Thyroid function tests show how well your thyroid gland is working. As the thyroid is the master regulator of metabolism, people with weight problems, depression, brain fog, anxiety, and constipation often have impaired thyroid function. Your thyroid hormones are vital for metabolism, heart function, digestion, muscle control, brain development, mood and bone maintenance, to name a few. That makes them pretty important! You may already have been tested and told you were ‘normal’. However, there are three problems with standard thyroid hormone tests: 1. The reference ranges for thyroid hormones are very wide. That means that you could be ‘normal’ even though you are at the lowest end of the scale. Unless you dip under the threshold you won’t get any treatment. This is known as ‘sub-clinical’ hypothyroidism and there is much debate about intervening at this stage, before symptoms progress and worsen. 2. You don't get the whole picture. The standard initial test for thyroid will sometimes only measure TSH (thyroid stimulating hormone) levels. Often T4 is measured though not always in its free form (fT4). It’s really important to know your free T4 and free T3 levels but these won’t necessarily be measured if your TSH is ‘normal’. This testing process only looks at a small part of the Hypothalamus-Pituitary-Thyroid axis and doesn’t take into account what may be happening further down the chain (e.g. T4 converting to T3, the active bioavailable form of thyroid hormone). Nutrient deficiencies can cause issues with the production of hormones, there could be transportation issues, a lack of sensitivity on cell receptors as well as issues with detoxification. All reasons why a wider lens is needed! 3. You might not get to the root cause. If you have low thyroid function, it is vital to know if it is autoimmune related. Around 80% of thyroid disease cases are autoimmune Hashimotos or Graves disease. Autoimmune thyroid conditions have a different aetiology than other thyroid issues, and so require a different protocol of treatment. Many people are just put on Thyroxine, not knowing they have an autoimmune thyroid disorder. As an alternative, a full thyroid hormone blood test panel includes TSH, fT4, fT3, rT3 plus TG and TPO antibodies. That way, if there is a problem you can see where in the chain it’s likely to be occurring and put in place the right nutritional and supplement protocol to address it.