Symptoms of a Hashimoto’s Flare-Up and What to Do About Them

Something may be interfering with your medication

A flare-up of Hashimoto’s disease can make you have hypothyroidism symptoms even when you’re being treated for it. Most of the time when this happens, it’s because you’re not getting enough of the thyroid replacement hormone used to treat the condition, which is most often levothyroxine (T4). Either your dose needs to be adjusted to avoid breakthrough Hashimoto’s symptoms, or something is interfering with how your body uses the medication.

What Is Hashimoto's Disease?

Hashimoto’s disease, which is also called Hashimoto’s autoimmune thyroiditis, is an autoimmune thyroid disease in which the immune system mistakenly identifies the thyroid gland as a dangerous pathogen and attacks it. This impairs the thyroid's ability to produce hormones. Hashimoto’s is the most common cause of hypothyroidism in the United States.

Young woman with sore throat

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Several different things can interfere with your thyroid function or levothyroxine treatment and trigger a flare-up of Hashimoto’s disease, including:

  • Some medications or supplements
  • Certain dietary nutrients
  • High stress levels
  • Incorrect medication dosage

In order to treat your Hashimoto's more effectively, it's important to figure out what's causing your symptoms to act up.

Medications or Supplements

A lot of common medications and nutritional supplements can interfere with how your body absorbs synthetic levothyroxine. Some drugs can also impact the way your body metabolizes thyroid medication. In either case, your body doesn’t get enough of the drug to keep your autoimmune thyroid disease symptoms at bay. 

According to studies, including one of more than 5,000 people on thyroid hormone therapy, numerous drugs can interfere with levothyroxine absorption, including:

Drugs that can alter the way your body metabolizes levothyroxine include:

Nutritional supplements that can interfere with thyroid hormone replacement include:

  • Calcium carbonate
  • Iodine
  • Iron
  • Multivitamins containing calcium and iron
  • Supplements containing soy extracts


Stressful events or chronically high stress levels can aggravate your immune system and increase autoimmune activity. Research has linked stress to lower thyroid hormone levels as well. Given this one-two punch, it’s possible that stress could cause a Hashimoto’s flare-up.

Don’t just assume your flare-up is stress-related, though. If you have ongoing symptoms of Hashimoto’s, let your healthcare provider know so they can check for other possible causes.

Incorrect Dosage

You may be having Hashimoto’s symptoms because you’re not on the right dosage of levothyroxine. When you first begin treatment for hypothyroidism, it’s common to need a few adjustments to your dosage before you reach a symptom-free state.

Early on, or after a dose adjustment, your healthcare provider may test your thyroid hormone levels every six to eight weeks. Once your ideal dosage is reached, you may only need to be tested once a year.

However, if you begin having symptoms of low thyroid hormone, you may need a higher dosage and the associated regular testing until symptoms are once again under control.

Why Treat With T4 Instead of T3?

T4 is an inactive hormone that your body converts to T3 (triiodothyronine), which is the active form. Healthcare providers prescribe T4 to allow your tissues to make that conversion when and where it’s needed. This approach is effective for many people with thyroid disease, but evidence suggests some people's bodies don’t convert T4 to T3 efficiently, so they may need to be treated with synthetic T3 (liothyronine) in addition to T4.


In a Hashimoto’s flare-up, you’ll begin having symptoms of hypothyroidism, which include:

  • Fatigue
  • Weight gain
  • Frequently feeling cold
  • Dry skin and hair
  • Muscle and joint aches
  • Depression
  • Constipation
  • Memory problems
  • Irregular menstrual periods
  • Slow heart rate

Fatigue and Thyroid Disease

One of the primary symptoms you’re likely to experience during a Hashimoto’s symptom flare-up is fatigue. The fatigue of thyroid disease isn’t like ordinary tiredness and may have a significant impact on your life.

When to See a Healthcare Provider

Flare-ups shouldn't happen when you’re on the correct dose of levothyroxine. Any time you have a resurgence of Hashimoto’s symptoms, you should let your healthcare provider know. They may want to change your dosage, look for things that could be interfering with your treatment, or test for other potential causes of your symptoms.


Treatment for a Hashimoto’s flare-up depends on what’s behind the increase in symptoms.

Timing Is Key

If a medication or supplement is hampering your body’s ability to utilize levothyroxine, you may need to change the timing of your medications. Sometimes, simply taking the interfering medication at least an hour after your levothyroxine will allow your body to fully absorb the medication. If you take your thyroid drug in the morning, you may have better luck taking it at night.

The timing of your thyroid medication can be affected by a lot of different factors, including other drugs you take and even what you eat for breakfast, so before changing the time of day you take your levothyroxine, talk to your healthcare provider about it.

Other Approaches

There are other ways to manage a Hashimoto's flare-up:

  • In some cases, your healthcare provider may advise you to stop a medication or replace it with a different drug.
  • With proton pump inhibitors, research shows that taking an oral levothyroxine solution instead of tablets may improve absorption.
  • If you have a nutrient deficiency, you may need to take supplements or change your diet to bring levels up and improve your thyroid function.
  • For stress-related thyroid flare-ups, some preliminary research suggests that mindfulness meditation may improve immune system function.

A Word From Verywell

Regardless of what’s causing your Hashimoto’s symptom flare-up, a trip to the healthcare provider's office is a good place to start. With their help, you can investigate possible causes of your low T4 levels and implement the right solution. Successful thyroid disease treatment is a balancing act and sometimes tricky, but once you get things back in balance, you should be feeling and functioning better again.

11 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Adrienne Dellwo
Adrienne Dellwo is an experienced journalist who was diagnosed with fibromyalgia and has written extensively on the topic.