Is Your Thyroid Doctor Using the Old TSH Lab Standards?

What is TSH? TSH (thyroid stimulating hormone) is a thyroid test to diagnose thyroid disorders. High TSH is diagnosed as hypothyroidism, low thyroid problems.

Most conventional doctors rely on TSH as the gold standard to measure thyroid functioning. Many mainstream doctors do not run a full thyroid panel that should at least include Free T4, Free T3, Reverse T3, and thyroid antibodies. Unfortunately TSH alone does not provide a complete picture. If doctors are going to rely on TSH alone, however, they should at least give consideration to the controversy over the TSH normal reference range and consider this when diagnosing patients. Right? We are more than a lab number. It’s up to us to take control of our thyroid health and insist our doctors treat us the patient and not this controversial TSH lab number, even if they look at us like we are CRAZY for questioning them!

The thyroid gland is a little butterfly-shaped gland at the base of our necks. TSH stands for Thyroid Stimulating Hormone, a hormone produced in the pituitary gland in the brain that tells the thyroid how much thyroid hormone to make.

Typically, if there is a low level of thyroid hormone in the body, the pituitary will increase production of TSH to stimulate the thyroid to produce more thyroid hormone. Therefore a high TSH level suggests an underactive thyroid (hypothyroidism), while a low TSH indicates too much thyroid hormone in the body (hyperthyroidism).

In my post “Miscarriage in New York City…Be Thyroid Aware”, I outlined the TSH ranges for pregnancy and provided trimester-specific ranges. In this post I would like to discuss the normal TSH lab standards for non-pregnant adults.

Thyroid Stimulating Hormone

For many years, most mainstream doctors have considered TSH level >10 mIU/L evidence of overt thyroid failure, and levels of 5-10 mIU/L evidence of mild or subclinical hypothyroidism. Many doctors refuse to treat hypothyroidism if a person’s TSH is less than 5 mIU/L even when the patient presents with classic hypothyroidism symptoms. This strict reliance on 5 mIU/L has left many hypothyroid people suffering with debilitating symptoms and yet their doctors refuse treatment.

For over a decade there has been considerable debate about the correct upper limit of the reference interval for TSH. According to the old standards 5.0 mIU/L is the upper limit. This upper number is critical in determining who is diagnosed with hypothyroidism and who is not.

Modern medicine continues to argue within itself on the proper upper limit of the reference range for TSH.

One of the largest studies of thyroid problems in a population is the Whickham Survey, which studied the thyroid levels of 2,779 randomly selected adults living in the town of Wickham in England from 1972-1973 and subsequently followed for 20 years. Data from the twenty-year follow-up published in 1995 demonstrated an increased risk for the development of hypothyroidism once TSH exceeds 2.0 mIU/L.[1]

The third National Health and Nutrition Examination Survey (NHANES III) screened 17,353 subjects from 1988 to 1994 and excluded those with diseases or factors known to affect thyroid function. In the resultant ‘normal’ population of 13,344 subjects, 95% had TSH levels that fell between 0.3 and 2.5 mIU/L.[2,3]

These findings supported the establishment of a narrower TSH reference range and a lowering of the upper limit of the range.

The National Academy of Clinical Biochemistry (NACB) in 2002 recommended that the upper limit of the reference range be lowered:[4]

The recent follow-up study of the Whickham cohort has found that individuals with a serum TSH >2.0 mIU/L at their primary evaluation had an increased odds ratio of developing hypothyroidism over the next 20 years, especially if thyroid antibodies were elevated.

In future it is likely that the upper limit of the serum TSH reference range will be reduced to 2.5 mIU/L.

In 2003, the American Association of Clinical Endocrinologists issued a press release in support of lowering the upper limit of the reference range:[5]

Until November 2002, doctors had relied on a normal TSH level ranging from 0.5 to 5.0 to diagnose and treat patients with a thyroid disorder who tested outside the boundaries of that range. Now AACE encourages doctors to consider treatment for patients who test outside the boundaries of a narrower margin based on a target TSH level of 0.3 to 3.0. AACE believes the new range will result in proper diagnosis for millions of Americans who suffer from a mild thyroid disorder, but have gone untreated until now.

