking with my Endocrinologist she advised me that in relation to TSH there is a normal reference range, from 0.2 to 5, however, the optimal range is 0.2 – 2.5 and for anyone trying to conceive or having fertility issues and you have been told that you are borderline underactive or that your are underactive you need to be making sure that your TSH level is at the optimal level and not just the normal level. This is a conversation I would strongly encourage you to have with your GP if it relates to you. If your not happy with their answer always ask for a second opinion and do your research.

My final piece of advice and this goes for all blood tests that you get done, is to always ask for a print out of your blood results and the ranges. It is so important to become an active participant in your own health and wellness and ask your care provider questions and get clarification if you need to.

In my own personal story I was nervous, doubting myself and unsure of “questioning” a medical professional to do extra thyroid tests, it took alot of courage to ask for the tests but I am so glad that I did. My GP was the one who initially referred me to the website and from there I learnt so much, it is a great place to start with and build your knowledge. There is also an Irish Facebook group called Thyroid Ireland.   and also some really good information on Dr. Neville Wilson website

I hope you found the information helpful and above all it sparked something in you to begin your path to optimal health and wellness.


Sources for this blog post came from:

Disclaimer: I am not medically trained so please take the information provided here as educational purpose. I strongly recommend to go and talk to your GP, Doctor, Endocrinologist or medical profession. Start the conversation and get involved in your health and wellness.


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