Irritable bowel syndrome (IBS) and thyroid disease can cause overlapping gastrointestinal (GI) symptoms. While there’s no evidence linking IBS with thyroid disease, disruptions to your gut health may impact your thyroid.

woman with IBS having her thyroid examined by a doctorShare on Pinterest
PeopleImages/Getty Images

IBS is a common GI condition that causes symptoms like abdominal pain and bloating. Researchers estimate that it affects between 10 to 15% of people.

Thyroid disease is also very common. It’s been estimated that more than 4.6% of people have hypothyroidism, and 1.2% have hyperthyroidism.

There’s no evidence that people with IBS develop thyroid disease more frequently or vice versa. But both IBS and thyroid disease are linked to a condition called small intestine bacterial overgrowth.

Learn more about IBS here.

The primary function of your thyroid is to produce the inactive hormone thyroxine (T4) and the active hormone triiodothyronine (T3). These hormones are collectively known as thyroid hormone. They influence how your body uses energy.

Some of their effects include increasing your:


Hyperthyroidism is when your body produces too much thyroid hormone. It can lead to symptoms like:

Learn more about hyperthyroidism.


Hypothyroidism is when your body doesn’t produce enough thyroid hormone. In Western countries, the primary cause is an autoimmune reaction. In some developing countries, iodine deficiency is also a common cause.

Symptoms can include:

Learn more about hypothyroidism.

Researchers continue learning more about how your gut health influences your thyroid. No definitive link between IBS and thyroid disease has been discovered, but in recent years, researchers have found increasing evidence that problems with your gut may affect your thyroid gland.

What’s the connection between gut health and your thyroid?

According to a 2022 review, there’s now compelling evidence that:

  1. GI conditions can lower levels of nutrients your thyroid gland needs to function properly.
  2. GI care can improve levels of these nutrients.
  3. GI conditions are at least 45 times more common than hypothyroidism.
  4. GI care can resolve some symptoms thought to be from thyroid dysfunction.
  5. GI health can influence the development of thyroid autoimmune disease.

IBS and thyroid health

Both IBS and thyroid disease can cause GI symptoms, but there’s no evidence to suggest that people with IBS develop thyroid disease more than other people.

In a small 2018 study from Nepal with 80 people, researchers found that in a group of people with IBS, 1% had hyperthyroidism, and 2.5% had hypothyroidism, which is similar to what would be expected in the general population.

An additional 16% of people had low levels of thyroid hormone that didn’t reach the definition of hypothyroidism. The researchers concluded that routine thyroid hormone testing for people with IBS is reasonable.

Thyroid gland and nutrients

An imbalance in gut bacteria has been linked to autoimmune thyroid disease and thyroid cancer.

The balance of bacteria in your gut has also been found to potentially influence the availability of nutrients required for optimal thyroid health. Researchers have found a strong link between thyroid disease and low levels of essential nutrients.

Essential nutrients for your thyroid include:

Your gut microbiome refers to all the microorganisms that live in your gut. Your gut is filled with trillions of bacteria and other small organisms too small to be seen without a microscope.

Some types of microorganisms are harmful to your health, but many help you digest your food and play a critical role in maintaining optimal gut health.

Learn more about your gut microbiome.

Small intestinal bacterial overgrowth (SIBO) happens when bacteria overgrow in your digestive tract. It can cause symptoms similar to IBS, like:

The cause of SIBO isn’t fully understood, but IBS and many other gut conditions are associated with SIBO.

In a 2017 study, researchers found high rates of SIBO in people with hypothyroidism. Hypothyroidism was even more associated with SIBO than:

  • intestinal surgery
  • low stomach acid
  • diabetes mellitis

In a 2018 study from Poland, researchers found people with thyroid disorders have a higher likelihood of developing SIBO.

Here are some ways you can keep your gut and thyroid health optimal:

  • see your doctor if you notice a new bump in the front of your neck
  • exercise regularly
  • eat a balanced diet filled with minimally processed foods
  • maintain regular bowel movements which may require additional fiber in your diet or supplementation
  • get tested for nutrient deficiencies that may affect your thyroid
  • minimize stress and incorporate relaxing activities into your daily routine
  • avoid foods that irritate your gut
  • eat more small meals rather than fewer large meals
  • chew your food thoroughly
  • consider taking a probiotic supplement or consuming more foods high in probiotics like yogurt, kimchi, or sauerkraut
  • drink plenty of fluids
  • get tested for food intolerances

Here are some frequently asked questions people have about thyroid conditions and IBS.

Does IBS cause thyroid disease?

There’s currently no evidence that IBS causes thyroid disease. But gut conditions that interfere with your ability to absorb certain nutrients may interfere with your thyroid health.

Does thyroid disease cause IBS?

There’s also no current evidence that thyroid disease causes IBS. Thyroid disease can cause symptoms that overlap with IBS, like constipation or diarrhea.

Will treating my IBS cure my thyroid disease?

Treating IBS hasn’t been proven to be able to cure thyroid disease. But there’s compelling evidence that taking care of your gut health may help improve thyroid function.

How is IBS treated?

IBS doesn’t have a cure, but many people can achieve relief with a combination of dietary changes or lifestyle changes. If these aren’t effective, your doctor may recommend medications like anti-constipation drugs or medications to control muscle spasms in your gut.

Learn more about IBS treatment.

Although researchers haven’t found a direct connection between IBS and thyroid disease, a growing amount of evidence suggests a connection between gut health and thyroid disease.

IBS and thyroid disease are both associated with SIBO, although more research is needed to understand the connection.

Taking care of your GI health can improve many aspects of your health. Your doctor may recommend trying medications if dietary changes and lifestyle changes don’t resolve your IBS symptoms.