People with multiple sclerosis appear to have higher rates of thyroid problems than the general population. The link isn’t clear, but shared pathways and MS medication side effects may play a role.

MS is an autoimmune disease where your body attacks healthy myelin cells in the spinal cord and brain. Myelin is the protective fatty layer that covers nerve cells. People with MS often develop:

  • vision problems
  • movement and muscle problems
  • changes in sensation

Thyroid disease affects the butterfly-shaped gland at the front of your neck. Its primary role is to produce hormones that influence your metabolism.

Although the connection between these two conditions is still under investigation, it’s well established that some medications used to treat MS can affect the thyroid gland and the two conditions may share a physiological pathway.

Read on to learn more about the link between MS and thyroid problems.

There appears to be an association between multiple sclerosis and thyroid disease, although the exact link isn’t clear.

MS is thought to be an autoimmune condition. It’s estimated to affect nearly 1 million people in the United States and symptoms often onset between ages 20 and 40.

Thyroid disease is classified as hypothyroidism if your body produces too little thyroid hormone and hyperthyroidism if your body produces too much thyroid hormone.

The most common cause of hypothyroidism is the autoimmune condition called Hashimoto’s disease. The most common cause of hyperthyroidism is another autoimmune condition called Graves’ disease.

People with one autoimmune disease tend to be more likely to develop another, and about 25% of people with MS develop another autoimmune condition.

The relationship between MS and thyroid problems isn’t well understood. Some research suggests a correlation, but research identifying the incidence of overlap between the two diseases is not consistent.

Processes mediated by thyroid hormone are essential for the production of myelin. Additionally, researchers have identified some shared genes that may be associated with MS and other autoimmune conditions like Hashimoto’s disease. Research also suggests that thyroid hormone levels may influence the type and progression of MS.

In a 2024 study from Iran, researchers examined the prevalence of antibodies that suggest autoimmune thyroid disease in 73 people newly diagnosed with MS and 72 without MS. They found increased rates of thyroid antibodies among people with MS compared to the control group.

In a 2018 study, researchers found evidence of a plausible shared pathway between MS and Hashimoto’s thyroiditis involving shared dysregulation of anti-inflammatory molecules.

In another 2024 study, researchers found some slight evidence of a positive causative relationship between thyroid-stimulating hormone (TSH) levels and MS but didn’t see a significant causal relationship between hypothyroidism or hyperthyroidism and MS. TSH is a hormone produced by your thyroid gland that stimulates the release of thyroid hormone.

In reverse, the researchers did not find a causal relationship between MS and TSH levels, hypothyroidism, or hyperthyroidism.

In yet another 2024 study, researchers also found evidence of a higher prevalence of TSH alteration among people with MS, suggesting that people with MS might be at an increased risk for thyroid dysfunction.

The research is still new in uncovering these correlations, and it’s not clear how significant these changes are in managing MS or thyroid disease.

Some of the medications used to treat MS may increase your risk of thyroid dysfunction.

In a previous 2020 study, research found that 26% of 126 people with MS treated with alemtuzumab developed autoimmune thyroid disease. Previously, studies have reported autoimmune thyroid disease in up to 40% of people with MS treated with alemtuzumab.

A 2020 study from Egypt reported thyroid disease in 40% of people with relapsing-remitting multiple sclerosis.

The researchers observed a significantly higher prevalence of autoimmune thyroiditis in people treated with interferon beta-1b compared to other disease-modifying drugs. They also observed a significantly higher prevalence of infectious thyroiditis (a severe form) in people treated with the medication fingolimod.

MS symptoms

Common MS symptoms include:

Hypothyroidism symptoms

Symptoms of hypothyroidism can include:

Hyperthyroidism symptoms

Hyperthyroidism symptoms can include:

Researchers have found strong evidence that multiple sclerosis may be linked to:

Risk factors for Hashimoto’s disease include:

MS hasn’t specifically been linked to thyroid cancer, but thyroid cancer symptoms can include:

  • a lump in the front of your neck
  • feeling like shirts fit tighter in the collar
  • voice changes such as hoarseness
  • trouble breathing
  • pain when swallowing
  • feeling like something is stuck in your throat
  • swollen throat lymph nodes
  • a persistent cough

It’s suggested to visit a healthcare professional if you notice early symptoms of MS, such as:

  • trouble with movement
  • vision changes
  • numbness or tingling with an unexplained cause

Make an appointment to see a doctor if you have symptoms of thyroid disorder, such as increased fatigue or unexplained weight changes.

Research suggests that there may be a connection between MS and thyroid disease. The exact connection isn’t clear, but a shared pathway and MS medication side effects may play a role.

It’s important to see a doctor if you develop early symptoms of either condition. Receiving an early diagnosis allows you to receive treatment as soon as possible.