A blood test reading of high thyroid stimulating hormone (TSH ) levels is generally indicative of an underactive thyroid gland most probably due to thyroid dysfunction (thyroiditis, Hashimotos Disease, thyroid removal).

TSH is produced by the pituitary gland and this hormone signals the thyroid gland to make and release the hormones thyroxine (T4) and triiodothyronine (T3). The TSH levels are high due to a feedback system that reads the T3 and T4 levels as being low and tells the pituitary gland to produce more TSH due to a deficiency of thyroid hormones.


The best way to determine the activity of the thyroid is to test the basal metabolic temperature each morning for three days with a thermometer, if it is low each day then this indicates low thyroid function.

The following describes how to test basal metabolic rate:
Place the thermometer by the bedside before going to sleep. Make sure it ready to use.

Immediately on waking, place the thermometer under the armpit for a full 10 minutes. It is important to remain still. Read and record the temperature.

Do this for three or four consecutive mornings, preferably at the same time of day.

Menstruating women must perform the test on the second, third and fourth day of menstruation.

Interpreting the Test

Normal body temperature is 36.7 C + or – 0.2 C ( 97.6 F – 98.2 F).

Low basal body temperatures may reflect sub-clinical or fully developed hypothyroidism

High body temperatures may point to hyperthyroidism.

Alcohol and diet can affect metabolism and therefore the readings so choose a time when a normal routine is being followed