Functional Blood Markers for an Optimal Thyroid

Bree McDonough
Mar 18, 2024
5 min read

Updated: Nov 8, 2024

Have you been feeling tired, gaining weight, or experiencing brain fog?

These symptoms, among others, may be signs of an underperforming thyroid gland. The thyroid, a small butterfly-shaped gland in your neck, is responsible for producing hormones that regulate essential functions throughout your body, including your metabolism, heart rate, and body temperature. When your thyroid is not working optimally, it can lead to a cascade of health issues that can impact your quality of life.

In recent years, the functional space has emerged as a powerful approach to assessing and supporting thyroid imbalances. Functional practitioners look beyond the standard thyroid panel and consider a broader range of blood markers to gain a more comprehensive understanding of your thyroid function. By identifying and addressing imbalances in these key markers, you can take steps to optimize your thyroid health and alleviate symptoms.

In this blog post, we'll dive into the world of functional blood markers for thyroid health. We'll explore the role of each marker and how a functional approach can help you restore balance and achieve optimal thyroid function. Whether you've been diagnosed with a thyroid disorder or simply want to maintain a healthy thyroid, understanding these markers is an essential step in taking control of your health.

Thyroid-Stimulating Hormone (TSH):

TSH is a hormone produced by the pituitary gland that acts as a master regulator of thyroid function. Think of TSH as a thermostat for your thyroid. When your body needs more thyroid hormones, your pituitary gland releases more TSH, essentially turning up the heat and signaling your thyroid to produce more hormones. Conversely, when there are sufficient levels of thyroid hormones circulating in your body, the pituitary gland reduces TSH production, turning down the thermostat and slowing down thyroid hormone production.

This intricate feedback loop is crucial for maintaining optimal thyroid function. The pituitary gland constantly assesses the levels of triiodothyronine (T3) and thyroxine (T4) in your bloodstream. When T3 and T4 levels are low, the pituitary gland releases more TSH to stimulate the thyroid to produce more hormones. As T3 and T4 levels rise, the pituitary gland reduces TSH production to prevent overproduction of thyroid hormones.

Within the conventional space, a normal TSH range is typically between 0.4 and 4.0 mIU/L. However, functional practitioners prefer the optimal range for TSH between 1.0 and 2.0 mIU/L. High TSH levels may indicate an underactive thyroid, while low levels may suggest an overactive thyroid. It's important to note that TSH levels alone do not provide a complete picture of thyroid function, which is why functional practitioners consider a broader range of blood markers. It is also possible for TSH to be optimal, yet all other markers are not, which tells us the pituitary has not gotten the message yet that hormones are off balanced.

Triiodothyronine (fT3) and Thyroxine (fT4):

T3 and T4 are the two main hormones produced by the thyroid gland. They play a crucial role in regulating your metabolism which is why people want to blame the thyroid for their weight gain, energy levels and yes fatigue is a real side effect of the thyroid, and overall health. Understanding the differences between these hormones and their functions is essential for optimizing your thyroid health.

Thyroxine (fT4) is the primary hormone produced by the thyroid gland. It is known as a "prohormone" because it is not biologically active on its own. Instead, T4 must be converted into T3, the active form of thyroid hormone, in order to exert its effects on the body. This conversion process takes place in various tissues, including the liver, kidneys, and muscles, through the action of enzymes called deiodinases.

Triiodothyronine (T3) is the biologically active form of thyroid hormone. It binds to thyroid hormone receptors in the body's cells, regulating and maintaining a healthy metabolism, body temperature, and supporting brain function, among other essential functions. Essentially you want your body to have the ability to convert T4 into T3 to feel your best.

Normal ranges for T3 and T4 may vary depending on the laboratory, but they are generally between 80-230 ng/dL for T3 and 4.50-12.50 ug/dL for T4. However, it's important to note that these ranges are based on population averages and may not reflect optimal levels for individuals. Functional practitioners often consider a narrower range for optimal thyroid function and take into account factors such as symptoms, lifestyle, and overall health.

There is a small portion of thyroid hormones that is unbound and free to be more available for cellular activity. You can actually have all the symptoms of an imbalanced thyroid, yet your labs look pretty normal because thyroid hormones are having a hard time getting into the cells. These hormones would be your Free T3 and Free T4 which can give you a better picture of your thyroid hormones available to your cells.

Functional practitioners look at the optimal ranges for thyroid hormones through a much smaller lens.

Total T4 7.50 - 8.10 ug/dL

Free T4 1.00 - 1.50 ng/dL

Total T3 90.00 - 168.00 ng/dL

Free T3 3.00 - 3.25 pg/mL

Reverse T3:

If any of the thyroid hormones were to get a bad rap it would be Reverse T3, however it is not bad at all. Think of Reverse T3 as pressing on the breaks in your car to slow down as a portion of T4 is converted into Reverse T3 on a regular basis. It is when this marker goes out of range and above it’s optimal ranges, we can assume there is some type of stress impacting the body. A functional range for Reverse T3 would be between 14.90 - 26.70 ng/dL.

Thyroid Antibodies:

Thyroid antibodies, such as thyroid peroxidase (TPO) and thyroglobulin (TG) antibodies, may indicate an autoimmune presence like Hashimoto's. Elevated thyroid antibodies may lead to inflammation and damage to the thyroid gland. A functional approach to managing thyroid antibodies may include identifying and eliminating triggers, such as gluten, supporting gut health, and reducing inflammation through diet and lifestyle changes. There are no functional ranges for these markers as labs will indicate whether they are high or not. If these markers come back out of range, it is important to share these results with your doctor.

Bringing The Thyroid Back To Balance:

Your thyroid is a sensitive organ in the body and when it goes off balance, it’s only responding to another imbalance in the body. So though I know you want to focus solely on the thyroid, you really want to focus on what cause it to not function optimally.

Things that can shift your thyroid hormones are stress as cortisol can shut down the ability to transport thyroid hormones in the body. Nutritional deficiencies and iron anemia can impact the thyroid’s ability to make hormones. Estrogen dominance or even hormone replacement therapy can block thyroid receptor sites in the body impacting your thyroid levels. But insulin resistance, gut infections, and toxins like mold will all play a role in your thyroid’s ability to maintain function. This is why, if you want your thyroid to be the star of the show, you can’t focus on the thyroid but rather what is impacting the thyroid. Remember, it is only responding to something else in the body, so the key is to figure out what that something else is!

Your thyroid health is a journey, and every person’s path is different. What works for one individual may not work for another, which is why a personalized, functional approach is so valuable. By working closely with a functional practitioner, you can develop a tailored plan that addresses your specific needs, taking into account your symptoms, lifestyle, and overall health.