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Hypothyroidism vs. Hyperthyroidism: Do You Know the Difference?

The thyroid gland (located on the lower front part of the neck) is a hormone-producing gland that helps in numerous bodily functions from regulating the body’s metabolism to controlling energy levels and body temperature. Therefore, the hormones produced by the thyroid have a major influence in all cells, body tissue, and organs of the body.

Unfortunately, thyroid health is very complex as thyroid conditions are commonly misdiagnosed and oftentimes, symptoms tend to mimic those of other diseases and conditions.

According to the American Thyroid Association, approximately 20 million Americans live with thyroid disease and almost 60 percent are unaware they have a thyroid condition.

With thyroid disease on the rise, it is important for the public to understand the difference between two of the most common thyroid conditions, hypothyroidism and hyperthyroidism.

What is hypothyroidism?

Hypothyroidism, simply defined, is an underactive thyroid gland. In other words, the thyroid is not producing enough thyroid hormone to keep up with the body’s demands.

The most common causes of hypothyroidism include:

  • Autoimmune disease: in cases of autoimmune disease, the body’s immune system confuses the cells of a particular organ or system as invaders and begins to attack the organ or system by destroying healthy cells. The most common form of thyroid-related autoimmune disease is Hashimoto’s thyroiditis.

  • Removal of part or the entire thyroid through surgery: it is common to remove part of all of the thyroid with detection of thyroid nodules or thyroid cancer. When all or part of the thyroid is removed, the body can no longer produce the hormone, hence depriving the body of this important hormone.

  • Radiation treatment: radiation treatment is often used in cases of thyroid cancer or Grave’s disease. It is not uncommon for individuals to lose part or all thyroid function after radiation treatment.

  • Congenital hypothyroidism: individuals are born without a thyroid or the thyroid did not fully develop.

  • Limited or excess consumption of iodine: iodine is essential for good thyroid health and not consuming enough through foods can affect thyroid function. Taking too much iodine is not beneficial either because it can overstimulate the thyroid.

What are the symptoms of hypothyroidism?

Although symptoms can often mimic those of other conditions or diseases, the following symptoms have been linked to an underactive thyroid:

  • fatigue

  • sensitive to cold temperatures

  • constipation

  • dry skin

  • sudden weight gain

  • puffiness in the face

  • hoarse voice

  • muscle weakness or pain

  • elevated cholesterol level

  • stiff or painful joints

  • irregular menstrual periods

  • hair loss

  • slower heart rate

  • depression or anxiety

  • impaired memory

  • enlarged thyroid gland (also referred to as a goiter)

What is hyperthyroidism?

Hyperthyroidism is the opposite of hypothyroidism: in other words, the thyroid gland becomes overactive and produces too much thyroid hormone.

The Society for Endocrinology states that 2 in every 100 women are affected by hyperthyroidism and 2 in every 1,000 are affected. Therefore, women are more likely to develop hyperthyroidism than men.

The most common causes of hyperthyroidism include:

  • Autoimmune thyroid disease or Grave’s disease: 80 percent of hyperthyroidism cases are a result of an autoimmune disease or Grave’s disease. Antibodies attacking the body confuse the thyroid into producing more than necessary hormones, which results in an overactive thyroid.

  • Thyroid nodules: when there are several lumps or nodules present, these can stimulate the thyroid gland to overproduce hormones.

  • Thyroiditis: thyroiditis is an inflammation of the thyroid in which tissue is destroyed and promotes the release of stored thyroid hormones. This also causes the gland to swell, making it tender to touch.

What are the symptoms of hyperthyroidism?

Commonly reported symptoms of hyperthyroidism include:

  • abrupt weight loss despite eating the same diet

  • rapid heartbeat (tachycardia)

  • irregular heartbeat (arrhythmia)

  • heart palpitations

  • increased appetite

  • nervousness or anxiety

  • tremors in hands

  • excessive sweating

  • irregular periods

  • heat intolerance

  • more frequent bowel movements

  • enlarged thyroid gland (goiter)

  • fatigue

  • difficulty sleeping/insomnia

  • skin thinning

  • fine, brittle hair

In individuals who develop Grave’s disease, a common feature is bulging eyes due to swelling behind the eyes.

