• Glenn Rothfeld, MD

What Most Doctors Get Wrong About Thyroid Treatment

Do you ever feel completely exhausted with no clear explanation as to why?

You can be eating right and getting plenty of sleep. You can be avoiding meds that make you drowsy, and knocking back more cups of coffee than you can count. And yet… zzzzzzzzzz.

You’d be right to think that it could be your thyroid. After all, the hormones coming out your thyroid gland control the energy that powers every cell in your body.

The thyroid is responsible for speeding up or slowing down the heart, raising or lowering body temperature, and controlling the rate at which calories are burned. Your thyroid even controls how fast the food you eat moves through your digestive tract!

It also affects your muscle and joint function, nervous system, and even hair growth.

But despite the thyroid’s many jobs, the vast majority of conventional doctors misunderstand it. They play a numbers game and take only a superficial look at how it’s working, which leaves so many patients experiencing symptoms of hypothyroidism with no relief.

So, I’d like to share how to REALLY “get the most” out of your thyroid gland. But first, I need to explain a bit about its function.

What your doctor gets wrong about your thyroid test

The thyroid really fascinates me. So much so, that I wrote a book about it.

I’ve studied this gland for decades, and I’m eager to share some of what I’ve learned with you—especially if you’ve been feeling a bit “down and out” and haven’t been able to figure out why.

Your butterfly-shaped thyroid gland sits in front of your throat and mostly produces the hormone T4.

When your pituitary gland senses that more thyroid activity is needed, it secretes something called thyroid-stimulating hormone (TSH), which then travels to the thyroid and delivers a message to release more T4 into the bloodstream.

At the most basic level, T4 consists of a tyrosine molecule attached to four iodine atoms. But tyrosine is largely inactive when it’s got four iodine atoms attached to it. So cells containing an enzyme called deiodinase spring into action to remove one iodine atom, thereby transforming it into T3, which is tyrosine and three iodine atoms.

T3 is the primary active thyroid hormone in the body. It’s the one your body can actually use.

The prevailing medical wisdom is that if your TSH is too high, your doctor will give you a prescription for T4 (most commonly levothyroxine, a.k.a. Levoxyl or Synthroid), and if your TSH is low, they’d say you don’t need any more thyroid.

But if that were actually true, I would not have literally hundreds of patients come into our office with normal or low TSH levels—many of whom are already on T4 therapy—who are still tired, gaining weight, brain-fogged, muscle-aching, constipated, dry-skinned, depressed, among a myriad of other low-thyroid symptoms.

It turns out that the prevailing “wisdom” is dead wrong, and it reflects the poor understanding that most doctors have of how thyroid function actually works.

Why thyroid troubles can sabotage your mood

Tyrosine, the major component of thyroid hormones T3 and T4, is the same amino acid used to make the neurotransmitters dopamine and norepinephrine.

This is one of the reasons why thyroid function and mood are intimately related and we are starting to see research supporting the use of T3 therapy in depression. I applaud this, as many cases of depression are associated with decreased thyroid hormone binding or transport into the cell, or production of rT3 rather than active T3.

Even some cases of bipolar illness have been treated successfully using T3 therapy.

A rotating cast of players

Not all deiodinase enzymes are alike. The major one, called D1, converts the T4 from the bloodstream into active T3, and can be found in almost all cells of the body. Another type of deiodinase, called D3, converts T4 into something called reverse T3, or rT3. (There’s also yet another type of deiodinase, D2, which will come into play in a little bit if you stick with me.)

I call rT3 the “Bizarro T3.” If you've ever read Superman comics, you know that there was a character called “Bizarro Superman” who had powers just like Superman’s, but they always had the opposite result.

In the same way, T3 speeds up metabolism, but rT3 slows it down. rT3 does this by suppressing D1 activity (which interferes with the activation of T4 to T3), competing for and blocking the binding sites for T3 on the cells, and lowering the ability of T3 to be transported into the cell. So, the more rT3 and less active T3 produced by the cells from T4, the more sluggish your metabolism, and the more "classic hypothyroid" symptoms that result.

