Your thyroid gland is a small gland located in the front of your neck that is essential for controlling all of the body processes associated with metabolism. Metabolic body processes include blood circulation, breathing, elimination, digestion, brain and nerve function, body temperature control and muscle contraction. The medications used to treat certain thyroid disorders can lead to weight loss.
Your thyroid gland produces two main hormones: thyroxine and triiodothyronine. These hormones control and maintain all the metabolic processes in your body. The release of hormones from your thyroid gland is controlled by a hormone called TSH, or thyroid stimulating hormone. Your pituitary gland, which is located at the base of your brain, is responsible for releasing TSH. Some people experience a condition called hypothyroidism, which is characterized by an underproduction of thyroid hormones. When your thyroid does not produce enough thyroid hormones, your metabolic processes slow down. A slow thyroid gland is often associated with abnormal weight gain.
The goal of treatment for hypothyroidism is to replace the thyroid hormones that your body is missing. Treatment, which is usually lifelong, consists of a synthetic thyroid hormone medication called levothyroxine. Levothyroxine comes in a tablet form that is to be taken once per day on an empty stomach, usually before breakfast. The goal of this medication is to replace the missing thyroid hormones and help maintain metabolic processes. Occasionally, levothyroxine will not only help maintain metabolic processes, it will speed them up. When the rate of your metabolic processes increases, you lose weight.
It is important to note that while thyroid medication can help replenish the amount of thyroid hormone in your body, it does not correct the underlying condition that may be causing an underactive thyroid.
The National Center for Biotechnology Information notes that even though levothyroxine results in weight loss in many people with thyroid disease, it should not be taken as a weight loss aid for obese adults with normal thyroid function. This use of levothyroxine has been shown to be ineffective and can cause life-threatening toxic effects.
Other medications, supplements and certain foods can interfere with the proper absorption of Levothyroxine. You should talk with your doctor about whether levothyroxine is right for you, especially if you take iron supplements or calcium supplements or eat a high-fiber diet and a large amount of soy products.