Hi I'm Dr. Allen Peters, Physician & Healthy Aging Expert from www.NourishingWellness.com and I'm here today for About.com to talk to you about TSH. What is TSH? TSH stands for thyroid stimulating hormone. It is produced by the pituitary gland and its job is to direct the thyroid gland to produce the right amount of thyroid hormones. It actually stimulates the production of thyroxin, which is commonly known as T4, which is then converted in the liver and the thyroid gland to triiodothyronine, which is commonly known as T3, which is actually the more active thyroid hormone. These hormones are major controllers of the metabolic functions of the body and so the TSH is an essential measurement that we all should be doing to check for thyroid problems. The reason that that is important is because a high TSH may mean that your thyroid gland is not functioning very well, and that’s indicating to the pituitary gland that it needs to put out more thyroid stimulating hormone. This may very well be an indication of hypothyroidism. And conversely, if your TSH is very low, it means that the thyroid gland is putting out too much thyroid hormones and that is very likely an indication of hyperthyroidism. So it’s a good guideline for a physician to check to see how your thyroid is functioning. Thank you for watching. To learn more, visit us online at About.com.