FAQ: What are “normal” TSH levels?

Question: I just got back my TSH results from some blood work that I had done with my family doctor.  He said that my TSH levels look “normal”, but I don’t really know how to interpret this stuff.  He is not a specialist, so I don’t know if I should trust him or not.  What is typically considered “normal” TSH levels?

Answer: I’ll be honest with you here… This has been the subject of much debate lately.

The general guideline that most labs use for “normal” is between 0.5 and 5 mIU/L.  Although there are sometimes exceptions to the rule (depending on your T3 and T4 levels), this is more or less a “rule of thumb” for most doctors.

However, if your TSH levels are on either the low end or high end, you could be starting to see some early signs of high or low thyroid hormones.  If this is the case, I would ask to be referred to a specialist for a second look at those numbers.  Your family physician may mean well, but they are not experts on the endocrine system.

If you are afraid to ask for this referral, just look in the phone book under Endocrinologists, pick one and make an appointment (unless you know of one already, of course).  The Endocrinologist will probably want to order his or her own series of tests and blood work, so be mentally prepared for that.

4 Responses to FAQ: What are “normal” TSH levels?

  1. richa

    Dr,Dan, i m suffering from higher TSH,my last result shows that my TSH level was 11.0 with T3 and T4 normal……..i am taking thyrox 50 daily……but have irregular periods.i want to conceive but with these problems i can’t.please suggest me some help.

  2. azeez

    dear sir currently my tsh level has .8 is it normel?

  3. Bridgett

    The American Association of Clinical Endocrinologists changed the normal TSH range to 0.3-3.0 back in 2002…Most docs and labs are stilling using the 0.5-5.0 range which is misdiagnosing their patients…


  4. gina

    I have recently had a tsh of 4.590 and put on Synthroid for 1 month. Then my physician wants to repeat labs. Dont know wether or not to begin meds even though labs are not really high.