The lesser-known, more lethal thyroid disease

Plus, how to stop it before it turns deadly


I write about thyroid disease a lot—and for good reason.

As one of your body’s main energy regulators, this tiny organ plays a vital role in most of your biological functions. Metabolism may be its main role. But it also impacts mood, memory and attention, bowel regularity, hair and skin texture, and even your heart health and cholesterol… the list goes on and on.

Your thyroid keeps your whole body running. And like an engine, it can run too slow or too fast.

In my experience, I’ve found that a majority of my patients are only familiar with the risks of hypothyroidism, or an underactive thyroid. But hyperthyroidism, or an overactive thyroid, is every bit as dangerous. And knowing what to look for is every bit as critical.

First, a few thyroid basics…

Your thyroid is a tiny butterfly-shaped gland located in your neck. And it generates two main hormones—thyroxine (T4) and triiodothyronine (T3). These hormones influence metabolism, body temperature, heart rate, protein production, and more.

Maintaining optimal levels of T4 and T3 requires thyroid-stimulating hormone, or TSH. Your brain’s pituitary gland generates this hormone, on the orders of your hypothalamus, when levels of either T4 or T3 are too low.

So if your thyroid isn’t generating enough T4 or T3 hormones, the body produces more TSH to stimulate the thyroid. So high TSH levels will often be one of your first signs of hypothyroidism.

On the other hand, if your thyroid is overproducing hormones, you’ll have high hormone levels in your bloodstream. Since your body is detecting the presence of hormones, it doesn’t trigger your pituitary gland to make more—which results in low (or nonexistent) TSH levels. This is one of the primary biomarkers of hyperthyroidism.

But what about physical symptoms? I’ve covered the telltale signs of hypothyroid many times before—weight gain, fatigue, low body temperature, and depression, just to name a few. But the red flags of an overactive thyroid are quite different.

Patients with hyperthyroid are more likely to struggle with:

  • Abnormally protruding, or “bug” eyes—called exophthalmos
  • Diarrhea
  • Excess hunger
  • Excess sweating
  • Fatigue and restlessness
  • Hair loss
  • Insomnia
  • Nervousness and panic attacks
  • Palpitations
  • Tremors
  • Weakness

Of course, thyroid problems often go hand-in-hand with weight problems. Hypothyroidism tends to cause weight gain. And hyperthyroidism can lead to weight loss, from a metabolism in overdrive.

And while that may sound like a blessing in disguise, I can assure you it’s anything but.

A hidden culprit behind obesity and heart disease

While it sounds counterintuitive, hyperthyroidism can actually lead to obesity. Not in the throes of the disease. But after treatment starts, many patients will actually have a harder time managing their weight than people with hypothyroid.

In fact, more than half of hyperthyroid patients will become obese within two years after diagnosis and treatment.1

But that doesn’t mean you should skip out on treatment in favor of a smaller waistline. Ignoring the signs of an overactive thyroid sets you up for much bigger trouble behind the scenes. Previous research has linked high T4—a warning sign of hyperthyroidism—with atrial fibrillation (a dangerously irregular heartbeat) and sudden heart death.2-3

And newer research shows that your thyroid hormone levels don’t even have to be particularly high to pave the way to lethal problems.

In fact, this research showed that even free T4 levels at the upper end of the “normal” range are linked to hardened arteries and cardiovascular death. This held true even after researchers accounted for other heart-related risk factors, like elevated cholesterol and high blood pressure.

This latest finding came from the prestigious Rotterdam Study. Researchers looked at subjects’ levels of both thyroid stimulating hormone (TSH) and free T4. Then they looked for links between these levels and events (including death) that were attributed to atherosclerosis (the hardening and narrowing of the arteries).

Follow up lasted nine years on average. And the data revealed some pretty concerning trends.

Subjects with rising free T4 levels were:

  • Twice as likely to have high coronary artery calcification (CAC) scores—a surefire indication of hardening arteries.
  • 87 percent more likely to have a heart event linked to atherosclerosis.
  • More than double the risk of death related to atherosclerosis.4

Even modestly elevated free T4 levels can be a dangerous red flag. And sadly, most mainstream doctors don’t even bother to test for them. And when they do, they don’t really know what to look for in order to properly evaluate your thyroid.

Needless to say… that’s a real problem.

Four tests that tell you what you really need to know about your thyroid

There are more than 300 symptoms associated with thyroid disease—and I look for every single one during a patient evaluation.

But obviously, most doctors aren’t spending this much time with their patients. So it’s simple to see how easy it is for thyroid disease to go underdiagnosed and undertreated. Especially considering conventional medicine remains so stubbornly committed to treating numbers, instead of  people.

Most conventional doctors will usually just check your thyroid stimulating hormone (TSH) level and call it a day. But that’s just not enough.

Below are the four tests I recommend to screen the levels that really matter so you and your doctor can determine a plan of action specific to your needs:

1) Thyroid panel. This is a blood test, and it should include measurements for TSH, free T4, T3, reverse T3, thyroid autoantibodies, and TBG (or thyroxine binding globulin, a protein that that moves thyroid hormone through the body).

