Let me guess. Your thyroid lab results keep coming back normal but you feel anything but “normal”.

Written by Hugh Melnick, MD

Can hypothyroidism exist when the results of a person’s thyroid blood tests are reported to be in the “normal range”?

The Hypothyroidism Paradox

Most physicians would say No! However, there are many frustrated people suffering with the classic symptoms of hypothyroidism because they were told that their blood tests “were in the normal limits” and were denied treatment, asking this very same question. The correct answer to this question, of course, is an absolute YES! People can definitely have hypothyroidism when their blood test results are reported as being “normal”. This is the Hypothyroidism Paradox. There are several fundamental reasons that explain why this paradox has existed for the past 50 years, much to the detriment of the many misdiagnosed people who continue to suffer with the symptoms of hypothyroidism.

The TSH Test

Since it first became available in the early 1970’s, the TSH test has been, and still is, the gold standard and exclusive screening test used by the vast majority of physicians for diagnosing hypothyroidism. What I don’t understand is, since only 60% of clinically symptomatic people are accurately diagnosed and adequately treated on the basis of the TSH test, why is it still being used? Why have not any of the professional medical societies, seeing this problem, recommended broadening the screening net by the addition of other available thyroid blood tests ordered along the TSH level to better diagnose clinically hypothyroid individuals? With as many as 40% of symptomatic individuals being misdiagnosed, you will not be surprised when I suggest that using the TSH level on its own is not a very good thyroid screening test. Unfortunately, the word has not  yet reached medical schools, endocrine societies and a majority of primary care physicians, who still seem to be unaware of this problem. The largely unrecognized failure of the TSH test to adequately identify many hypothyroid individuals is the first major problem that has created the Hypothyroidism Paradox.

Low Intracellular Triiodothyronine (T3)

Another major problem that plays a fundamental role in the creation of the Hypothyroidism Paradox is that the actual root cause of the symptoms of hypothyroidism is largely unknown to many physicians. An inadequate amount of intracellular thyroid hormone, Triiodothyronine (T3), is the actual root cause of the many and diverse symptoms that are experienced by people with hypothyroidism. T3 is the most potent thyroid hormone, which under normal circumstances, circulates in the blood stream and gains entrance into the interior of each and every cell in the body.

T3 is absolutely vital for normal physiologic function since it is literally the fuel that gives each cell in the human body the energy to perform its unique biologic functions. 

The way T3 works inside the cells starts with presence of T3 receptors whose existence has been documented to be in both the nucleus and cytoplasm of every cell type in the human body. The receptor is like a lock into which the T3 molecule fits. When the receptor is activated by the T3 molecule, DNA in the nucleus is activated to produce proteins that direct cellular function. When there is an inadequate amount of T3 in the cells, many T3 receptors are left empty and DNA is not prompted to synthesize the proteins required for normal biologic cellular functions. Ultimately mediated by low T3, suboptimal biologic function causes people to experience the symptoms of hypothyroidism. It is crucial to remember that a person’s symptoms are the only way to estimate intracellular T3 concentration. Simply stated, when there are symptoms of hypothyroidism, you can “bet the farm” that there is low intracellular T3.

Unfortunately, the level of T3 in the blood, both in its free and total forms, is seldom measured in symptomatic individuals having a normal TSH levels. If T3 tests were included along with the measurement of TSH levels as a screening protocol for hypothyroidism, I believe that  80-90% of symptomatic people, instead of the current diagnostic rate of 60%, would be correctly diagnosed and would receive treatment that greatly improves their health and quality of life.

Ideal Thyroid Lab Ranges for Symptom-Free Individuals

The interpretation of T3 levels is not as simple as assuming that if a person’s results fall within the reference range, they are normal and do not have hypothyroidism. Having results fall within the reference range, which used to be called the normal range, does not mean that you are normal and do not have hypothyroidism. Normal, in this case, is a statistical term that is a type of average and has nothing to do with the state of one’s health! The reference ranges  given on laboratory reports for free T3 and total T3 respectively are 2.6-4.8 and 80-220. They only mean that 95% of people tested had results that fell within that range.

The T3 ranges that are most meaningful for people having the symptoms of hypothyroidism are a bit different than the standard laboratory reference range. These ranges are established by individual physicians who, having had the experience of treating thousands of individuals over many years, have established their own “normal ranges” for both symptomatic and asymptomatic individuals.

In my experience, the ideal ranges for symptom-free individuals is 3.5-7.0+ for free T3 and 135-280+ for total T3. People having T3 levels below 3.5 free T3 and below 120 total T3 often have symptoms of hypothyroidism. Please remember that a hypothyroid individual’s T3 levels are often in the standard laboratory reference ranges. This subtle fact is the cause of many cases of missed diagnoses of hypothyroidism!

You may notice that I do not pay much attention to T4 levels in hypothyroid patients. T4 is a weak hormone called a prohormone, that the body normally converts into T3, which is the active biologic form of thyroid hormone. When there is inadequate T4 to T3 conversion, low T3 blood test results are seen, which correlates with low intracellular T3 concentrations and the clinical symptoms experienced by hypothyroid individuals. Therefore, low T3 levels in the blood produce tangible, but indirect, evidence that the patient has hypothyroidism.

Is it not easier and more direct to listen to a person’s symptoms, understanding the dynamics of thyroid physiology as outlined herein, and base the diagnosis of hypothyroidism on symptoms rather than on blood test results, that normally fluctuate? It is important to keep in mind that thyroid blood levels are variable, but thyroid symptoms are constant!

