Both thyroid and blood sugar issues involve a complex interplay of hormones in the body. If you have a condition like hypothyroidism, it can make managing your blood sugar levels more difficult.

The thyroid is a butterfly-shaped gland located in the neck. It produces hormones that are essential to growth, development, and metabolism. For this reason, impaired thyroid function may impact a person’s blood sugar levels and is closely linked to type 1 and type 2 diabetes.

Hypothyroidism is the term doctors use for low thyroid function. Hypoglycemia is the term doctors use for low blood sugar.

Keep reading to learn how these two conditions are linked, as well as how other related conditions and medications may affect your blood sugar.

While hypothyroidism does not directly lower a person’s blood sugar, it may contribute to low blood sugar episodes.

This is because the thyroid gland produces hormones that affect metabolism, which is how the body converts food into energy. With hypothyroidism, a person’s metabolism decreases. When this process slows down, excess insulin hormone circulating in your body may cause blood sugar levels to drop and result in symptoms of hypoglycemia.

Hypoglycemia in people without diabetes is rare. But when it’s related to hypothyroidism, low blood sugars may result from:

A person with both diabetes and hypothyroidism may experience even more challenges.

As a result, people on diabetes medications who also have hypothyroidism may experience hypoglycemia from the slow metabolism of these glucose-lowering drugs.

What is hypoglycemia?

Hypoglycemia affects different people in different ways. If you experience low blood sugar, you may find it helpful to write down the symptoms you experience so you can spot an episode before it becomes severe.

Mild symptoms:

  • dizziness
  • rapid heart rate
  • anxiety or nervousness
  • sweating
  • shakiness
  • irritability
  • hunger
  • nausea
  • weakness or sleepiness

More severe symptoms:

  • headaches
  • confusion
  • vision issues
  • coordination issues
  • seizures
  • coma
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It’s important to note that the reverse is also true. Having diabetes may increase a person’s chances of developing thyroid disease — either hyperthyroidism or hypothyroidism.

Hashimoto’s thyroiditis is an autoimmune thyroid condition in which the immune system attacks the thyroid gland. This condition is the most common cause of hypothyroidism in the United States.

Researchers share that glucose intolerance affects up to 50% of people with autoimmune-related thyroid issues like Hashimoto’s. This condition can lead to issues with low blood sugar as well.

In one study, researchers explain that autoimmune-induced hypothyroidism leads to hypoglycemia by decreasing the body’s insulin requirement and increasing insulin sensitivity. When the body is more sensitive to insulin, blood sugar levels can drop too low and cause symptoms.

On the other end of the spectrum, hyperthyroidism is a condition where the body produces too much thyroid hormone. This may lead to symptoms like increased appetite, weight loss, reduced cholesterol, and insulin resistance.

Having hyperthyroidism increases a person’s chances of developing hyperglycemia (high blood sugar). This situation may also increase a person’s chances of developing diabetes or make existing diabetes more difficult to manage.

Levothyroxine is a drug used to treat hypothyroidism and thyroid cancer. It’s a synthetic form of the thyroid hormone thyroxine or T4, and it’s a generic drug for the brand name medication, Synthroid.

This medication may actually raise blood sugar levels and is used to treat severe hypothyroidism or myxedema coma.

That said, older research suggests that levothyroxine may lead to hypoglycemia in people with existing liver issues. Depending on your health history, your doctor may want to monitor your blood sugar while taking this drug.

Also, speak with your doctor if you take diabetes medications, whether they’re oral drugs or insulin. Levothyroxine may change how these medications work, and your doctor may need to adjust your dosages.

Hypothyroidism and hypoglycemia are related health conditions that impact the endocrine system. Research has shown a link between thyroid conditions and blood sugar levels, including diabetes. Likewise, people with diabetes may be more likely to have coexisting thyroid issues.

If you’re experiencing symptoms that concern you, make an appointment with your doctor. You may be referred to an endocrinologist (a specialist who treats conditions of the endocrine system) who can diagnose thyroid disorders and blood sugar issues using blood tests.

Appropriate treatment can help stabilize your thyroid function and blood sugar levels, allowing you to feel your best again.