But say your doctor ignores this nuance and just treats the “low-thyroid” symptoms by giving you more T4… In this case, even more rT3 is produced, more T3 binding sites are blocked, less active T3 is available in the cells, and symptoms actually worsen!

Sabotaged by stress

If you’re generally healthy, you can count on two things: relatively little D3 activity, and your body not producing much rT3.

Unfortunately, almost anything that stresses your body will turn on the rT3 mechanism. Every day, I see this happen with common stressors like infections (including Lyme disease and Epstein-Barr virus); toxins such as heavy metals, pesticide residues and mold-derived mycotoxins; and chronic pain syndromes. These conditions “down-regulate” the D1 and “up-regulate” the D3, leading to much lower levels of active T3 in the cells, and symptoms worsening. In the case of chronic pain, narcotic pain relievers may lower the feeling of pain, but they also lower D1 activity and ultimately worsen symptoms.

Most illnesses associated with inflammation (like autoimmune disease and allergy-associated conditions) have also been proven to involve lower activation of T3 and a slower metabolism, leading to fatigue and other chronic symptoms. Chronic dieting has a particularly bad effect on thyroid metabolism. Studies show that persistent dieting radically lowers the amount of T3 in the cells, and this condition can persist for years. That’s why if you diet repeatedly, you may notice an increasingly decreased ability to lose weight—even with extreme dieting— because your cellular metabolism has been lowered due to the lowered T3.

The effect is even worse if you have insulin resistance or type 2 diabetes, since blood sugar and insulin elevations are associated with much lower tissue levels of T3.

Again, giving levothyroxine does nothing since the enzyme that activates it has been down-regulated. The result? You and your doctor both think that “thyroid doesn’t work for weight loss.” And that’s not exactly true.

Why you’ve got to do a deeper dive

It’s clear that T4 is inadequate for treating symptoms of low thyroid if you have normal or low TSH but have been told by your doctor that your thyroid is fine. And maybe your thyroid IS fine, technically. Maybe your pituitary gland is fine, too. But that doesn’t mean you’re getting sufficient amounts of the active thyroid hormone you need where you need it—in the cells of your tissues.

The science gets a little complicated here, but stick with me.

As I mentioned, there are different types of deiodinase enzymes that remove iodine atoms from your thyroid hormones to convert the inactive T4 into active T3.

Well, your pituitary has very little D1, no D3, and plenty of D2. And since D2 is 1,000 times more efficient in converting T4 to T3 than D1, your pituitary will remain rich in active T3 and TSH will not increase, while the other tissues of your body are starved of T3!

I know that’s quite an alphabet soup to swallow, but it all comes down to this: your pituitary gland can’t necessarily recognize that your body needs the active thyroid hormone anywhere other than in the gland. To make matters worse, the same stressful conditions (infections, inflammation, pain, toxin exposure, etc.) that can deprive your tissues of T3, actually make the pituitary MORE efficient in producing it!

Just by looking at the normal or low TSH produced by that pituitary, most doctors will mistakenly conclude that no thyroid support is needed, and you will continue to suffer from hypothyroid symptoms.

You’re not fine, but you will be

At the Rothfeld Center, we’ve found that a time-released form of T3 (made for us by compounding pharmacies) gets the best results in conditions of stress-induced low cellular thyroid function.

By supplementing with it orally, you can deliver it straight to the tissues, where it’s severely lacking, and bypass the glandular process that’s gone sideways. For cost reasons, we’ll sometimes use the regular pharmacy T3—called liothyronine (brand name Cytomel)—but its activity span is generally too short and can be too jarring on the metabolism. It can be tricky to get the right dose of time-released T3, as there can be a lot of individual variation in the activity of those deiodinase enzymes, and since T4 and TSH levels are not useful here, we often have to go on symptoms and clinical judgement (sometimes aided by basal body temperatures).

But in the end, when all is said and done, it’s immensely gratifying to have patients get relief from low-thyroid symptoms. Especially after a lifetime of being told, “It’s not your thyroid.”

Primary source referenced for this blog:

Holtorf, Kent. "Peripheral thyroid hormone conversion and its impact on TSH and metabolic activity." Journal of Restorative medicine 3.1 (2014): 30-52.’’