Dr. Jackson McKeehan, DC
If you’ve ever felt like your energy just isn’t what it used to be, dragging through the day, cold when others aren’t, or frustrated that your labs come back “normal”, but you still don’t feel like yourself, your thyroid might be quietly asking for attention.
Thyroid disorders are one of the most common hormonal imbalances in the world, and they’re on the rise. In fact, here in the U.S., hypothyroidism, when your thyroid doesn’t produce enough hormone—has climbed from affecting 9.6% of the population in 2012 to nearly 12% by 2019. Women are hit the hardest: they’re about five to nine times more likely than men to experience thyroid problems, and for most, it’s caused by Hashimoto’s thyroiditis, an autoimmune condition that slowly wears down thyroid function over time.
The most common treatment is levothyroxine, a synthetic form of the thyroid hormone T4. It’s prescribed so often that in 2023 it was the #1 most filled prescription in the U.S., even beating out vitamin D and antibiotics. Yet, many people taking it still report fatigue, weight gain, brain fog, and mood swings. Why? Because for some, the issue isn’t just the amount of hormone, but how well that hormone is actually working in the body.
Table of Contents
Your Thyroid Hormones: The Symphony Behind the Scenes
Your thyroid gland doesn’t work alone, it’s part of a team. The brain’s pituitary gland sends out a hormone called TSH (Thyroid Stimulating Hormone) to tell the thyroid how hard to work. The thyroid responds by making T4 (thyroxine), which is the storage form of thyroid hormone. Think of T4 as a warehouse full of potential, it doesn’t do much on its own until it’s converted into T3 (triiodothyronine), the active form that actually fuels your metabolism, mood, and energy.
Here’s an analogy that really helps:
Imagine your bloodstream as a highway full of cars. The cars are the total thyroid hormone, and inside those cars are the free hormones, the ones that can actually get out and go to work in your cells. Most of the cars are “bound” to carrier proteins, they’re just driving around, waiting for the right time to drop someone off. But only the passengers (the free hormones) can actually step out, enter the tissues, and make things happen.
So, if your doctor only looks at “total” hormone levels, it’s like counting the cars but not the passengers, you might have plenty of hormone in circulation, but not enough that’s actually active in your body.
T4 makes up the majority of your thyroid hormone, but T3 is three to five times more powerful. Interestingly, your thyroid only makes a small amount of T3 directly. Most of it comes from conversion, your liver, kidneys, brain, and muscles turn T4 into T3 through a process that depends on key nutrients like selenium and zinc.
Reverse T3: When “Normal” Labs Still Don’t Feel Normal
Now here’s where things get really interesting, Reverse T3 (rT3). It’s the mirror image of T3, but it’s inactive. Your body makes more of it when you’re sick, stressed, or recovering from an illness. Think of it as your body hitting the “energy saver mode” button, slowing down metabolism to conserve resources.
That’s helpful in short bursts (like during an infection or intense stress), but if Reverse T3 stays high for too long, it can start blocking the effects of real T3. The result? You might have “normal” labs on paper but still feel sluggish, foggy, and cold. It’s like having the keys to your car but the engine just won’t start.
When we see high Reverse T3, it often points to stress, inflammation, nutrient deficiencies, or poor liver function, all of which can interfere with healthy hormone conversion. Low selenium, for example, can slow this conversion dramatically since selenium is a key cofactor for the enzymes that turn T4 into T3.
Addressing those root causes, supporting the liver, replenishing minerals, managing stress, and healing the gut, can help restore the right balance. In some cases, practitioners may use natural desiccated thyroid (a blend of T3 and T4 from porcine sources) to support both forms directly, helping the body regain its rhythm.
The Iodine Connection: Why Salt Matters More Than You Think
When it comes to thyroid health, iodine is the unsung hero. It’s literally the building block of thyroid hormone, T4 has four iodine atoms, and T3 has three. Without enough iodine, your thyroid can’t make adequate hormone, and your pituitary starts shouting (via high TSH) for it to work harder. Over time, that can cause the thyroid to enlarge, forming a goiter.
Pregnant women are especially at risk because iodine is crucial for fetal brain and nervous system development. But even in adults, iodine deficiency can cause symptoms like fatigue, dry skin, weight gain, and feeling “off” despite normal labs.
Here’s the twist: in our modern quest for “clean eating,” iodine deficiency is creeping back. Many people have swapped iodized table salt for “natural” alternatives like Himalayan pink salt or Celtic Sea salt, which sound healthy but contain almost no iodine. Combine that with a fear of sodium, thanks to decades of messaging linking salt to heart disease, and we’ve created a perfect storm for iodine deficiency.
Yes, too much sodium from processed foods can raise blood pressure, but sodium itself isn’t the villain, it’s an essential electrolyte that keeps our nerves firing, our muscles contracting, and our hearts beating rhythmically. The real problem is the imbalance: too much processed sodium and too little potassium, magnesium, and iodine.
So, instead of avoiding salt altogether, focus on moderation and mineral balance, and make sure you’re getting iodine, whether through iodized salt, seafood, or a quality supplement when needed.
Bringing It All Together
Your thyroid is like the body’s thermostat, it sets the tone for metabolism, energy, mood, and even heart rhythm. But true thyroid health isn’t just about one lab number. A deeper look at TSH, Free T4, Free T3, Reverse T3, and thyroid antibodies, along with key nutrients like selenium, zinc, and iodine, can reveal what’s really going on under the surface.
If you’ve been told your thyroid labs are “normal” but you still don’t feel normal, it may be time to look beyond the basics. By understanding how your thyroid works, and what it needs to function optimally, you can take meaningful steps toward restoring balance, energy, and vitality.
References
- 50 Hypothyroidism Statistics: The State of Thyroid Patients [2024].
- Reverse T3 in Patients with Hypothyroidism on Different Thyroid Hormone Replacement
– PMC. - Selenium and Thyroid Disease: From Pathophysiology to Treatment – PMC.
- Natural Desiccated Thyroid for the Treatment of Hypothyroidism? – PMC.
- Zimmermann MB, Boelaert K. Iodine deficiency and thyroid disorders. Lancet Diabetes Endocrinol. 2015;3(4):286-95. PMID: 25591468.