Based on blood results, you may have hyperthyroidism if:

Your levels exceed the following measurements for:

  • Free T4: 1.8 ng/dL (nanograms per deciliter)
  • Free T3: 4.2 pg/mL (pictograms to milliliter)

Your levels are below the following measurements for:

  • TSH: 0.2 mU/L (milliunits per liter)

  • Reverse T3
    : 10 ng/dL(nanograms per deciliter)—though it can also read as normal or elevated
  • TBG: 1. 1 mg/dL (milligrams per deciliter)

  • Thyroid Antibodies
    : 1 IU/mL (international
    units per milliliter)—though it can also read as normal or elevated

2) Thyroid ultrasound. If your thyroid panel shows suppressed TSH and/or high free T4 or T3, your doctor should send you for an ultrasound to rule out cancer. While it’s not very common, it does happen.

This procedure is safe and painless, using sound waves to produce images of your gland. These are typically used to more closely observe lumps (or nodules) found during a routine physical exam.

3) Thyroid scan. This test measures your thyroid structure. It uses weak, radioactive iodine, which is either injected intravenously, swallowed as a pill, or inhaled as a gas. This iodine then collects in the thyroid which helps measure your gland’s activity over the course of a few hours.

Pictures of your neck are then taken with a special camera to capture images of your thyroid gland from three different angles. These images will show the outline, shape, size, and position of your thyroid gland, as well as any indicators of lumps or inflammation.

4) Radioiodine uptake test. This test measures your thyroid function. Like the thyroid scan, this noninvasive test also uses radioactive iodine, but doesn’t produce a medical image. Instead, a probe is positioned over your thyroid gland to measure the amount of radioactivity.

If it appears that your gland is taking up a lot of iodine, this can be an indicator of autoimmune hyperthyroidism, like Graves’ disease (according to the Mayo Clinic). If it’s hardly taking up the iodine, but other testing indicates hyperthyroidism, it’s often the result of thyroiditis or an inflamed thyroid.

This method takes a bit longer than the thyroid scan. Typically, after the iodine is administered, your levels are measured twice within a 24 hour period (typically at hour 6 and hour 24).

If these tests confirm you indeed have hyperthyroidism, you need to take the appropriate steps to get it under control—before it does any more damage.

You action plan for a hyperthyroidism diagnosis

There are a few different ways to deal with an overactive thyroid—but unfortunately, they all come with their own set of problems.

One option is to take anti-thyroid medication. But these drugs pose a serious threat to your liver and can lead to severe damage—even death. And they’re not necessarily a long-term solution, especially for more persistent forms of thyroid disease.

That leaves you with two more options: You can ingest very high doses of radioactive iodine that will shrink and destroy your thyroid. Or you can have surgery to remove your thyroid entirely.

There are pros and cons to each of these approaches, but the result will be the same: You will never have a functioning thyroid gland. And you’ll have to be on thyroid replacement medication for the rest of your life.

That’s the bad news. The good news is, with careful monitoring and the right medications, you can manage quite well over the long term. So, what exactly are the right medications?

Bioidentical replacement is always best

When it comes to thyroid replacement, almost all conventional doctors recommend Synthroid®—a synthetic form of T4. The problem is, your body must convert T4 into T3, which is the active form of the hormone. But as we age, we lose our ability to convert T4 to T3.

I do things differently. I use Nature-Throid®, Armour® Thyroid, or a compounded version of thyroid hormone. These contain a bioidentical mixture of T3 and T4.

These products are derived from the thyroid of animals—most commonly, pigs. So if that makes you squeamish, then this type of hormone therapy may not be for you.

But if you let that stop you, you’ll be doing your body a major disservice. Because this is the most natural, balanced, and effective form of thyroid replacement out there. (And remember, hormones are all about balance. If one is off, it can take the others with it—and that will seriously impact both how you function and feel.)

The takeaway I want to make absolutely clear today: there’s much more at stake when it comes to thyroid problems than just your weight. Hyperthyroidism, in particular can and will kill you if it’s left untreated. But unfortunately, a lot of doctors aren’t doing their due diligence.

If you suspect your thyroid isn’t functioning properly, don’t be afraid to demand more. Because anything less is just plain bad medicine.

What causes hyperthyroid?

The single most common cause of an overactive thyroid is Graves’ disease.

This autoimmune disease triggers the release of antibodies that attack your thyroid and stimulate the overproduction of T4. (These same antibodies can also attack the tissue behind your eyes and on your skin, most commonly over your shins.) Like most autoimmune disorders, doctors aren’t really sure what causes it—but genetics and gender (women are much more susceptible) definitely play a role.

Thyroid nodules are another possible cause. These are noncancerous lumps that can enlarge your thyroid. And while they don’t all generate excessive T4, having one or more that do can lead to hyperthyroidism.

Finally, there’s thyroiditis—or an inflamed thyroid gland. This condition doesn’t always have obvious origins. (Though it’s not uncommon post-pregnancy.) And it causes stored thyroid hormones to leak from the gland into your blood stream, leading to hyperthyroid symptoms.


  1. Brunova J, et al. S Afr Med J. 2003 Jul;93(7):529-31.
  2. Baumgartner C, et al. Circulation. 2017 Nov 28;136(22):2100-2116
  3. Chaker L, et al. Circulation. 2016 Sep 6;134(10):713-22.
  4. Bano A, et al. Circ Res. 2017 Dec 8;121(12):1392-1400.