However in 2012, the Clinical Practice Guidelines for Hypothyroidism in Adults: Cosponsored by the American Association Of Clinical Endocrinologists and the American Thyroid Association recommended 4.12 as the upper limit of normal for TSH.[6] (Wait! What happened to the AACE’s press release in 2003 to reset the TSH level to 0.3 to 3.0? Do you see the craziness of all this?)

Thyroid Advocacy To Lower The Upper Limit of TSH

Thyroid advocates and many integrative physicians are fighting to narrow that range. Thyroid doctor Dr. Weston “Wiggy” Saunders posted this important message:

normal TSH thyroid

Thyroid advocate Mary Shomon, from Very Well Health Thyroid Disease, shared this important list of recommended lab tests and optimal ranges. Note the optimal TSH range listed.

optimal thyroid lab ranges

When I was initially diagnosed with hypothyroidism after the birth of my first son in 2006, I listened to my doctors unquestioningly. I assumed that my doctors were the experts and that they knew everything there was to know about this disease. My doctor was using the old 0.5 to 5.0 TSH lab standard and kept telling me my TSH was normal falling in this range, yet I felt awful. Under my doctor’s care my TSH levels rose to 10.0 mIU/L.

At a TSH of 4.0 I felt sick and tired. By the time my TSH rose to 10.0, I felt like the walking dead struggling to make it through each day.

I even had one doctor who said she only treated a person for hypothyroidism when their TSH rose above 10.0 otherwise it was unnecessary. WHAT?!! I couldn’t function at a TSH of 10. I couldn’t get up from my bed to take care of my young son.

What Should You Do?

What if you have many symptoms of hypothyroidism, but your doctor is testing TSH only and your TSH is “normal”. What should you do?

What if you are being treated for hypothyroidism but you still suffer symptoms and your doctor is insisting your treatment is fine because your TSH is “normal”. What should you do?

Don’t just accept “your thyroid is normal” from your doctor. Insist on a full thyroid panel not just TSH but also Free T4, Free T3, Reverse T3 and thyroid antibodies. Get a copy of your lab results and check your scores yourself, even if your doctor acts like you are crazy (because you are NOT)!

I’m thankful that I found a great doctor who understands that I am more than my lab numbers. My doctor listens to me and my symptoms and for this I am grateful. TSH is only a number and it doesn’t give an accurate picture of my thyroid health. There are people like me on thyroid medication who feel our best when our TSH is below the ‘normal’ range. I feel fabulous with a suppressed TSH without signs of over-medication.

If I had a doctor that looked at TSH alone, I would be a very ill woman today.

If your doctor won’t do the additional tests and insists on relying on TSH while you suffer symptoms, find a new doctor. Find a doctor who understands you are more than a lab number. There are good thyroid doctors out there. You also have the option to order your own thyroid lab tests.

Do NOT settle.


1. Vanderpump, M.P., Tunbridge, W.M., French, J.M., Appleton, D., Bates, D., Clark, F., Grimley Evans, J., Hasan, D.M., Rodgers, H., Tunbridge, F. The incidence of thyroid disorders in the community: a twenty-year follow-up of the Wickham Survey. Clin Endocrinol (Oxf) 1995 Jul;43(1): 55-68.

2. . Hollowell, J.G., Staehling, N.W., Flanders, W.D., Hannon, W.H., Gunter, E.W., Spencer, C.A., Braverman, L.E. Serum TSH, T4, and thyroid antibodies in the United States population (1988 to 1994): National Health and Nutrition Examination Survey (NHANES III). J Clin Endocrinol Metab 2002 Feb;87(2):489-99

3. Lee, S.L. When is the TSH normal? New Criteria for diagnosis and management.. Lecture presented at 12th Annual Meeting of the American Association of Clinical Endocrinologists (AACE), San Diego, CA, May 14, 2003 (

4. National Academy of Clinical Biochemistry 2002. Laboratory Medicine Practice Guidelines: Laboratory Support for the Diagnosis and Monitoring of Thyroid Disease. Retrieved from:

