Underactive thyroid
An underactive thyroid gland (hypothyroidism) is where your thyroid gland doesn't produce enough hormones.
Read more about the symptoms of an underactive thyroid (hypothyroidism), including tiredness, weight gain, depression and increased sensitivity to cold.
Read about the causes of an underactive thyroid (hypothyroidism), including the immune system attacking the thyroid gland and previous thyroid treatment.
Read about the importance of correctly diagnosing an underactive thyroid (hypothyroidism) using a specialised type of blood test called a thyroid function test.
Read about how an underactive thyroid (hypothyroidism) is treated. The first line treatment is a daily hormone replacement tablet called levothyroxine.
Read about the complications of an untreated underactive thyroid, including heart problems, goitre and pregnancy-related complications.