Low Thyroid? How to Conduct a Basal Temperature Test

The Basal Temperature Test is not to be used as a replacement for a proper medical assessment.  Instead it can help you determine whether you may have a thyroid imbalance and a low functioning thyroid gland in particular.  Low thyroid function can cause many symptoms ranging from fatigue to difficulty losing weight.  Check out my blog “Is an Underactive Thyroid Making You Overweight?

Because the thyroid gland reflects the body’s metabolic rate and heat is generated during metabolism, assessing body temperature can give clues regarding the function of the thyroid gland.

1.  Shake down a thermometer until the mercury falls below 95 degrees Fahrenheit if using an older thermometer.  Place it by your bed at night when you retire.

2.  Upon waking, before getting up (yes, even to use the bathroom) place the thermometer under your armpit for 10 minutes.  Digital thermometers may automatically stop before that.  That’s fine.  Try to lay in bed as still as possible during this time.  Rest and close your eyes.  Don’t get up until after the 10 minutes have passed or until a digital thermometer has registered your temperature.

3.  Record the temperature, time, and date.

4.  Conduct the same test for at least three mornings at the same time each day.

Assessing Your Basal Temperature Test

A healthy resting temperature ranges between 97.8 to 98.2 degrees Fahrenheit or 36.6 to 36.8 degrees Celsius.  Natural fluctuations can occur during menstrual cycles.  If you are still menstruating, perform the test on the second, third, and fourth days of the menstrual cycle.

Post-menopausal women or men can conduct the tests any days of the month.

If your temperature is consistently lower than the range indicated above for at least three days, this may be an indication of hypothyroidism.  Conversely, temperatures consistently higher than this may indicate hyperthyroidism but can also suggest a possible infection.  If so, you should see a physician.

If you are working with a naturally-minded physician, be sure to bring the results of your three days of basal temperature tests.  If your doctor wants to conduct blood tests to confirm your results, ask him or her to test for thyroid-stimulating hormone (TSH), free T3, free T4, and thyroid antibodies.  All four tests give a more accurate picture of the health of your thyroid gland than testing solely for TSH like many doctors do.  Actually, many people test normal for their TSH even when they have all the symptoms of hypothyroidism.  Check out my blog “Is an Underactive Thyroid Making You Overweight?” for more information.

Source:  Datis Kharrazian, DHSc, DC, MS, Why Do I Still Have Thyroid Symptoms? (Elephant Printing: 2010).

Subscribe to my free e-magazine World’s Healthiest News to receive monthly health news, tips, recipes and more. Follow me on Twitter @mschoffrocook and Facebook.  Copyright Michelle Schoffro Cook, PhD.

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Siti R.
Siti R.2 years ago

interesting..will try it!

Pat A.
Pat A.2 years ago

For many years I have had to surround myself with five wrapped hot water bottles (they let heat out slowly and keep warm all night) due to my frozen legs (hypothyroid), vividly painful back and joints and so on, AND they help me survive the hypoglycaemic crashes I can suffer at night - can I still take a relevant temperature in the morning when artificially warmed up like that Michelle? If so I will do it....

J.L. A.
JL A.2 years ago

good to know

Tammie Chambers
Tammie Chambers2 years ago

Funny, my temperature has always been 97.6 ish. yet it took doctors until I was 45 to tell me I was Hypothyroid...and thats because I insisted that there was something not quite right and she (dr.) needed to find out what it was.
You HAVE TO be your own advocate with doctors and insurnace these days.

Cheryl B.
Cheryl B.2 years ago


Michaela C.

This is a big problem and I hope they will focus more on that in the future.

Sue Matheson
Sue Matheson2 years ago


Magdika Cecilia Perez

great info

I has hashimotos hypothyroid - and healed myself on a healthy vegan diet

rene davis
rene davis2 years ago

thank you.

Elaine A.
Elaine Al Meqdad2 years ago

I take 1000 IU's Daily of Vitamin D for 5 days a week with 2 days off intervals, for a total of 50,000 IU's weekly. As by the time I got to my Endocrinologist for a thyroid disorder (Hasimoto's syndrome) an auto immune disease, where my thyroid hormones were producing normally, my own anti bodies did not recognize them as "MUCH" needed for the entire body, they would attack the good guys. So basically my own immune system that was working to protect me was actually killing me to the point that I was about 3 weeks away from deaths door. I had NO vitamin D or anything in my body vitamin or mineral wise for that matter. The thyroid folks is the light switch for the entire body...Not the brain, as so many think is. This tiny gland/organ at the base of your throat and shaped as perfectly as a butterfly, weighing only that of an ounce. Is your life line for all internal organs!