5. American Association of Clinical Endocrinologists (January 2003 Press Release). Over 13 Million Americans with Thyroid Diseases Remain Undiagnosed. Retrieved from:

6. . Clinical Practice Guidelines for Hypothyroidism in Adults: Cosponsored by the American Association Of Clinical Endocrinologists and the American Thyroid Association. Retrieved from: https://www/

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About Dana Trentini

Dana Trentini M.A., Ed.M., founded Hypothyroid Mom October 2012 in memory of the unborn baby she lost to hypothyroidism. This is for informational purposes only and should not be considered a substitute for consulting your physician regarding medical advice pertaining to your health. Hypothyroid Mom includes affiliate links including the Amazon Services LLC Associates Program.


  1. I have felt awful for several years. My primary doctor only goes by TSH. Mine has ranged from 3 to4. My hair is falling out, nails are brittle, dry skin, use to be hot, now always cold, in a fog, treated for depression, and incredibly fatigued. I finally went to an endo and was told my tests were normal, isn’t that great? My results may be in the old range but not in the functioning, or optimal range. Yay, my tests are called normal, but I feel sicker and sicker! Can anyone else relate??

  2. Hi, I have been trying to figure if my numbers are at an optimal range. I feel my endo is not concerned about my plethora of symptoms.
    I have been feeling like I’m trapped in my own body for a while. I suffer from constant mood changes, irritability, hair loss, weight gain and loss, irregular periods, heart palpitations, extreme anxiety and vision loss( I was diagnosed with chronic dry eyes and in almost blind in one eye. I have bad circulation and tingling and numbness in my fingers, suffer with dizziness and vertigo often and lightheaded
    This are my quest diagnostics labs
    TSI 143
    T3 free 2.8
    T4 free 1.3
    FSH 3.3
    VItamin D 45
    TSH 0.87
    LH 3.3
    PROLACTIN 14.7
    Estrone lc/ms/ms 51
    Estriol serum <0.10
    Testosterone total 20
    Testosterone free 1.6

    I hope someone can provide some assistance. I'm in the process of finding another endo.

  3. walter blake says

    Dear Mom, My tsh was 0.01 on 175mcg levo, and I felt great. My tsh is now 0.01mcg on 150mcg levo, and I have many hypo symptoms and feel***. Have you heard of other cases where the patient had hyper test results with hypo symptoms? Thank you in advance for your assistance. Walt

    • Hi Walter, Yes I hear from Hypothyroid Mom followers that have suppressed TSH (below normal) and feel great without symptoms of overmedication like rapid heartbeat, tremors, insomnia, shaking, rapid weight loss, etc. This is the case for me where I feel my best when my Free T3 is top quarter of the normal range but my TSH is low like yours but I feel great. This can be confusing for doctors that only look at TSH, especially for those of us on T3 medications like natural desiccated thyroid. Here’s an article about this on my site:

  4. good afternoon everyone, i feel everyone’s frustration. I havent felt the same since i had my thyroid removed ten years ago. if your doctors are not giving you concrete answers of help find someone else. i seen several endos and all of them were like “no it doesnt have anything to do with your thyroid condition.” which is bullshit…….. I started researching and self helping myself. The aching of my joints, low libido, dry hair, tiredness, etc. I started taking sea kelp and selenium everyday, and the aching joints and fatigue is much better. The only thing that i was told to take was the Vit D. No doctor recommended the iodine. i was running from this doctor to that doctor thinking that it was other issues going on when it wasnt. I see a new doctor on june 12 and im asking for a full blood workup. if the doctor is not willing to treat and teach you about your condition, find someone that will and try to help yourself. change your diet and exercise. read about supplements. my issue right now is heart palpatations and acid reflux which i know has come from the thyroid issue. my meds might need to be changed….. when all in doubt go get your TSH checked asap.

  5. I would recommend to everyone: Look online for Dr. Amy Myers and Dr. Izabella Wentz, they are thyroid gurus. Also try the paleo diet, it will probably help.

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