What Does Thyroxine Do?

The thyroid gland is an important part of the endocrine system, secreting a number of hormones that affect everything from heart health to metabolism. One of those hormones is thyroxine, also known as T4. Because of the many functions that thyroxine impacts, it is considered one of the most important thyroid hormones. Understanding thyroxine is crucial to protecting your overall health.

How Does Thyroxine Work?

Thyroxine is a hormone the thyroid gland secretes into the bloodstream. Once in the bloodstream, thyroxine travels to the organs, like the liver and kidneys, where it is converted to its active form of triiodothyronine. Thyroxine plays a crucial role in heart and digestive function, metabolism, brain development, bone health and muscle control. It affects almost all of the body's systems, which means proper thyroxine levels are vital for health. This is why many doctors will test T4 levels along with the more common T3 levels when testing for thyroid disorders.

What Can Go Wrong with Thyroxine?

Having too little thyroxine or too much thyroxine can cause health problems. If your body releases too much thyroxine, you will suffer a condition called thyrotoxicosis. This can cause a goiter, which is a swelling of the neck because of an enlarged thyroid gland. Thyrotoxicosis can also cause menstrual irregularities, an increase in bowel movements, weight loss, heat intolerance, fatigue and irritability. Thyrotoxicosis is commonly caused by hyperthyroidism, tumors in the thyroid gland or thyroid inflammation.

The body can also produce too little thyroxine, a condition known as hypothyroidism. Low thyroxine levels cause problems with development if it occurs when an individual is young. In adults, thyroxine deficiency will lower the metabolic rate, causing weight gain, memory problems, infertility, fatigue and muscle stiffness.

What Should I Ask my Doctor About Thyroxine?

If you are struggling with symptoms of a thyroid disorder and suspect thyroxine deficiency, it's crucial that you talk with an endocrinologist. You will need a series of blood tests to determine whether or not your thyroid hormone levels are where they should be. As you discuss your thyroid health with your doctor, consider asking these questions:

  • Is thyroid function causing my symptoms?
  • What could have caused my thyroid to stop functioning properly?
  • How can I regain proper levels of thyroxine and other thyroid hormones?
  • What type of monitoring will I need while on thyroid medication?
  • How long will I need thyroid medication?

If you feel tired and are struggling with your weight, your thyroid may be to blame. Find an endocrinologist near you, and take the next step toward regaining your health.