Hypothyroidism, or underactive thyroid, occurs when your thyroid gland doesn’t produce enough thyroid hormones (T3 and T4) to meet your body’s needs. This slows down many bodily functions.
Common Causes:
Hashimoto’s thyroiditis (an autoimmune condition) is the most common cause in developed countries. Other causes include thyroid surgery, radiation treatment, certain medications, iodine deficiency (globally), and pituitary disorders affecting TSH production.
Symptoms:
Because thyroid hormones affect metabolism, low levels cause fatigue and sluggishness, weight gain despite no change in diet, cold intolerance, constipation, dry skin and hair, hair loss, muscle weakness, depression, brain fog and poor memory, heavy or irregular periods, and elevated cholesterol. Symptoms develop gradually and may be mistaken for normal aging or stress.
Diagnosis and Treatment:
Blood tests measuring TSH (elevated in hypothyroidism) and free T4 (low in hypothyroidism) confirm diagnosis. Treatment typically involves daily thyroid hormone replacement medication. Once the correct dose is established, most people feel significantly better, though it may take several weeks to months to find the optimal dose.
