Ask A Doctor

Ask a Doctor: Underactive Thyroid

BY Dr. Ann Corson TIMEApril 7, 2014 PRINT

What body systems does the thyroid affect?

Dr. Ann Corson: The thyroid hormone acts on all tissues of the body. Virtually every aspect of cell growth and differentiation, the utilization of vitamins, minerals, amino acids, carbohydrate and lipid metabolism, and other hormones are regulated to some extent by the thyroid hormone. Nutritional deficiencies and chronic illnesses can affect the production of the thyroid hormone.

What is the best way to tell if you have an underactive thyroid, or hypothyroidism?

Dr. Corson: One simple assessment of thyroid function is the axillary basal body temperature. Check the armpit temperature for 10 minutes upon awakening before getting out of bed. Average the temperature over 10 days. Normal is 97.6 to 98.2 degrees. An average at or below 97.0 degrees is suggestive of hypothyroidism.

Symptoms of hypothyroidism include tiredness, lethargy, sleepiness, constipation, slowing of mental function, difficulty in memory recall, slowed speech, decreased initiative, depression, headaches, slowing of motor activity and reflexes, and muscles stiffness or aching with swelling after exercise.

Additional symptoms include weight gain with inability to lose weight, cold intolerance, low body temperature, abnormal menses (often heavier flow), infertility, hair loss, dry and brittle nails, dry skin, loss of the lateral [outside] third of the eyebrows, hoarseness of the voice, and a tendency to suffer from recurrent infections.

How reliable are thyroid lab tests?

Dr. Corson: Although lab testing keeps improving, there is no true “gold standard” test of thyroid function. Many patients with real thyroid problems have normal blood tests. Lab tests should always be evaluated in the context of the patient’s symptoms and physical findings.

What can we read to learn more about thyroid conditions?

Dr. Corson: “Hypothyroidism: The Unsuspected Illness,” by Broda O. Barnes, M.D., and Lawrence Galton, and “Why Do I Still Have Thyroid Symptoms When My Lab Tests Are Normal?” by Datis Kharrazian, D.H.Sc., D.C., M.S.

Dr. Ann Corson is a board-certified family medicine and integrative holistic-medicine doctor who specializes in treating chronically ill patients.

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Image of male thymus via Shutterstock 

Epoch Health articles are for informational purposes and are not a substitute for individualized medical advice. Please consult a trusted professional for personal medical advice, diagnoses, and treatment. Have a question? Email us at

Dr. Corson obtained her MD degree at the University of Pennsylvania School of Medicine in Philadelphia, PA in 1982 and is board certified in Family Medicine and Integrative Holistic Medicine. Her solo practice in Philadelphia, PA is devoted full time to the treatment of patients suffering from all forms of chronic disease. In 2008, Dr. Corson joined Doctors Against Forced Organ Harvesting (DAFOH) to help raise awareness of China’s live forced organ harvesting of innocent prisoners of conscience, primarily Falun Gong practitioners. Since 2016, she has been editor-in-chief of DAFOH’s newsletter.
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