The Thyroid Gland

This small, butterfly-shaped  gland sits at the base of our neck and is a major player in the energy production system. The thyroid produces active substances that determine how quickly the body uses energy, makes proteins and controls how sensitive it is to other hormones. It also has an important role in calcium regulation and bone health through the hormone calcitonin. Hypothyroidism is when the thyroid gland is under-active and likewise, hyperthyroidism is when the gland is overactive. Another thyroid condition known as hashimoto’s thyroiditis can often have alternations between hypo and hyperthyroidism. Hashimito’s is often considered an autoimmune disorder in which the body attacks the gland.

Every cell in the body depends upon thyroid hormones for regulation of their metabolism

How Does the Thyroid Produce Hormones?

The process of hormonal production in the body requires many pieces of the puzzle to form a complete picture. Hormonal output of the gland is regulated by thyroid-stimulating hormone (TSH), which is produced by an even smaller peanut sized gland in the brain called the pituitary. This TSH is further regulated by thyrotropin-releasing hormone (TRH) in the hypothalamus of the brain.

The primary hormones produced by the thyroid gland include:

  1. Thyroxine (T4)
  2. Triiodothyronine (T3)
  3. Calcitonin

Under the signal of TSH, the thyroid will produce thyroxine (T4) and triiodothyronine (T3). T4 is the active ingredient of the fourth most commonly prescribed drug in the United States – Levothyroxin, generic for Synthroid.  About 80% of the secretion of thyroid hormones from the thyroid gland is T4, while about 20% is T3. It is important to note that most of T4 is converted to T3 in the periphery organs such as the liver, kidney and spleen. Therefore, the health and optimal function of these organs is very important.

T3 is about 4-5 times as potent as T4, but it is present in the blood in much smaller quantities and persists for a much shorter time. It is very important that neither too little nor too much thyroid hormones are produced, otherwise the consequences may be either hypothyroidism or hyperthyroidism.

The Thyroid Feedback Loop

  • When T4 levels and to a lesser extent T3 levels are low in the blood, the pituitary gland produces more TSH to signal the thyroid to produce more. T4 down, TSH up.
  • When T4 and T3 levels up high, there is a decrease in production of TSH from the pituitary to slow the production of these hormones. T4 up, TSH down.

From a functional perspective, I prefer to see the TSH at a level of 1.2 – 2.2. It is not uncommon to see patients present with a TSH of over 4 (still within reference range), but feel lousy.


Hypothyroidism is a condition in which your thyroid gland is producing too little thyroid hormones. TSH is typically elevated and T4, T3 depressed.

  • Pale, dry skin
  • Coarse, dry hair
  • A puffy face
  • Hoarse voice
  • Elevated blood cholesterol
  • Weight gain
  • Lethargy and fatigue
  • Moodiness
  • Depression
  • Loss of libido
  • hair-loss
  • Weak nails
  • Dark under-eye circles
  • Aching muscles
  • Intolerance to cold – cold hands and feet
  • Irregular menstrual cycles in women
  • Constipation


Hyperthyroidism occurs when the thyroid gland is producing too much of the thyroid hormones. TSH is typically low and T4, T3 elevated.

  • Fast heart rate
  • Trembling hands
  • Weight loss
  • Muscle weakness
  • Warm, moist skin
  • Hair loss
  • Staring gaze
  • Nervousness and anxiety
  • Weight loss
  • Fatigue
  • Insomnia
  • Heat intolerance
  • Excessive sweating
  • Rapid heart rate
  • Heart palpitations or irregular heart rate
  • Frequent bowel movements
  • Light or absent menstrual periods

Blood Tests to Determine Thyroid Function

Getting the big picture from labwork is a solid first step towards finding out exactly what is going on with your thyroid. Unfortunately, many conventional medicine doctors may only test TSH and T4 which really doesn’t paint a complete picture of optimal thyroid function. Many times when a patient presents to my office they bring lab tests from other doctors that only evaluate these two metabolites and present with pretty much all of the symptoms of a thyroid disorder, despite being told they are “normal”. The normal reference lab ranges are grossly inaccurate, and list a TSH of 5.5 as within normal limits. A TSH level over 4 is a violent yell to the thyroid gland to work harder. As a rule of thumb, if the TSH is great than 2.5 I will investigate further.

A functional medicine approach to thyroid management takes a larger, panoramic snapshot and re-evaluates standard reference ranges within a narrower range of optimal results. This is all done in combination with how the patient is feeling, as we are so much more than a sample of numbers on a lab test.

Recommended Thyroid Tests

Initially I may start with a TSH, Free T4 and Free T3 as general health screen, however if a patient presents with the signs and symptoms of thyroid disease then a full panel is warranted. These metabolites include:

  • Thyroid Stimulating Hormone (TSH)
  • Free T4 (Thyroxine)
  • Free T3 (Triiodothyronine)
  • Reverse T3
  • T3 uptake
  • Thyroid peroxidase
  • Anti thyroglobulin antibodies

Additional Factors That Contribute to Thyroid Disorders

Thyroid dysfunction must surely not be limited to the assessment of thyroid blood markers only. This gland does not function in isolation and therefore we must make a global evaluation to identify all factors that are potential contributors. I have categorized these factors into seven categories, each of which will be discussed in future articles. 

  1. Environmental factors
  2. Gastrointestinal dysfunction
  3. Detoxification capacity
  4. Oxidative stress
  5. Immune dysfunction
  6. Nutritional factors including the all important Iodine
  7. Hormonal imbalance

Get Thyroid Help in Miami

If you would like a comprehensive assessment of your thyroid and its’ optimal functioning, please contact our Brickell office at 305.448.2600 and request a functional medicine consultation.