Hashimoto’s Thyroiditis: The Strange-Sounding Condition You Can Have Without Realizing It 

5 facts that may surprise you
magnified illustration of a thyroid being attacked by blue antibodies inside a person's neck

You’re tired all the time. You’ve gained weight. You can’t stand the cold. And you’re looking kind of puffy.

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A blood test reveals your thyroid is underactive. Could it be Hashimoto’s thyroiditis?

In the United States, Hashimoto’s is the top cause of hypothyroidism, or shrinking production of thyroid hormone.

“Hashimoto’s is an autoimmune condition that can strike at any age, but is most often diagnosed between ages 40 and 60,” says endocrinologist Mary Vouyiouklis-Kellis, MD.

“It is eight times more common in women, but affects men and children, too. Family history plays a big role.”

Here, she shares five surprising facts about the condition also known as chronic lymphocytic thyroiditis.

1. Hashimoto’s is not as scary as it sounds.

Read patient blogs about Hashimoto’s thyroiditis, and you’ll find it portrayed as a frightening disease.

“In reality, Hashimoto’s is a benign, highly treatable condition,” stresses Dr. Kellis. “Taking thyroid supplements will improve most of your symptoms, and most people do quite well on them.”

The bow-tie-shaped thyroid gland, at the base of your throat, secretes a hormone called T4 (thyroxine). Your body must convert T4 to T3 (triodothyroinine) to maintain your metabolism, and regulate your body temperature, heart and other vital organs.

“Sometimes, when you’re first diagnosed with Hashimoto’s, you can still produce some thyroid hormone,” she notes. “As the years go by, you may produce less hormone, so your doctor will gradually increase your dose of medication,” she says.

Those with celiac disease or who have had gastric bypass surgery must be carefully monitored because they may not absorb thyroid medication properly, and their levels can fluctuate.

2. Hashimoto’s often goes undiagnosed.

Hashimoto’s prompts your body to create antibodies that attack and inflame the thyroid.

But doctors often don’t check blood for the telltale antibodies because all hypothyroidism is treated the same way.

“Many people are never told they have Hashimoto’s,” says Dr. Kellis. “But at the end of the day, if your thyroid is underactive, it’s usually Hashimoto’s thyroiditis,” she says.

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Other, less common, causes of hypothyroidism include:​

  • Surgical removal of the thyroid.
  • Radiation to the neck.
  • Use of certain psychiatric, heart, cancer or rheumatologic medications.

So knowing whether or not you have Hashimoto’s may be a moot point — unless you’re a woman trying to conceive.

“Hashimoto’s carries a slightly higher risk of miscarriage, so you’ll need the blood test for thyroid antibodies,” says Dr. Kellis.

“You may need to take thyroid supplements, even if your TSH (thyroid-stimulating hormone) levels are normal.”

3. Your thyroid isn’t always to blame for fatigue and weight gain.

“Many patients with Hashimoto’s complain of weight gain, fatigue and brain fog,” says Dr. Kellis.

But the thyroid’s relationship to your metabolism is complicated. Other hormones and proteins also come into play.

“Hashimoto’s can often be associated with some weight gain — it’s mostly salt and water weight, which is why you look puffy,” she says.

“However, the weight gain seen with Hashimoto’s thyroiditis is usually less dramatic than the weight loss seen with autoimmune hyperthyroidism (Graves disease).”

If you’re still fatigued after thyroid hormone levels are optimized, your endocrinologist will look for other causes.

For example, having Hashimoto’s puts you at risk for other autoimmune conditions that contribute to fatigue, including:

If fatigue persists, let your doctor know so they can help rule out other conditions that cause fatigue — such as sleep apnea, which is often undiagnosed.

4. Thyroid medication only works if taken the right way.

The most common medication for Hashimoto’s is levothyroxine (Synthroid®, Levothyroid®, Levoxyl®), or T4.

Because some people are unable to convert T4 to T3, doctors may prescribe a combination of T4 and T3.

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The addition of T3 can help patients who also have mood disorders like depression. But while some studies suggest that adding T3 to T4 may help weight loss, “it is not a skinny pill,” says Dr. Kellis.

Both thyroid hormone medications — T4 and T3 — must be taken one hour before any other prescription pills, and three to four hours before multivitamins or iron supplements.

“Even taking them with orange juice or coffee can interfere with thyroid supplement absorption,” she says. “We recommend taking them with water only.”

Levothyroxine is so safe that it can be taken during pregnancy.

But your doctor must check blood levels periodically to make sure thyroid stimulating hormone (TSH) levels stay within mid-normal range (the goal: < 2.5).

If your dose is too high, symptoms can swing the other way — into hyperthyroidism, causing insomnia, anxiety, weight loss and heat intolerance.

5. You probably won’t need to modify your diet.

Avoiding refined sugar will be helpful, as eating sugar can often contribute to fatigue,” says Dr. Kellis.

And if you have, or are suspected to have, celiac disease, you’ll want to avoid gluten.

But you won’t need to steer clear of cruciferous vegetables or soy — both nutrition powerhouses. They can be eaten in moderation.

Doctors recommend eating one or two Brazil nuts per day rather than taking supplements to get your selenium.

Iodine supplements are not advised. While women need iodine during pregnancy to prevent goiter, most U.S. foods are already fortified with it.

“As long as you’re being treated and followed by a doctor, and getting your blood levels checked, there’s no reason to modify your diet,” she says.

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