FAQ: Can I have an underactive thyroid with normal TSH levels?


Question: I have been going back and forth with my family physician for about 6 months now.  My TSH levels are in the normal range, but they are on the higher side of the chart (at about 3.9 mIU/L or so).  I have also experienced a lot of weight gain without any change in my daily routine or diet.  My energy level is low and I just feel “run down” and achy all the time.  Can I have an underactive thyroid with “normal” TSH levels?

Answer: Anything is possible.  Your thyroid doesn’t produce TSH… your pituitary gland produces TSH.  It does this when it detects that your thyroid gland isn’t producing enough T3 and T4 thyroid hormones.

So, being two completely different organs, it is quite possible that one of three conditions are occurring:

  1. Your pituitary gland is not accurately detecting the thyroid hormones in your bloodstream… OR
  2. Your pituitary gland is producing TSH regardless of what it detects in the bloodstream at any given point… OR
  3. Your thyroid is ignoring the signals (TSH) from the pituitary gland and continuing to under-produce T3 and T4 hormones.

You see?  Different organs that are supposed to talk to each other and work together… but, that is a system of communication that can break down and fail.

I know that your family physician means well, but there is a limit to what he or she is willing to diagnose and prescribe.  Ask for a referral to an Endocrynologist in your local area and get a second opinion.

3 Responses to FAQ: Can I have an underactive thyroid with normal TSH levels?

  1. Jill Higgerson

    This is exactly the information I needed. My TSH levels are normal, but my T3 levels are off. Have not gone to an endo specialist yet but that will be my next step.

  2. kris

    what would be the cause for normal tsh and t4 but high t3? i am currently on a statin for high cholesterol that i got from eating bad(out every day)i am choosing to become vegan due to this..but my t3 didnt get high til i got on a regular medication (lipitor) my doc seems to just want to monitor it. i have 2 small nodules also…but she states only really the tsh matter..

  3. mandy

    why would a dr treat hypothyroid (8.5) with 2.5 mg of MMI?