Thyroid-stimulating Hormone (TSH)

The purpose of thyroid testing is to measure the so-called “markers” of thyroid health. These are substances not only produced by the thyroid gland but other organs that regulate thyroid function.

Thyroid stimulating hormone (TSH) is the pituitary hormone that acts as a messenger to the thyroid gland. If the pituitary gland detects that there is too little thyroid hormone in the blood, it will produce more TSH, prompting the thyroid gland to produce more thyroid hormone. When the pituitary detects too much thyroid hormone, it slows the production of TSH, signaling the thyroid gland to do the same.

TSH Results Interpretations

The normal TSH range is 0.4 to 5 milli-international units per liter (mIU/L).

High Levels of TSH

If your level is higher, chances are you have an underactive thyroid. Pregnancy can also make your TSH levels higher. If you’re on medications like steroids, dopamine, or opioid painkillers (like morphine), you could also get a lower-than-normal reading.

Low Levels of TSH

It’s also possible that the test reading comes back showing lower than normal levels of TSH and an overactive thyroid. This could be caused by:

  • Graves’ disease (your body’s immune system attacks the thyroid)
  • Too much iodine in your body
  • Too much thyroid hormone medication
  • Too much of a natural supplement that contains the thyroid hormone

The TSH test usually isn’t the only one used to diagnose thyroid disorders. Other tests, like the free T3, the free T4, the reverse T3, and the anti-TPO antibody, are often used too when determining whether you need thyroid treatment or not.

Keywords: thyroid stimulating hormone; TSH; thyroid gland.

* The Content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.