How Thyroid Disease Causes Dry Mouth

If you have thyroid disease, chances are you also have persistent thyroid disease dry mouth (dry mouth).

In fact, while there are many causes of dry mouth, one study found that about half of people diagnosed with dry mouth have thyroid disease.

To complicate matters, treatment of thyroid disease can also trigger xerostomia. Dry mouth is not life-threatening, but it can make swallowing difficult, lead to bad breath, and even lead to complications such as tooth decay and oral infections.

This article explains the link between thyroid disease and dry mouth. It also points to specific thyroid conditions that most commonly cause dry mouth and how to relieve discomfort.

saliva link

One of the many effects of thyroid disease is reduced saliva production and release from the salivary glands. This can cause dry mouth. For example, thyroid patients who spit up may not fully replenish their saliva until hours later.

This is thought to be related to a slowed metabolism, or an underactive thyroid, associated with hypothyroidism. Untreated or partially treated hyperthyroidism can also cause dry mouth, but the cause is unknown. Hyperthyroidism is a state of an overactive thyroid.

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Hashimoto’s disease

Thyroid disease

While dry mouth is most commonly associated with hypothyroidism, research suggests that it can also occur with a variety of thyroid conditions, including those that cause hyperthyroidism. Some thyroid disorders associated with dry mouth include:

  • Hashimoto’s Thyroiditis (HF): HF is an autoimmune disease that causes hypothyroidism due to decreased thyroid function.
  • Subacute thyroiditis: Thyroid inflammation caused by granulomatous thyroiditis, HF, inflammation, drugs, or infection can lead to hypothyroidism or hyperthyroidism.
  • Subclinical hypothyroidism: People with early-stage hypothyroidism or hyperthyroidism may have mild or insignificant effects, including dry mouth.
  • Grave’s disease: A common form of hyperthyroidism, Grave’s disease can cause weight loss, hyperactivity, insomnia, and dry mouth.

Eating well during cancer treatment, even with dry mouth


Some thyroid disease treatments can also cause dry mouth:

  • Radiation therapy: Radiation therapy, often used to treat thyroid cancer, can affect the thyroid gland and may damage the salivary glands, reducing the amount of saliva.
  • Radioactive iodine therapy: Radioactive iodine is used to treat thyroid cancer and some types of hyperthyroidism, which often lead to hypothyroidism and decreased salivary gland function.
  • Thyroid hormone replacement therapy: Often, treating hypothyroidism can improve dry mouth. But in some cases, excess thyroid hormone replacement can also cause dry mouth.
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In addition to the obvious, the effects of dry mouth include:

  • bad breath
  • Tooth decay, gum disease*
  • Chapped, cracked or cracked lips*
  • Decreased ability to speak fluently and comfortably
  • reduce enjoyment of food
  • Impaired ability to chew and swallow food
  • Oral infections, mouth ulcers*

*Severe dry mouth

While everyone experiences dry mouth from time to time, if it persists for weeks at a time, it can be a symptom of thyroid disease or other underlying health problems. Consult your healthcare provider if you notice that you have persistent dry mouth.


In addition to getting the right treatment for your thyroid disease (one way to manage your condition and its side effects), there are other ways to relieve dry mouth. Try some of these simple strategies:

  • Avoid foods that make dry mouth worse, such as salty foods and dry meat.
  • Avoid tobacco, alcohol, carbonated drinks, fruit juices, and caffeine, all of which can dry your mouth.
  • Drink plenty of water to keep your mouth moist.
  • Eat sugar-free saliva stimulants, such as sour gum and candy.
  • Run a humidifier in your bedroom overnight to keep the air moist.
  • Get regular preventive dental care (special toothpaste and fluoride may also be recommended).
  • Use a saliva substitute, such as SalivaMAX.
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Foods to Avoid When You Have Dry Mouth


If you have thyroid disease, you may also have dry mouth. If you’re still learning about your thyroid problem, you may not have time to make a connection. But the link exists because thyroid disease also means that the salivary glands produce and release less saliva. Low saliva can lead to dry mouth. Certain thyroid disease treatments can also cause dry mouth. A few quick and easy remedies can make living with dry mouth more bearable.

VigorTip words

Although dry mouth is an unpleasant effect of thyroid disease, it usually improves with treatment for hyperthyroidism or hypothyroidism. If your thyroid condition is adequately treated and there are persistent problems, some lifestyle changes and over-the-counter medications can relieve your dry mouth.