What Is TSH And Why Does It Affect Thyroid Medication Dosage?

A News 9 viewer has a question for Dr. Lacy Anderson about their recent thyroid labs.

They tell us their thyroid stimulating hormone is low, but their doctor lowered their thyroid medication dosage, and they'd like to know why. 

The thyroid stimulating hormone (TSH) is the hormone the pituitary gland in the brain produces to control the thyroid gland itself. If the TSH is high, your brain wants your thyroid gland to make more thyroid hormone. So, the TSH is an inverse relationship with the thyroid hormones, T3, and T4. 

In people taking thyroid medication, the TSH can let us know whether to adjust your thyroid medication dose. 

If the TSH is high, your brain wants more thyroid medication. If the TSH is low, your brain is wanting less thyroid medication, so your doctor lowered your medication dose a bit. 

Thyroid hormones are constantly in flux, so they will be going up and down normally. Sometimes the TSH is slightly out of range and we can just recheck levels in a month and the hormones may be back in range. Your doctor can help direct you on your dose and when to recheck labs.