Is Your Hypothyroidism Being Undertreated?

It's possible to have a "normal" TSH level and still feel unwell

Tired woman using cell phone in kitchen
Squaredpixels/Getty Images

If you're on thyroid hormone replacement and have a thyroid-stimulating hormone (TSH) level that's in the normal range—yet you are still having a range of thyroid-related symptoms—you may be one of the millions of thyroid patients suffering from undertreated hypothyroidism.

About 15 percent of people in the U.S. with hypothyroidism, or an underactive thyroid, continue to feel unwell despite being treated for the disease, according to a 2016 study published in the Journal of Clinical Endocrinology and Metabolism.

That means that 1.5 to 1.8 million Americans currently taking thyroid hormone replacement therapy have persistent symptoms of an underactive thyroid. If you think you fit this description, it's important to have a discussion with your doctor about optimum TSH levels and thyroid drug options.

What Is Undertreated Hypothyroidism?

The term refers to hypothyroidism at the cellular level that means you still have hypothyroidism symptoms such as fatigue, weight gain, depression, fibromyalgia/muscle and joint aches and pains, hair loss or coarse/dry hair, infertility, constipation, brain fog, and more—despite taking the recommended amount of thyroid replacement and having a "normal" TSH blood level. Unfortunately, normal blood TSH levels are weighed more heavily by most doctors than the patient's symptoms when judging the adequacy of treatment.

There are two reasons this can occur. First, some doctors believe that providing only enough thyroid hormone to get a patient to mid to high-normal TSH levels is sufficient.

The second, arguably more common reason is that the current standard treatment of Synthroid, Levoxyl, Levothyroid, Eltroxin, or Euthyrox (generic levothyroxine) may not be enough for some people to actually feel well. Levothyroxine is the pharmaceutical grade of T4, which the body must convert into T3, an active hormone.

T4 is inactive. However, some people may struggle to convert T4 into adequate amounts of T3, leaving them with persistent hypothyroid symptoms.

If you don't feel well on levothyroxine monotherapy, you may want to try "combination therapy" which is a medication that contains both T3 and T4. Even though this is supported by the American Thyroid Association, many doctors don't have experience prescribing it.

TSH Levels

Some endocrinologists believe that a TSH of less than 2 is optimal for most people to feel well and avoid having hypothyroid or hyperthyroid symptoms. There is also research that suggests that values above TSH of 2 may actually even represent abnormal levels.

(NOTE: TSH levels are usually kept lower than 1 to 2 for thyroid cancer survivors—a process is known as thyroid suppression—to help prevent cancer recurrence.)

  • TSH Less than .3 - This is considered potentially hyperthyroid (too much thyroid hormone) at most labs in the U.S. You may be anxious, find it hard to sleep, hair falling out, diarrhea, and other symptoms.
  • TSH 1 to 2 -The optimal normal level for most people. This is the  TSH range where the majority of people feel best. It is sometimes considered "too low" by less-informed doctors.
  • TSH .3 to 4.5 - The "reference range" according to some lab standards. Some people feel well in this range, but many suffer low-grade hypothyroidism symptoms when the TSH is above 2.0. ​
  • TSH 4.5 to 10 - Considered "subclinical hypothyroidism" levels, but amazingly, some doctors won't even treat these levels and do not attribute hypothyroidism symptoms felt by patients at this level to the hypothyroidism itself. Many people have symptoms at these levels.
  • TSH Above 10 - Considered hypothyroid that merits treatment by most doctors.

You May Need T3 to Feel Well

Some people do not feel well on a levothyroxine/T4 only drug (like Synthroid) and feel far better-taking T3.

Others have had success adding T3, such as in the form of Cytomel or via compounded, time-released T3, to their levothyroxine. Finally, yet others have had success with Armour, the natural thyroid hormone replacement. There are many thyroid hormone replacement options

Surprisingly, It's still considered controversial to use T3 for people with hypothyroidism by the less innovative or accepting members of the medical world, despite research that clearly demonstrates the need for T3 in many thyroid patients. Many people have a normal or even low-normal TSH level, yet still, suffer continuing hypothyroidism symptoms. In these cases, the addition of T3 helped relieve depression, brain fog, fatigue and other symptoms. This information about T3 is quite revolutionary and has major implications for people who don't feel well on their current thyroid therapies! For more info, see my full report on this research.

How to Broach the Conversation With Your Doctor

If you're still suffering hypothyroidism symptoms despite treatment, your first step is to document this in a way that you can review easily with your doctor. A good tool to help is the hypothyroidism symptoms checklist, which offers a checklist of risk factors and symptoms you can take to your doctor to help get a diagnosis, or make the argument that your hypothyroid symptoms are not resolved by your current treatment. 

Before you have your discussion with the doctor, I'd also suggest you read the six critical questions you really should ask your doctor about your hypothyroidism, as well as the main questions a newly diagnosed person with hypothyroidism often asks—such as how long it takes to feel better after starting treatment, long-term health risks, whether or not you'll get a goiter, fatigue and weight gain and how to combat them, and more.

Armed with information and your checklist, you should sit down and have a discussion with your doctor about your optimal TSH level, and whether or not you should be considering the addition of T3 to your thyroid hormone replacement therapy.

You may also need some ammunition in getting your doctor to listen and understand. To help, there's are various books that I recommend for all thyroid patients. See The Thyroid Bookstore for ideas.

If your doctor won't discuss options or refuses to consider the T3 therapy, then you'll need to find a doctor who wants to be your partner in wellness.


Sarah J. Peterson, Elizabeth A. McAninch, Antonio C. Bianco.Is a Normal TSH Synonymous with “Euthyroidism” in Levothyroxine Monotherapy? The Journal of Clinical Endocrinology & Metabolism, 2016; jc.2016-2660 DOI: 10.1210/jc.2016-2660