Explore the importance of thyroid health and hormone optimization for better overall wellness and energy levels.

Abstract

In our clinical practice, we frequently encounter patients experiencing persistent, unexplained symptoms despite being told their thyroid function is “normal.” This post explores the complexities of thyroid health beyond the standard Thyroid-Stimulating Hormone (TSH) test. We will delve into the critical roles of T4 and T3 hormones, particularly the active hormone Free T3, and discuss a common yet underdiagnosed condition known as low T3 syndrome or suboptimal thyroid function. I will share insights from leading researchers and explain how factors such as stress, diet, and aging can impair the conversion of T4 to T3, leading to symptoms like fatigue, weight gain, anxiety, and hair loss, even with a normal TSH. We will also examine how to interpret lab results for optimal health, not just to avoid disease, and discuss how our integrative approach, combining chiropractic care, functional medicine, and medical oversight, provides a comprehensive solution for thyroid-related health challenges.

Our Integrated Approach to Patient-Centered Care

At our clinic, Injury Medical Clinic PA, we believe in a holistic and collaborative model of healthcare. As a Doctor of Chiropractic with extensive training as a Family Nurse Practitioner and certifications in Functional and Integrative Medicine, I, Dr. Alex Jimenez, work alongside a dedicated team to address the root causes of our patients’ health concerns. A cornerstone of our practice is our multidisciplinary approach, in which I collaborate closely with Dr. Maria Guadalupe Cardenas, MD. Dr. Cardenas is Board Certified in Internal Medicine and serves as our Medical Director and Collaborative Physician. With over 40 years of experience, her medical oversight is invaluable, allowing us to merge the best of conventional and complementary therapies. This partnership ensures our patients receive comprehensive care integrating chiropractic adjustments, functional medicine protocols, personalized rehabilitation, personal injury care, and sound medical guidance, creating a truly patient-centered healing environment.

The Thyroid Puzzle: Why “Normal” Labs Don’t Always Mean You’re Healthy

For a significant portion of my career, I found myself trying to solve a puzzle for my patients. After optimizing their primary hormones, like testosterone and progesterone, I noticed that about half of them, especially women over 45, still had lingering symptoms that I couldn’t fully explain. They would report vague but persistent issues such as mild depression, lingering anxiety, and low energy.

My initial training, like that of most clinicians—whether they are medical doctors, physician assistants, or nurse practitioners—focused on a very specific protocol for thyroid assessment. We were taught to use the Thyroid-Stimulating Hormone (TSH) test as the primary screening tool. The rule was simple: if the TSH was high (typically over 4.5 or 5.0), the patient was diagnosed with hypothyroidism (an underactive thyroid) and prescribed a synthetic T4 medication like levothyroxine or Synthroid. The expectation was that this medication would lower TSH and resolve the patient’s symptoms.

However, clinical reality has shown me that this is only a small piece of a much larger clinical picture. I began to realize this about two decades ago when attending a functional medicine conference. A presenter discussed the concept of suboptimal thyroid function and the prevalence of thyroid symptoms even when lab tests appeared normal. This was a turning point. It became clear that up to 80% of my patients with these lingering symptoms might be suffering from a thyroid issue that standard testing was missing entirely. This realization has driven me to advocate for a more comprehensive understanding of thyroid health, which I’m passionate about sharing with you today.

Beyond TSH: Understanding the Critical Role of T3 and T4

There is so much misinformation surrounding thyroid testing that it’s crucial to set the record straight. The TSH test, while useful, is merely a screening tool for primary thyroid disease. It reflects a communication loop between your brain and your thyroid gland.

• How the TSH Feedback Loop Works: The brain’s pituitary gland releases TSH, which stimulates the thyroid gland to produce thyroid hormone, primarily thyroxine (T4).

• • If your circulating T4 levels are low, the brain releases more TSH to signal the thyroid to work harder. This results in a high TSH level, indicating hypothyroidism.
  • If your T4 levels are high, the brain tells the thyroid to slow down by releasing less This results in a low or suppressed TSH level, indicating hyperthyroidism.

The major flaw in relying solely on TSH is that it doesn’t tell the whole story. The thyroid gland produces about 80% T4 and only about 20% triiodothyronine (T3). While T4 is important, it’s largely a prohormone—an inactive storage form. The real workhorse is T3, the active thyroid hormone. T3 is what binds to receptors on your cells and drives your metabolism, energy production, and countless other vital functions.

