10 Things to Know About Thyroid Hormones

By Himanshu Sharma, Onlymyhealth editorial team

---

Thyroid hormones are produced by the thyroid gland. The thyroid gland stores these hormones, which are released when needed.

The thyroid gland is a butterfly-shaped gland that lies just below your voice box (larynx) and in front of your windpipe (trachea). The gland produces several hormones, but there are only two that are clinically relevant. These are thyroxine (T4) and triiodothyronine (T3).

Below are the 10 things that you must know about the hormones produced by the butterfly-shaped thyroid gland.

1. The thyroid gland uses iodine from food to make two thyroid hormones - thyroxine (T4) and triiodothyronine (T3). However, too much production of these hormones may speed things up or too little thyroid hormone may slow things down.
2. Both the hormones are heavily involved in energy management and and a variety of biochemical and metabolic reactions and functions throughout the body. Thyroxine is abundant in the bloodstream and is responsible for most metabolic activity.
3. The pituitary gland works together with the thyroid gland to release thyroid-stimulating hormone (TSH), which stimulates the thyroid gland to release more T3 and t4. TSH, also referred to as thyrotropin, is confused as thyroid hormone. It's a pituitary hormone that stimulates the production of thyroid hormones.
4. Our body needs thyroid hormones for normal development of the brain, specifically during the first three years of life. If a baby's thyroid gland does not produce enough thyroid hormone, intellecutal disability may occur. Children above three years also need thyroid hormones for their normal development while adults the hormones to regulate the way the body uses energy (metabolism). Thyroid hormones have a direct impact on how fast food moves through your digestive tract.
5. Thyroid hormone levels control the rate at which your body burns calories (your metabolism). Therefore, it may influence one's body weight.
6. If thyroid hormone levels are inappropriate, the heartbeat may slow down or speed up.
7. Thyroid hormones may affect body temperature and muscle strength.
8. The hormones released by the thyroid gland control how quickly your body replaces dying cells.
9. There are two main types of thyroid conditions - hyperthyroidism and hypothyroidism. Hyperthyroidism refers to the condition when the thyroid gland secretes an excess of thyroid hormones. One experiences symptoms such as sudden weight loss, increased heart rate, heat intolerance, moodiness and diarrhoea. Hypothyroidism occurs when the thyroid gland fails to secrete the required amount of T3 and T4. Common symptoms of hypothyroidism include weight gain, fatigue, dry skin and hair, goitre, sensitivity to cold and depression.
10. To diagnose thyroid imbalance, TSH test is conducted. This is to measure T3 and T4 levels in the bloodstream. In case imbalanced thyroid levels are confirmed, TSH test will be followed by a radioactive iodine uptake scan which identifies the cause of the thyroid condition, i.e., whether it has developed due to Grave's disease, goitre or thyroiditis. A series of other tests such as CT scan and MRI may be advised to determine the size and shape of your thyroid gland.