Hypothyroidism: when the body’s metabolism slows down


Have you had an unexplained weight gain recently? Are you constantly tired and feel you’re moving in slow motion? If that is the case, you may be suffering hypothyroidism. Find out more about this disease in order to be sure!

Hypothyroïdie : quand le corps fonctionne au ralenti

What is the thyroid gland?

The thyroid gland is a tiny butterfly-shaped gland located at the base of the neck. It produces and secretes thyroid hormones that act as messengers that influence several of the body’s functions. For example, they regulate digestion, cardiac rhythm, body temperature, perspiration, the nervous system, the reproductive system, and body weight.

In fact, thyroid hormones determine our basic metabolism. In other words, they influence our cells’ level of activity. When there is an increase in thyroid hormones, our body works faster – this is known as hyperthyroidism. In the case of hypothyroidism, there is a lack of thyroid hormones; as a result, metabolic mechanisms slow down and several unpleasant symptoms appear.


The leading cause of hypothyroidism around the world is iodine deficiency in food – iodine is essential to the development of the thyroid gland. However, this cause is rare in developed countries such as Canada. Hypothyroidism is often due to an auto-immune disorder. This means that the body attacks its own thyroid gland for reasons that are as yet unknown. Other possible causes of hypothyroidism are radiation therapy, certain types of medication, and pregnancy.

Anyone can develop hypothyroidism, though women and seniors are more frequently affected. About 1% of Canadians have the disease. A lack of thyroid hormones can lead to the following symptoms:

  • Constant fatigue
  • Weight gain
  • Swelling in the neck and/or face
  • Dry skin
  • Constipation
  • Hoarseness
  • Brittle fingernails
  • Sensitivity to cold
  • Depressive mood
  • Slowed heart rate
  • Muscle ache or tenderness
  • Hair loss

If you have several of these symptoms, you may be suffering from hypothyroidism. See your physician. A simple blood test can determine if you have this condition.


Fortunately, hypothyroidism is easy to treat. The treatment consists in taking replacement thyroid hormone, known as levothyroxine. To determine the dose that is right for you, you’ll need a blood test before treatment can begin. Later, your dose of levothyroxine will be adjusted in accordance with your symptoms and the results of periodic blood tests. It is important to undergo the blood tests prescribed by your physician to ensure that your levothyroxine dosage is right for your needs.

Generally, levothyroxine is taken for life, since there is no cure for hypothyroidism. The medication must be taken once daily at roughly the same time every day. It may be taken with or without food. It is important to take it at about the same time every day to ensure regular absorption. Since the medication replaces a hormone that is normally present in the body, there are basically no side effects when the dosage is appropriate.


An improvement in hypothyroidism symptoms is generally visible a few weeks into the course of treatment. If symptoms persist after several weeks of taking levothyroxine, it may be that the dose is too low. Speak with your physician, who will adjust the dosage. It is also possible that the dose is too high. See your physician if you have palpitations, increased sweating, jitteriness, insomnia or other unusual symptoms.

Some medication can interact with levothyroxine, including calcium and iron supplements. Before you start taking an over-the-counter medication or natural health product, speak with your pharmacist. He or she is available to answer your questions regarding hypothyroidism and how to treat it.

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