Crucially, circulating T3 levels do not significantly impact TSH. This means you can have a perfectly normal T4 level and a normal TSH. Still, if your body isn’t converting T4 into T3 effectively, you can have a low T3 level and experience the full spectrum of hypothyroid symptoms. If your provider only tests TSH, or even TSH and T4, they will tell you your thyroid is normal, leaving you to continue suffering without an answer.

This is why a complete thyroid panel is non-negotiable for a proper assessment. You must insist on testing:

• TSH
• Free T4 (the unbound, available T4)
• Free T3 (the unbound, active T3)

The Silent Epidemic: Low T3 Conversion and Its Causes

By far, the most common thyroid disorder I see in my clinical practice is what we call low T3 syndrome, or poor conversion of T4 to T3. This condition is massively underdiagnosed because most practitioners are not trained to recognize it or optimize T3 levels.

The conversion of inactive T4 to active T3 is carried out by a group of enzymes called deiodinases. Several factors can inhibit these enzymes, leading to low T3 levels despite adequate T4 production.

1. Stress: Chronic stress is a primary culprit. High levels of the stress hormone cortisol directly block the deiodinase enzymes, impairing T3 conversion. This is one of the most direct ways stress contributes to disease.
2. Restrictive Calorie Dieting: The body is incredibly smart. When it perceives starvation—whether from extreme dieting, prolonged intermittent fasting, or rapid weight loss from GLP-1 medications like tirzepatide and semaglutide—it goes into survival mode. To conserve energy, it deliberately slows its metabolism by reducing the conversion of T4 to the active form, T3. We see this constantly in patients losing weight rapidly; their T3 levels plummet, and they develop symptoms like cold hands and feet, hair loss, and fatigue, even though their TSH remains normal.
3. Aging: As we get older, the efficiency of our deiodinase enzymes naturally declines.
4. Insulin Resistance: This metabolic condition, often a precursor to type 2 diabetes, can also interfere with T3 conversion.
5. Certain Medications: Interestingly, studies show that synthetic T4-only medications (levothyroxine) can, in some individuals, downregulate deiodinase activity. This explains why many patients on these medications report that while their TSH looks great on paper, they still feel hypothyroid. Their bodies are not effectively converting the synthetic T4 they are taking into the active T3 they desperately need.

Redefining “Normal”: Why Lab Reference Ranges Can Be Misleading

One of the most important concepts I teach my patients is how to interpret their lab results. When you get a lab report, you’ll see a “reference range.” It’s critical to understand that this range is not based on optimal health; it’s based on a statistical average of the population that gets tested—a population that is, by and large, not optimally healthy.

The analogy I use is this: if you were taking a test in school, would you aim to be at the low end of the bell curve? Of course not. You’d aim for the high end, where the “A” students are. The same is true for your hormone labs. You want to be on the upper end of the reference range, where healthier people reside. Research consistently shows that individuals with lab values in the upper quartile of the normal range have lower rates of cardiovascular disease, cancer, depression, and all-cause mortality.

Let’s look at Free T3. A typical lab reference range is somewhere between 2.1 and 4.5 pg/mL. A clinician will tell you that any value in this range is “normal.” However, research tells a different story.

• Studies show that Free T3 levels on the lower end of this range (e.g., 2.3 or 2.5) are associated with a higher risk of all-cause mortality, cardiovascular events, and inflammatory diseases.
• In contrast, pediatric literature indicates that 97% of healthy 18-year-olds have a Free T3 level of around 7.0 pg/mL, with the lower end of the bell curve at 4.0 to 4.5 pg/mL. A healthy 10-month-old baby can have a Free T3 level over 10!

This indicates that our adult reference ranges are dangerously skewed low. For my symptomatic patients, I aim for an optimal Free T3 level of around 4.0 pg/mL or slightly higher—the level at which people feel their best and corresponds to the lower end of what’s normal for a healthy young adult.

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THYROID DYSFUNCTION ***MUST WATCH*** (Assessment and treatment)- Video

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An Integrative and Chiropractic Approach to Restoring Thyroid Function

When we identify suboptimal thyroid function, our goal is not just to replace a hormone but to address the underlying causes of the imbalance. This is where our integrative model shines.