Hypothyroidism Case Study

The following Is a hypothetical Clinical Case Study illustrating the relationship between low T3 levels and the symptoms of hypothyroidism. A person is experiencing common symptoms of hypothyroidism  such as fatigue, cold extremities, weight gain, edema, brain fog and depression. Lab values are TSH=1.30, free T3=2.90 and total T3= 120. The patient is obviously symptomatic and is clinically hypothyroid. The TSH level is normal at 1.30. However, the fT3 is significantly low at 2.9, and the total T3=120, which is only minimally decreased. Please note that the fT3 of 2.90 is low, but is within the reference range. Many physicians, ignoring the patient’s clinical symptoms (which unfortunately is all too often the case) would misdiagnose the patient as having normal thyroid function because  both the results of TSH and the free T3 were “in the normal range.” Treatment would then be withheld and the unfortunate patient would continue living with the troubling symptoms that originally prompted a visit to the physician.

On the other hand, this clinical case study could have had a different ending because, if the physician recognized that the free T3 level was low and had paid attention to the patient’s symptoms, a correct diagnosis of hypothyroidism would have been made and the story would have had a much happier ending for the patient. Recognizing that the patient was symptomatic because of low T3 levels in the blood, the patient’s treatment would consist of a T3 containing thyroid medication, such as Natural Desiccated Thyroid (NDT).

The Good Old Days of Thyroid Treatment

In my experience, the optimal way to treat the symptoms of hypothyroidism is to simply keep increasing the dose of thyroid medication gradually on a monthly basis until symptoms resolve. Basing the dosage of thyroid medication on TSH suppression or by trying to get the circulating blood levels of T3 and T4 to be within the reference ranges does not work very well for many patients, who remain symptomatic despite being treated.

The “old school” approach to the treatment of hypothyroidism was using a therapeutic trial, which was actually a very effective treatment modality and is the one that I have used with my patients for my entire career. It is proof positive confirmation that the diagnosis of hypothyroidism, as well as determining the ideal dose of thyroid medication to eradicate patients’ symptoms.  Although not appropriate for most medical conditions, mainly due to potential side effects of synthetic medications and the medical profession’s misguided belief in the validity of blood test results over a person’s own description of their symptoms.

In the “good old days” of medical practice prior to the 1970’s and using a natural thyroid medication, doctors would make a diagnosis of hypothyroidism by a person’s symptoms and then give the person a therapeutic trial of thyroid medication, observing them for clinical improvement or even complete resolution of their symptoms.

Natural Desiccated Thyroid

NDT when prescribed by an experienced physician is a very safe drug, having minimal side effects. The required daily dose of NDT for most people to experience symptomatic relief is between 180-360 mg per day, although 10-20% feel well on lower doses. This is important to note because the starting dose of 60 mg per day seldom causes any dramatic clinical improvement. The gradual increase in dosage eventually leads to a “sweet spot”, usually between 180 and 360 mg per day, in which patients experience clinical improvement. At that time, the dosage can be fine tuned in an attempt to make a hypothyroid individual as asymptomatic as possible.

The greatest fear of the use of any thyroid medication is causing an abnormal heart rhythm known as atrial fibrillation. Although atrial fibrillation can be caused by hyperthyroidism (Grave’s Disease), or excessive T4 medication, some cases of atrial fibrillation are actually associated with hypothyroidism and low T3 and are cured by taking thyroid medication. Because it contains T3, whenever possible, I treat my patients with NDT, rather than synthetic T4 thyroid medication. Although it was unknown at the time, by using a natural thyroid medication (NDT was the only thyroid medication available at the time) which contains T3, avoided the T4 to T3 conversion problem that effects many individuals and prevents symptomatic relief.

The Bottom Line

The “bottom line” is best illustrated by the clinical case study that I presented above. When blood test results are the only deciding factor, there is a 50% chance that the diagnosis would be correct, and could really go either way. The correct diagnosis depends entirely upon the individual physician’s ability to properly interpret laboratory results, as well as having a knowledge of thyroid physiology and statistics and, most importantly, giving weight to the patient’s symptoms in the diagnostic analysis. When factoring in a person’s clinical symptoms into the data, the probability of a correct diagnosis increases, in my experience, to 90-95%. This also includes symptomatic patients whose comprehensive thyroid blood tests are all solidly within the reference range.

So my answer to the Hypothyroid Paradox is YES. People can and do have the symptoms of hypothyroidism with normal blood tests results, because their blood test results are not really abnormal, due mainly to incorrect interpretation or cannot be adequately tested because there is no test capable of measuring intracellular T3 levels, which is the root cause of hypothyroidism.

The Hypothyroidism Paradox does not really exist! If you have symptoms of hypothyroidism, you are hypothyroid. You deserve a proper therapeutic trial of thyroid medication to see if your symptoms can be eradicated.

About Hugh Melnick, MD

Dr. Hugh Melnick is a reproductive endocrinologist who has been treating patients with hormonal and fertility problems since 1976. In 1983, Dr. Melnick founded Advanced Fertility Services, which was the first free standing In Vitro Fertilization Center in New York City and is still its medical director. Dr. Melnick’s vast clinical experience along with his own personal experience with hypothyroidism has enabled him to develop a unique approach to the diagnosis and treatment of hypothyroidism. During his many years of clinical practice, he has recognized how hypothyroidism can adversely affect every part of the human body which inevitably interferes with a productive and enjoyable quality of life. In addition to his fertility services, Dr. Melnick specializes in hypothyroidism treatment for men and women of all ages.

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