The thyroid is a butterfly-shaped gland that lies in front of your windpipe, just below the voice box. The thyroid gland uses the mineral iodine from the food we eat to make thyroid hormones. The thyroid gland stores these hormones and releases them as they are needed. Thyroid hormones play a key role in normal development of the brain, especially during the first 3 years of life. Older children also need thyroid hormones to grow and develop. Adults need these hormones to regulate metabolism.
A thyroid-stimulating hormone (TSH) blood test is used to detect problems affecting the thyroid gland. A high TSH test result can indicate an underactive thyroid gland (hypothyroidism). Hypothyroidism can cause symptoms such as weight gain, tiredness, dry skin, constipation, and a feeling of being too cold. A low TSH test result can be a sign of an overactive thyroid (hyperthyroidism). Symptoms of hyperthyroidism include weight loss, rapid heart rate, nervousness, diarrhea, a feeling of being too hot. There are many reasons that the thyroid hormone may not function properly. Some are serious. Your doctor can best determine if a TSH test is needed.