It is unclear if liver disease can directly cause hyperthyroidism. However, thyroid dysfunction may contribute to liver problems in some people.

Between 15% and 79% of people with untreated hyperthyroidism also have liver issues. In most cases, liver injury is mild. In time, 1% to 2% of them may develop hepatitis, which refers to inflammation of the liver.

In up to 83% of people, liver function returns to acceptable levels once they start taking medication to manage thyroid function. However, thyroid medications can sometimes contribute to liver problems. If this occurs, a doctor will likely review the person’s treatment options.

In this article, we explore the links between hyperthyroidism and liver disease.

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No studies have established that liver disease alone can directly cause thyroid problems. However, the two organs do work closely together, so a problem with one may affect the other.

The liver produces proteins that enable thyroid hormones to enter the bloodstream and travel throughout the body. Proteins from the liver also break down these hormones as waste when the body no longer needs them.

If the liver cannot perform this function, thyroid problems may result.

Yes, it can. Thyroid function is essential for the healthy working of most body systems, including the cardiovascular, nervous, and digestive systems. The liver is part of the digestive system.

A person may not notice any symptoms, but changes in liver function can show up in blood tests. In rare cases, severe liver damage can lead to hepatitis, or inflammation of the liver.

Liver problems may also worsen with hyperthyroidism if a person has one or more of the following:

Results of liver function tests show that people with a new diagnosis of thyroid disease often have reduced liver function. Often, when people start taking thyroid medication, the test results improve.

Research from 2021 suggests it is safe and beneficial for people with mild liver dysfunction to use thyroid medication.

A doctor will likely continue to monitor liver function over time to check whether the thyroid medication is having any adverse effects.

Learn more about liver function tests and what the results mean.

The following signs and symptoms may indicate liver problems:

Symptoms that may overlap with those of hyperthyroidism include fatigue and weight loss. Other signs of hyperthyroidism include:

People with a diagnosis of hyperthyroidism need regular appointments to monitor how their thyroid is responding to medication and any effects it may be having on their liver.

A doctor will also monitor thyroid levels while a person is taking medication, as too much medication can worsen thyroid problems.

Anyone who experiences new symptoms of liver disease needs to speak with a doctor, regardless of their thyroid status.

Possible causes of hyperthyroidism include:

There is a link between hyperthyroidism and liver function. Both systems support each other in maintaining overall health. When one reduces in function, it can affect the other.

Many people with a new diagnosis of hyperthyroidism also have reduced liver function. In most cases, this improves once the person starts taking thyroid medication.

However, in some cases, thyroid medication can worsen liver function. A doctor will continue to monitor liver function while a person receives thyroid treatment to ensure it does not damage liver health.