Thyroid Disorders in Canada: Symptoms, Testing, and Treatment

Thyroid disorders affect approximately 1 in 20 Canadians, with women being more commonly affected. The thyroid gland regulates metabolism, energy, and mood through hormone production. Hypothyroidism (underactive thyroid) symptoms include fatigue and sluggishness, unexplained weight gain, cold intolerance, dry skin and hair, constipation, depression, and brain fog. Hyperthyroidism (overactive thyroid) symptoms include unexplained weight loss, rapid heartbeat or palpitations, heat intolerance, nervousness and irritability, tremors, and increased sweating. Diagnosis is straightforward with a blood test measuring thyroid-stimulating hormone (TSH). If TSH is abnormal, additional tests (free T4, free T3, thyroid antibodies) help determine the cause and severity. Treatment for hypothyroidism is lifelong thyroid hormone replacement (levothyroxine), which is inexpensive and widely available. Treatment for hyperthyroidism may include anti-thyroid medications, radioactive iodine therapy, or surgery. Hashimoto\'s thyroiditis (an autoimmune cause of hypothyroidism) is the most common thyroid disorder in Canada. Graves\' disease is the most common cause of hyperthyroidism. If you are experiencing symptoms suggestive of a thyroid disorder, your physician can order the appropriate blood tests. Initial assessment, lab requisitions, and follow-up can all be done through telehealth. *This article is for informational purposes only.*

This article is for informational purposes only and does not constitute medical advice. Content reviewed by licensed Canadian physicians. Last updated February 2026.