The hormone at the root of thyroid problems is called thyroxine, or T4. Thyroid disorders generally break down into two types: hyperthyroidism, in which the gland produces too much of it; and hypothyroidism, which means the body is getting too little thyroxine. You may also hear of hyperthyroidism as Graves disease, the most common form of overactive thyroid. Similarly, Hashimoto's disease is usually the disease behind an underactive thyroid. Both types of thyroid disorders can lead to a goiter, swelling that becomes more painful as the thyroid continues to grow.
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