What are the best tests to request if you suspect a thyroid condition?

Although most healthcare providers heavily rely on the TSH (Thyroid Stimulating Hormone), appropriately diagnosing a thyroid condition requires more extensive testing as the key is to determine the cause of the overstimulation or lessened activity of the thyroid.

Solely relying on TSH numbers alone is not recommended because it does not provide vital information about your thyroid such as how much thyroid hormone is being released, how much is stored, if your body is properly converting thyroid hormone for use, and even if your thyroid is currently under attack.

In functional medicine (which focuses on creating balance in all of the body’s systems), thorough testing is crucial for helping the patient reach optimal health. This also means that functional medicine providers use a different lab range system as the goal is to help the individual feel better based on his or her situation and not based on the conventional ranges that focus on stabilizing individuals as a population.

Therefore, if you truly want to get a thorough picture of the health of your thyroid, it is recommended that you request the following tests from your provider:

TSH: A higher TSH level can indicate that the hypothalamus is causing the pituitary gland to overwork and also be a sign that thyroid function may be low. Remember that TSH is not to be used as the only test to determine good thyroid health. Just because the TSH level is “in range” does not indicate that your thyroid is producing enough hormones to keep up with your body’s demand.

Conventional reference range: .40-4.5 mlU/L

Functional medicine optimal range: 1.8-2.5 mlU/L

Free T4: Free T4 levels are used to indicate the amount of active T4 in the body.

Conventional reference range: 0.8-1.8 ng/DL

Functional medicine optimal range: 1.0-1.5 ng/DL

Total T4: T4 demonstrates stored form of thyroid hormone and includes both the free and bounded forms of thyroid hormones.

Conventional reference range: 4.5-12 mcg/DL

Functional medicine optimal range: 6.0-11.9 mcg/DL

Free T3: Free T3 is the active form of T3. A low Free T3 level can indicate that your body is not converting enough T4 into free T3 and an indicator of hypothyroidism.

Conventional reference range: 2.3-4.2 pg/mL

Functional medicine optimal range: 2.8-3.5 pg/mL

Total T3: Total T3 levels indicate the amount of active thyroid hormones in your body this can also demonstrate if the body is able to convert T4 to T3.

Conventional reference range: 76-181 ng/dL

Functional medicine optimal range: 90-168 ng/DL

T3 Uptake: The T3 uptake test is typically used to measure other hormones such as estrogen and testosterone and their relationship with thyroid hormones.

Conventional reference range: 22-37 %

Functional medicine optimal range: 27-37 %

Reverse T3: Reverse T3 is known to slow down metabolism since it is competing with the free T3. This level can increase due to excessive stress and not a level you want to be high.

Conventional reference range: 8-25 ng/DL

Functional medicine optimal range: 10-25 ng/DL

Thyroid antibodies: Testing for thyroid antibodies is very important to determine if there is an underlying autoimmune response that is affecting the thyroid’s function. High antibodies indicate an attack on the gland and therefore, destruction of healthy thyroid tissue. There are two types of thyroid antibodies, Thyroid Peroxidase Antibodies (TPO) and Thyroglobulin Antibodies. Testing for both can uncover autoimmune diseases such as Hashimoto’s or Grave’s disease.

Thyroid Peroxidase (TPO) Ab optimal range: 0-6.8 IU/mL

Thyroglobulin Ab optimal range: 0-0.9 IU/mL

Note: Do keep in mind that suggested labs are only for a thyroid panel. There are other key factors to consider in regards to thyroid health and finding the root cause of the problem such as vitamin deficiencies, gut health, adrenal health, and sex hormones to name a few. Remember, out body is a combination of systems working together and not individual parts.



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