Thyroid hormones regulate our body's metabolism and influence virtually every organ system in the body. They tell organs how fast or slow they should work. Thyroid hormones also regulate the body's consumption of oxygen and production of heat. Thyroid problems, such as an overactive or underactive thyroid, can severely affect metabolism. There are several thyroid conditions you may want to be aware of. Our program includes comprehensive testing of the thyroid gland (TSH) in addition to the thyroid hormones , thyroxine (T4) and triiodothyronine (T3). When the thyroid gland does not produce enough hormone, the body uses energy at a slower pace than it should. This condition, underactive thyroid, is called hypothyroidism.