Thyroid Hormone Testing
Is your doctor even testing your thyroid?
Your thyroid is a butterfly shaped gland of the endocrine (hormone) system, located in the front of your neck. It’s the main control centre for metabolism of all cells, your thermostat and regulator of myriad of functions in your body.
Because it influences so many functions and systems, the list of symptoms of dysfunctional thyroid is long and very individual, ranging from tiredness and mood issues to gut and weight symptoms.
Main Thyroid Hormones
TSH – thyroid-stimulating hormone
This actually isn’t a thyroid hormone at all as it’s secreted by the pituitary gland in the brain. It tells your thyroid gland to secrete thyroid hormones.
TSH is usually the only marker your doctor will test when they want to check your thyroid function. Do you think checking a pituitary hormone alone will give you a good idea of your thyroid function?
I don’t either!
TSH levels inversely correlate with active thyroid hormone concentrations, i.e. when thyroid hormone level increases, the TSH level decreases and vice versa. So a high TSH level is an indicator that the thyroid is struggling, or you have an underactive thyroid, while a very low TSH level may indicate an overactive thyroid.
Optimally we’d like to see TSH below 2 mIU/l.
T4 – thyroxine
Around 80-90% of the hormones your thyroid produces is T4. It’s mostly an inactive hormone and must be converted to the bioactive T3. This happens mostly in the liver but also in the kidneys and brain.
Some of T4 is also converted to reverse T3, another inactive hormone, and factors such as stress, infections, inflammation, low cofactor availability, toxins, low-calorie diet etc. can increase the conversion into reverse T3.
We can measure both free T4 (FT4) and total T4 (TT4) that includes T4 bound to proteins and unavailable for the body to use. Knowing the FT4 level is more meaningful for us.
Optimally, we’d like to see FT4 between 16-20 pmol/l.
T3 – triiodothyronine
T3 is the bioactive hormone that is responsible for affecting many organs and tissues throughout the body. It’s mostly formed by the conversion from T4 as only a small amount is directly secreted by the thyroid gland.
As with T4, we can measure both FT3 and TT3. To understand whether you body is converting efficiently, we want to measure both FT4 and FT3.
An ideal conversion rate is approximately ⅓ of the T4 being made into T3.
Thyroid Antibodies
To understand if there is any thyroid autoimmune activity going on, it’s also good to check thyroid antibodies when investigating thyroid function.
Thyroid Peroxidase (TPO) & Thyroglobulin (TG) Antibodies
These are the two main thyroid antibodies, and raised levels can indicate autoimmune hypothyroidism, or Hashimoto’s thyroiditis.
Thyroid Stimulating Hormone Receptor Antibodies (TSHR / TRAb) is used to diagnose autoimmune hyperthyroidism, or Graves’ disease.
Factors Affecting Thyroid Function
Thyroid is a very sensitive organ and responds to many lifestyle factors:
- Low nutrient status
- Poor blood sugar balance
- Stress
- Toxins
- Inflammation
- Poor sleep
- Poor gut health
- Overtraining
- Sedentary lifestyle
- Viral infections
- Menopause
- Calorie restriction….
…that can have a big impact on how your thyroid functions and how efficiently your body converts from FT4 to FT3.
How to Support Your Thyroid
Your thyroid is a very nutrient-hungry gland!
To support the production and conversion of thyroid hormones, make sure you have an adequate intake of:
- A generally nutrient-dense diet
- Protein, particularly the amino acid tyrosine
- Vitamins A, C, D, E and B vitamins
- Minerals iodine, iron, zinc, selenium
And also pay attention to:
- Managing stress better
- Prioritising sleep
- Supporting your body well through the menopause
- Regular exercise but avoid overtraining
- Reducing your toxic load and supporting liver function
If you’ve been told your thyroid is “normal” but still feel sluggish, fatigued or have other chronic symptoms, it might be time to dig a little deeper.
Get in touch for a free chat if you’d like to know more about the thyroid testing I offer and learn how to support your thyroid naturally for better energy, mood and metabolism.
My Wellness Check includes a very comprehensive blood test that tests almost 60 biomarkers of health, and covers most of the thyroid markers mentioned above, as well as many co-factors and other related health markers.
I can also run further markers or tailor a blood test panel for you when you work with me.
Book a free chat if you want to know more and discuss your health.