5 Common Myths About Thyroid Disease

Man on a tablet
JGI/Tom Grill/Getty Images

Whether it is social media or a well-meaning friend or colleague, you may not be getting accurate information regarding your thyroid.

Here are five very common thyroid myths you may have come across, along with the real story you need to know.

1. Your Levels Are "Normal"

The problem with this statement is that a "normal" TSH level depends on a couple of factors like age, as well as the reference range the doctor is using.

For example, according to the vast majority of laboratories in the United States, a "normal" TSH is between approximately 0.5 to 4.5 or 5.0 milli-international units per liter (mU/L). However, some experts believe that the upper limit of a normal TSH should be lower (closer to 2.5 mIU/L). That said, narrowing the "normal" TSH reference range would mean that many more people would be diagnosed with hypothyroidism, which is why most experts stick to the 4.5 or 5.0 mIU/L reference range.

With regards to age, as a person gets older, their TSH naturally rises. So while a doctor may target a TSH lower than 4.5 mIU/L in a younger adult with hypothyroidism, in older people (age 65 or 70 and older), a TSH of 3.0 to 6.0 mIU/L may be more appropriate.

Keep in mind, as well, that achieving a "normal" TSH level is not the only goal when a doctor is treating a person's hypothyroidism. Other goals include reducing symptoms (for example, fatigue or constipation), decreasing the size of a goiter (if present), and avoiding over-treatment (which can be harmful to the heart and bones).

In the end, try not to get too bogged down with all the details. Rather, when your doctor states that your TSH level is "normal," ask what "normal range" he is using to make that determination and what your results mean for your unique thyroid health.

2. If You Have a Thyroid Problem, Take Iodine or Kelp

Some well-intentioned, but ill-advised people may be quick to tell you that "thyroid problems mean you need iodine" or iodine-containing herbs or supplements, such as kelp, bladderwrack, and bugleweed.

Let's first sort out the iodine-thyroid issue which can be confusing. To start, your body does not make iodine on its own. Instead, iodine is found naturally in the soil and seawater, so most people obtain iodine either by consuming iodized table salt and/or by eating foods that contain iodine, like dairy products, saltwater fish, shellfish, and eggs. 

Since iodine plays a critical role in thyroid hormone production, a deficiency may cause a goiter and hypothyroidism. However, for the vast majority of people with hypothyroidism in the United States, their thyroid disease is autoimmune-related, and not due to iodine deficiency. Taking iodine, therefore, would not be helpful, and may actually be harmful, as too much iodine can worsen a person's underlying thyroid disease.

3. You Have Hyperthyroidism and Need Radioactive Iodine (RAI) Treatment

The autoimmune thyroid disease, Hashimoto's disease, mostly results in hypothyroidism and is more common than Graves' disease, which causes hyperthyroidism.

However, at some stages of Hashimoto's disease, and in particular, often during the early stages, the thyroid may actually spurt into action and become temporarily overactive, making a person hyperthyroid (called "Hashitoxicosis").

In fact, sometimes it's the temporary hyperthyroidism symptoms, such as anxiety, heart palpitations, fast pulse, weight loss, diarrhea, and insomnia, that first bring a person with Hashimoto's disease to the doctor.

This is why it's critical to undergo a thorough workup to confirm a diagnosis of Graves' disease before undergoing radioactive iodine treatment. Positive thyroid-stimulating immunoglobulin (TSI), which is a blood test, confirms the diagnosis of Graves' disease. In some people with Graves' disease, however, this blood test is negative. In these instances, a radioactive iodine uptake imaging test can confirm the diagnosis.

4. Basal Body Temperature Can Diagnose Hypothyroidism

While hypothermia, or low body temperature, is a known symptom of hypothyroidism, measuring basal body temperature (BBT) as a diagnostic tool is flawed. This is because while your thyroid gland regulates your body's metabolic rate and temperature, there are other factors at play that influence your BBT (for example, hormones and external factors, like the time of day).

The bottom line is that using your BBT to diagnosis or manage a thyroid problem is not a sensible approach, as it simply cannot be safely relied upon. Instead, we have scientifically-proven, blood tests, like thyroid stimulating hormone (TSH) and free thyroxine (T4), that can most accurately gauge your thyroid function. 

5. The Only Treatment for Hypothyroidism Is Synthroid

Perhaps one of the most common fallacies doctors regularly repeat is that Synthroid is the only treatment for hypothyroidism. To clarify, Synthroid is a brand name for the drug "levothyroxine"—a synthetic form of the thyroid hormone thyroxine, also known as T4. Other brands, considered equally effective by most practitioners, include Levoxyl, Levothroid, and Unithroid. Some patients find that they respond best to one brand (not necessarily Synthroid), due to the way that brand dissolves and is absorbed, or due to the fillers and dyes used by the different manufacturers.

In addition to the levothyroxine drugs, there is also Cytomel, or liothyronine, which the generic name for triiodothyronine (T3). Adding T3 to levothyroxine may help some people relieve symptoms more effectively than levothyroxine alone—although, this is not a traditional practice.

Finally, there is the category of prescription drugs known as natural desiccated thyroid, which are FDA-approved and manufactured from the dried thyroid gland of pigs. These drugs, including Armour Thyroid, Nature-throid, and WP Thyroid in the United States, should not be mistaken with over-the-counter glandular thyroid supplements, which are not regulated by the FDA for their safety or effectiveness.

Natural desiccated thyroid drugs contain both thyroxine (T4) and triiodothyronine (T3). Some practitioners, and in particular holistic and integrative health experts, find that natural thyroid is optimal for some patients.

Was this page helpful?
View Article Sources