The TSH Story
What's the Deal About TSH?
TSH. Try Something Harder. It can feel like you always have to do that when your thyroid isn't working right, but TSH stands for Thyroid Stimulating Hormone. The TSH test is the main one that doctors use to diagnose hypothyroidism or hyperthyroidism, so it's an important test to understand.
The TSH is a pituitary hormone, not a thyroid hormone. Its job is to stimulate the thyroid to produce more thyroid hormone, so a high TSH usually indicates that your body isn't getting enough thyroid hormone. This condition is hypothyroidism. A too-low TSH usually indicates the opposite, or hyperthyroidism.
The main problem with the TSH test is that the range for it is too wide at most labs. Some labs have ranges that go as high as 6, but according to a number of sources that we have compiled, symptoms of hypothyroidism accompanied by a TSH over 2, sometimes over 1.5, are suspect. Whenever you get lab tests, ask for a copy of the results. Don't just let someone tell you that your TSH is "normal."
Another problem with going by TSH levels is that because the TSH is a pituitary hormone, sometimes it doesn't tell the thyroid story. If there's a problem with the pituitary gland, or the hypothalamus (which controls the pituitary), the TSH could be at an optimal level, but your actual thyroid hormones (T4 and T3) could be too low, or too high. Using the TSH to check for thyroid problems in this situation is like looking at the thermostat to check the temperature of a house when the thermostat itself is broken.
A good starting point to learn more about this is Mary Shomon's article, "HELP! My TSH Is 'Normal' But I Think I'm Hypothyroid."
If you have a "normal" TSH level but you still think you are hypothyroid, ask for more thyroid testing, such as free T4 and free T3 tests, and perhaps a TRH stimulation test. Note that hypERthyroidism can also be missed by relying too much on the TSH; some people get symptoms of hyperthyroidism when their TSH is in range, but at the low end of the range. You can also print our files of references and experiences on this subject to bring to your doctor. If you think you are undertreated, you can use these compilations to ask your doctor about a dosage increase.
Keep in mind that some other health conditions have symptoms that are similar to those of a malfunctioning thyroid. For more on this, see Maybe It Isn't Your Thyroid in our Archives section.
Where Are Those References?
See the links at the right on this page. The "TSH References" compilation starts with medical journal references because they are the most important to doctors, but if this subject is new to you, you'll probably find the other articles easier to digest first. In the "TSH: Patients' Experiences" compilation, you can read how getting the TSH at the right level greatly improved the lives of many thyroid patients.
T3 levels may be another piece of the puzzle to feeling well. See also our T3 Supplementation article and links.