• Functional Medicine and Nutrition: We start by addressing the root causes of poor T3 conversion. This involves a deep dive into diet, gut health, and stress management. Removing inflammatory foods, healing the gut, and providing the body with essential nutrients for thyroid function (like selenium, zinc, and iodine) are foundational steps.
• Chiropractic Care and Stress Reduction: As a chiropractor, I see firsthand how physical stress impacts the body’s physiology. The nervous system governs every function in the body, including the endocrine (hormone) system. Misalignments in the spine, particularly in the cervical and upper thoracic regions, can interfere with nerve signals traveling to and from the thyroid and adrenal glands (which regulate stress). Through precise chiropractic adjustments, we can restore proper nerve function, reduce physical stress on the body, and help regulate the autonomic nervous system. This helps lower cortisol and improve the body’s ability to heal and convert T4 to T3. I often teach my patients techniques like box breathing and meditation to manage their psychological stress, which is just as important.
• Hormone Optimization: If lifestyle modifications and chiropractic care are not enough to bring T3 levels into an optimal range, especially as we age, we may consider hormone support. Under the medical direction of Dr. Cardenas, we can prescribe thyroid medication. Instead of T4-only medications, we often prefer a desiccated thyroid preparation (such as Armor Thyroid or NP Thyroid). These medications are derived from natural sources and contain both T4 and T3, providing the active hormone that many patients are unable to produce on their own.

Debunking the Myth: “Once on Thyroid Medication, Always on It”

I frequently hear a concern from patients: “If I start taking thyroid medication, will I have to be on it for the rest of my life?” The answer is: not necessarily. It depends entirely on the reason you’re taking it.

• If you have primary hypothyroidism (meaning your thyroid gland itself has failed), then yes, you will likely need lifelong hormone replacement.
• However, if you have low T3 syndrome due to poor conversion, the situation is different. The medication is used to restore your levels and alleviate symptoms while we work on the underlying causes (stress, diet, etc.).

Your body operates on a brilliant feedback loop. Taking supplemental thyroid hormone doesn’t permanently shut down your own production. It simply tells the brain, “We have enough for now,” so the TSH signal quiets down. If you were to reduce or stop the medication, your brain would detect the drop in hormone levels, your TSH would rise again, and your thyroid would signal to produce more thyroid hormone. It’s a dynamic system, not a permanent switch.

Take Control of Your Thyroid Health

Thyroid Awareness Month serves as a great reminder, but understanding your thyroid is a year-round necessity. It is one of the most overlooked factors in modern health, and optimizing it can be truly life-changing. If you are experiencing symptoms like fatigue, brain fog, cold intolerance, constipation, hair loss, anxiety, or difficulty losing weight, and you’ve been told your thyroid is “normal,” it’s time to dig deeper.

I encourage you to advocate for yourself. Demand a full thyroid panel that includes TSH, Free T4, and Free T3. Work with a practitioner who understands the importance of optimizing these levels, not just keeping them within a flawed “normal” range.

For a more in-depth exploration of this topic, with detailed explanations of the studies and science behind it, I invite you to read the thyroid chapter in Hormone Havoc, which is available everywhere books are sold and on Audible. My heart has desired to bring this vital information to as many people as possible to help them heal and restore their health.

 

References

• [Fliers, E., Bianco, A. C., & Langouche, L. (2015). Thyroid function in critically ill patients. The Lancet Diabetes & Endocrinology, 3(10), 816–825. https://doi.org/10.1016/S2213-8587(15)00225-9](https://doi.org/10.1016/S2213-8587\(15\)00225-9)
• Gaitonde, D. Y., Rowley, K. D., & Sweeney, L. B. (2012). Hypothyroidism: an update. American Family Physician, 86(3), 244–251.
• [Gereben, B., McAninch, E. A., Ribeiro, M. O., & Bianco, A. C. (2015). Scope and clinical significance of deiodinase polymorphism. Thyroid, 25(1), 1–14. https://doi.org/10.1089/thy.2014.0378](https://doi.org/10.1089/thy.2014.0378)
• [Holtorf, K. (2014). Peripheral thyroid hormone conversion and its impact on TSH and metabolic activity. Journal of Restorative Medicine, 3(1), 30–52. https://doi.org/10.14200/jrm.2014.3.1.03](https://doi.org/10.14200/jrm.2014.3.1.03)
• [Peeters, R. P. (2017). Subclinical hypothyroidism. The New England Journal of Medicine, 376(26), 2556–2565. https://doi.org/10.1056/NEJMcp1611144](https://doi.org/10.1056/NEJMcp1611144)
• [Wiersinga, W. M. (2014). Adult hypothyroidism. The Lancet, 383(9924), 1253. https://doi.org/10.1016/S0140-6736(14)60636-2](https://doi.org/10.1016/S0140-6736\(14\)60636-2)

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