Written by Dr. Michael Fucci, DC, CFMP, MSACN
Published November 1, 2025

Introduction: When “Normal” Isn’t Normal

If you’ve been dealing with cold hands and feet, low energy, brain fog, or slow recovery from workouts, you may have wondered if your thyroid is to blame.

Maybe you even asked your doctor to run thyroid labs, only to be told, “Everything looks fine.”

But, what if your doctor is ordering the wrong thyroid tests?

Why Most Doctors Only Check TSH

I was inspired to write this after seeing five different clients this week who were told their thyroid was “normal” despite having classic hypothyroid symptoms.

When I reviewed their lab results, every single one had only been tested for TSH (thyroid stimulating hormone)- and nothing else.

TSH only measures how much your brain is signaling your thyroid to “turn on” and produce hormones, not how well your thyroid is actually functioning. It can also fluctuate due to fasting, stress, illness, or even time of day, making it a poor standalone marker of thyroid health.

What a Complete Thyroid Panel Includes

If you truly want to understand how your thyroid is functioning, you’ll need a more comprehensive panel.

Here’s what a complete thyroid panel should include:

TSH,
Total T4; Free T4
Total T3; Free T3
T3 Uptake
Reverse T3
Thyroid Peroxidase Antibody (TPO)
Thyroglobulin Antibody (TG)
Binding proteins (TGB and TTR if needed)

Each of these markers provides valuable insight into how your thyroid, and your body overall, are functioning.

Why This Matters to You

When your thyroid isn’t functioning properly, it affects more than just your energy. You may notice:

Struggling to lose weight despite diet and exercise
Constant fatigue that coffee can’t fix
Brain fog that makes work and daily tasks feel harder
Muscle soreness or slow recovery from workouts
Mood swings or low motivation

Ignoring these signs or relying on a single TSH test can leave you stuck, frustrated, and wondering why you aren’t feeling better.

Getting a comprehensive thyroid panel gives you the insight you need to address the root cause of your symptoms, not just mask them. With the right information, you can create a targeted plan to restore your energy, metabolism, and overall wellbeing.

Why These Markers Matter

The thyroid is part of your endocrine system, the networks of glands that secrete hormones directly into your bloodstream. It produces hormones that help regulate metabolism, energy, recovery, and even mood.

An underfunctioning thyroid is often more than just low energy. It can be a source for weight gain, poor recovery in the gym, joint stiffness, cold hands and feet, poor memory, and so many other things. To understand why this is the case, we really need to understand exactly what the thyroid does and what all of those markers are.

How Your Body Converts T4 to T3

The main “product” that the thyroid produces is thyroid hormone. The two key nutrients to make thyroid hormone include the trace mineral iodine and the amino acid tyrosine. The thyroid primarily produces T4 (the inactive hormone), and a smaller amount of T3 (the active hormone). “Total” measures both bound and unbound hormone, while “free” measures the active hormone that’s available for your cells to use.

Your body must convert T4 (the inactive hormone) into T3 (the active hormone) to actually use it. Most of this conversion happens in:

The liver (60%)
The gut (20%)
Peripheral tissues like the skin and lungs (20%)

This means healthy liver and gut function are critical for healthy thyroid activity. Even if your thyroid produces enough hormone, poor conversion can make you feel sluggish, foggy, and fatigued.

The Role of Reverse T3

Your body also created Reverse T3, which acts like a “metabolic brake.” It prevents too much active thyroid hormone from overstimulating your metabolism.

However, when Reverse T3 levels get too high, it can block the effects of T3, causing symptoms of hypothyroidism even if your thyroid hormones look normal on paper.

Common reasons for elevated Reverse T3 include:

Chronic stress
Illness or inflammation
Low-carbohydrate diets
Pregnancy

This is why it is crucial to check all the thyroid markers, not just TSH.

Autoimmune Thyroid Issues

Two additional markers– TPO and TG antibodies– can help determine whether your thyroid issue has an autoimmune component, such as Hashimoto’s thyroiditis.

Autoimmune thyroid conditions require a different approach, focusing on calming immune system overactivity and reducing inflammation, not just balancing hormones. We recommend consulting with a doctor trained in functional medicine or Applied Kinesiology, as these doctors are trained to look for the root cause of your condition and not to mask symptoms.

Applied Kinesiology & the Thyroid Connection

In Applied Kinesiology (AK), we look beyond lab results to find signs of thyroid imbalance throughout the body.

Common thyroid-related signs include:

Fatigue
Low body temperature
Slow wound healing

Less obvious signs can include:

Chronic shoulder or wrist pain (without an explicit injury causing the pain that seems to “come out of nowhere”)
Recurring rotator cuff issues
Difficulty lifting your arm overhead

I’ve seen many of these musculoskeletal issues improve significantly once thyroid function is properly supported. The body is truly interconnected.

Root Causes of Thyroid Dysfunction

A sluggish thyroid rarely happens in isolation. It’s usually the result of deeper imbalances that affect how your body produces, converts, or uses thyroid hormones.

Nutrient Deficiencies
Low levels of iodine and tyrosine (the building blocks of thyroid hormones) can impair production.
Vitamins A, C, E, magnesium, and selenium are also crucial for thyroid function. And if you’re not getting enough protein, your body may not have enough tyrosine to make thyroid hormone efficiently.
Impaired Liver Function
Since 60% of thyroid hormone activation happens in the liver, anything that stresses your liver can affect your thyroid.
Common culprits include:
- Fungal overgrowth
- Alcohol
- Heavy metals
- Chemical exposure
Gut Dysbiosis
An imbalance gut microbiome can block the conversion of T4 and T3 and reduce absorption of essential nutrients. This is one reason functional medicine always includes gut health in the thyroid conversation.
Food Sensitivities/ Allergies
Food sensitivities are one the most overlooked drivers of thyroid dysfunction.
Certain foods, known as goitrogens (such as soy, flax, cruciferous vegetables, peanuts, and sweet potatoes) can disrupt thyroid hormone production– especially if your body is already sensitive or inflamed.
Iodine Competitors
Halogens like bromine, chlorine, and fluorine compete with iodine for absorption. This competition can reduce iodine availability and slow thyroid hormone production.
Heavy Metals
Metals like mercury can bind to thyroid tissue and disrupt its function. Identifying and removing these toxins is key to restoring balance.

When It’s Time to Dig Deeper: The Functional Medicine Approach to Healing

If your labs say your thyroid is “fine,” but you still feel anything but, it may be time to look deeper.

A complete thyroid panel, and root-cause approach through functional medicine and AK, can help uncover the underlying reason your thyroid isn’t performing optimally.

In our clinic, Goodlife Health, we address the whole picture, not just one lab number. Our whole-body approach is a combination of functional medicine and applied kinesiology (running the right labs, uncovering what your thyroid is really doing, and identifying the root causes holding you back), so we can help your body find balance again and get you back to feeling clear-headed, energized, and strong.

You deserve answers and a plan that’s personalized to you.

Schedule your free Discovery Call today and take the first step toward restoring your energy, focus, and balance.

The Thyroid Labs Your Doctor Isn’t Running (But Should Be)