Many patients believe that their thyroid is “fine”, as when it was tested the results were “normal”. However what most clients don’t know is that the routine test for thyroid function doesn’t actually involve testing your thyroid hormones at all, but instead gauges your thyroid function by testing a pituitary hormone called TSH (or Thyroid Stimulating Hormone).
TSH (or Thyroid Stimulating Hormone) is the hormone released by your pituitary gland to stimulate thyroid gland hormone production. When stimulated by TSH, the thyroid gland produces T4 (inactive thyroid hormone) which is then converted to T3 (the active hormone) in the liver. T3 is involved in stimulating a vast array of processes throughout the body, including your processes regulating your metabolism, energy and mental function.
If your TSH levels are outside of the reference range than further investigations are conducted, however what if your results fall into the upper or lower end of the reference range? This can mean that your thyroid function is sub-optimal, but you will be told it is “normal”.
As a general overview abnormal TSH levels indicate the following:
- High TSH levels: May indicate underactive thyroid. Your thyroid needs more TSH stimulation by the pituitary gland to do its job. High TSH levels are generally seen in hypothyroidism or Hashimoto’s Thyroiditis.
- Low TSH levels: May indicate overactive thyroid. Your thyroid requires less TSH stimulation by your pituitary gland. Low TSH levels are usually seen (although not always) in Hyperthyroidism or Grave’s Disease.
These examples are generalisations, as sometimes TSH can be high when thyroid function is overactive and visa versa. That is why comprehensive testing is essential if you have symptoms of possible thyroid imbalance.