High cholesterol is common with hypothyroidism. Statins often help lower cholesterol levels, but hypothyroidism can sometimes lead to statin intolerance.

Your thyroid gland is located at the front of your neck near your collarbone. It consists of two lobes on either side of your trachea that give it a “butterfly” shape.

Although it’s small, your thyroid gland has big responsibilities. It produces hormones essential for body-wide processes related to metabolism, cognition, development, and energy production.

When your thyroid gland doesn’t produce enough thyroid hormones to support your body’s needs, it’s known as hypothyroidism. Hypothyroidism can contribute to a variety of medical symptoms and conditions, including high cholesterol, which is often treated with medications called statins. However, hypothyroidism may also increase your risk of statin intolerance.

Statin intolerance, characterized by a range of symptoms that prevent you from taking statin medications at recommended dosages, affects approximately 5% to 30% of people prescribed statins.

Hypothyroidism can increase your chance of experiencing statin intolerance by as much as 30%. This happens as a result of how statins and hypothyroidism individually affect your body’s muscle function and ability to metabolize lipid (fat) as well as any medications you may take.

Research from 2019 notes that anyone with hypothyroidism has an increased risk of statin intolerance, even if hypothyroidism is being effectively managed.

However, research from 2018 found that the greatest risk is for people with mismanaged hypothyroidism. When hypothyroidism is well-managed, thyroid hormone replacement therapy helps restore many of the processes affected by the condition, reducing the chance they may contribute to statin intolerance.

The reasons hypothyroidism can contribute to statin intolerance are complex and involve various factors, including your:

  • metabolism
  • liver function
  • cellular energy production

When hypothyroidism and statin effects overlap or interact, they can cause a variety of treatment challenges and side effects.

Hypothyroidism and higher statin doses

Hypothyroidism has a direct effect on your cholesterol levels. It reduces the expression of low-density lipoprotein (LDL) receptors in your liver, which lowers the amount of LDL pulled from your bloodstream.

Elevated amounts of LDL circulating in your blood can mean it takes higher doses of statin medications to help you reach your target cholesterol goals. The higher your statin dose, the higher your chance of statin intolerance.

Hypothyroidism and mitochondria dysfunction

Mitochondria are components within your cells that generate the majority of cellular energy in the form of adenosine triphosphate (ATP). Your muscle cells are heavily populated with mitochondria because they require constant energy for function and repair.

Hypothyroidism can cause dysfunction of your mitochondria, reducing how well they produce energy. Statins can also impair mitochondria activity by reducing coenzyme Q10, an important antioxidant that supports the production of ATP.

Having mismanaged hypothyroidism while taking a statin can compound the negative effects on mitochondria, increasing the chance of muscle pain, weakness, and myopathy. In rare cases, it can lead to rhabdomyosis, a potentially life threatening breakdown of skeletal muscle tissue.

Muscle symptoms are the most common symptoms in statin intolerance, reported by approximately 60% of adults.

Reduced statin clearance

Your liver metabolizes medications like statins, but hypothyroidism can slow that metabolism down. This means your liver is less capable of clearing statins from your bloodstream, which keeps their levels elevated and increases the risk of toxicity.

Since hypothyroidism directly affects your liver’s ability to pull cholesterol from the bloodstream, high cholesterol commonly occurs alongside this condition.

Statins are a first-line treatment for high cholesterol (hypercholesterolemia). Receiving a hypothyroidism diagnosis doesn’t automatically mean you can’t take a statin medication. Your doctor will carefully consider your diagnoses along with other individual risk factors for statin intolerance, such as:

  • age 65 years and up
  • obesity
  • female biological sex
  • diabetes
  • alcohol use
  • race
  • use of calcium channel blockers or antiarrhythmic drugs

When you can’t take statins in hypothyroidism, other medications and therapeutic interventions might help lower your cholesterol levels.

Other medications that can help lower lipid levels in your bloodstream include:

  • adenosine triphosphate-citrate lyase (ACLY) inhibitors
  • bile acid sequestrants
  • ezetimibe
  • fibrates
  • nicotinic acid
  • omega-3s
  • PCSK9 inhibitors

These drugs help lower cholesterol through different mechanisms than statins, making them more tolerable for some people. It may take some trial and error to find a lipid-lowering medication that works for you and doesn’t negatively affect your hypothyroidism treatment.

In addition to lipid-lowering medications, your doctor will make recommendations for lifestyle changes that help lower cholesterol, including:

  • eating a heart-healthy diet that includes fiber-rich plant foods like fruits and vegetables, fish, and healthy fats
  • limiting alcohol intake
  • quitting smoking (for help, contact 1-800-QUIT-NOW)
  • exercising regularly
  • reaching and maintaining a moderate weight

Hypothyroidism can increase your risk of experiencing statin intolerance, a set of symptoms that prevent you from taking statin medications at their recommended effective dose — or at all.

Hypothyroidism has direct effects on cholesterol levels and can indirectly influence the risk for statin intolerance by affecting processes related to metabolism, liver function, and energy production.

If you’re unable to take statins with a hypothyroidism diagnosis, you can work with your doctor to discuss other lipid-lowering medications and make any necessary healthy lifestyle changes to help lower cholesterol.