Thyroid Disease

Thyroxine is a body chemical (hormone) made by the thyroid gland in the neck. It is carried round the body in the bloodstream. It helps to keep the body's functions (the metabolism) working at the correct pace. Many cells and tissues in the body need thyroxine to keep them going correctly.

Hyperthyroidism is also known as thyrotoxicosis or an overactive thyroid. It occurs when the thyroid gland makes too much thyroxine. This causes many of the body's functions to speed up.

Hypothyroidism is also known as an underactive thyroid. It occurs when the thyroid gland does not make enough thyroxine. This causes many of the body's functions to slow down.