What is the cause for nodular goiter?

A goiter is an enlarged thyroid gland. You have a gland in your brain called a pituitary that creates a hormone called thyroid-stimulating hormone (TSH). This connects to the thyroid gland. There are two purposes of TSH. First, it tells the thyroid to produce T4 and T3. Second, it causes the thyroid gland to increase in size. If there’s too much TSH, this could be why your thyroid is enlarged.

90% of the time, a goiter is a result of an iodine deficiency. Also, keep in mind that goiters can be associated with both hypothyroidism and hyperthyroidism.

When someone who has a goiter is tested, they may find that they have higher T3 levels. This is because the body is trying to compensate. They may also have lower T4 levels.