The Link Between Thyroid Disease and Cholesterol


Thyroid disease and cholesterol levels are closely related.

  • High cholesterol (hyperlipidemia) is linked to hypothyroidism (underactive thyroid).
  • A sudden drop in cholesterol can be a warning sign of hyperthyroidism (overactive thyroid).
  • Treating thyroid disease can correct cholesterol levels.
  • Cholesterol drugs can affect thyroid disease and its treatments.

This article talks more about why thyroid disease and high cholesterol are linked, the problems that can cause, and how to manage both conditions at once.

Why Thyroid and Cholesterol Are Linked

Thyroid hormones have several jobs. One is controlling how your body uses cholesterol and other lipids (fats). Another is helping your liver produce fatty acids, which store energy for you to use later.

When thyroid hormones are out of whack, it affects all these processes. Getting them in balance helps things work right again.


Low Thyroid & High Cholesterol

One measurement of thyroid function is a hormone called thyroid-stimulating hormone (TSH). Made by a small gland at the base of the brain called the pituitary, TSH tells your thyroid how hard to work.

High TSH levels mean you have an underactive thyroid. Symptoms include:

  • Fatigue
  • Weight gain
  • Slow heart rate

Studies show that people with high TSH levels have much higher total cholesterol and LDL (bad cholesterol) levels than people with normal thyroid tests.

Health Risks

Untreated hypothyroidism is linked to serious health risks. These include:

Any of these can be fatal.

High cholesterol raises heart disease and stroke risk even more.

High Thyroid & Low Cholesterol

While it’s usually good, sometimes low cholesterol is a bad sign. A sudden drop can be a sign of an overactive thyroid.

In hyperthyroidism, your thyroid produces too much T3 and T4. High levels of these hormones speed up processes in your body, leading to:

  • Anxiety
  • Sudden weight loss
  • Rapid heartbeat

Interestingly, while hyperthyroidism is linked to low cholesterol, high cholesterol may be linked to a hyperthyroidism-related complication.

Graves’ disease is an autoimmune condition that causes hyperthyroidism. It sometimes involves an eye disease called orbitopathy. Increased levels of LDL and total cholesterol are risk factors for orbitopathy.

Health Risks

Without treatment, hyperthyroidism can lead to:

Low cholesterol is associated with an increased risk of:

  • Some cancers
  • Mood disorders
  • Heart disease

Both conditions are associated with heart disease, possibly compounding the risk.


Low thyroid activity is linked to high total and LDL cholesterol. Without treatment, an underactive thyroid could lead to heart disease, stroke, and other concerns.

High thyroid activity is linked to low cholesterol. Untreated, an overactive thyroid can lead to brittle bones, abnormal heart rhythm, and more.

Thyroid Treatment and Cholesterol

Treatment approaches for underactive and overactive thyroid differ. Adequate thyroid treatment cannot only help manage your thyroid, but impact your cholesterol as well.

Underactive Thyroid Treatment

Hypothyroidism is usually treated with the drug Synthroid (levothyroxine), a synthetic form of the hormone T4. Often, taking this drug is all it takes to improve thyroid levels and, subsequently, cholesterol levels.

In fact, experts say if you’re diagnosed with high cholesterol, you should be checked for thyroid disease before being given cholesterol-lowering drugs because levothyroxine may be a better treatment.

A large study of people with hypothyroidism and high cholesterol showed that treating the thyroid problem corrected cholesterol levels 60% of the time.

A 2017 study noted it even helps in people who have borderline hypothyroidism and cholesterol problems.

Since levothyroxine doesn’t always get cholesterol levels in range, additional medical treatments may be needed. These include cholesterol-lowering medications such as:

  • Statins, such as Lipitor (atorvastatin) or Crestor (rosuvastatin)
  • Zetia (ezetimibe)
  • PCSK9 inhibitors, such as Repatha (evolocumab) and Praluent (alirocumab)

Overactive Thyroid Treatment

Treating hyperthyroidism can help raise too-low cholesterol levels.

Possible treatments include:

  • Antithyroid drugs: Medications that lower your thyroid’s hormone production
  • Radioiodine therapy: Comes in capsule or liquid form; slowly destroys thyroid cells that produce hormones
  • Surgery: All or part of the thyroid is removed

If your entire thyroid gland is removed, you’ll need to take thyroid replacement hormone (such as levothyroxine) for the rest of your life. This is sometimes the case with partial removal and radioiodine therapy as well.


Treatment with levothyroxine can improve both an underactive thyroid and high cholesterol.

An overactive thyroid and low cholesterol can both be improved with medication, radioiodine therapy, or surgery directed at stunting the overproduction of thyroid hormone.

Cholesterol Treatments and Thyroid Disease

Cholesterol treatments can affect thyroid disease and treatment in several ways.


Drugs classified as bile acid resins may prevent your body from absorbing levothyroxine. They’re prescribed for hyperthyroidism and include:

You should take these drugs at least four hours after taking levothyroxine to sidestep this concern.

Muscle Pain

Muscle pain is a common side effect of statins, such as:

If you have hypothyroidism, you’re especially likely to have this side effect.

Hyperthyroidism Symptoms

Niacin is one treatment for increasing HDL (“good cholesterol”) levels.

Its side effects, such as flushing, can closely mimic the symptoms of hyperthyroidism. That might make you think your thyroid treatments aren’t working properly.

Thyroid Eye Disease

On the plus side, a 2018 study found that treating high cholesterol with statin medications reduced the risk of Grave’s orbitopathy.


Drugs used to lower cholesterol can produce side effects that mimic symptoms of thyroid disease and interfere with thyroid medication absorption. Those with thyroid disease may also be more likely to experience side effects of cholesterol drugs than others.

Lifestyle Changes for Both Conditions

Lifestyle changes can help you manage cholesterol and thyroid problems. Your healthcare provider may recommend the following:

  • Diet: An anti-inflammatory diet may lower inflammation from autoimmune thyroid disease and lower cholesterol.
  • Weight loss: Even small weight reductions can lower LDL cholesterol levels and improve thyroid health.
  • Exercise: Regular exercise can improve energy levels in hypothyroidism, and may raise good cholesterol levels.
  • Quitting smoking: Smoking harms the thyroid and increases the risk of complications. It also adds to the cholesterol-related risk of heart disease and stroke.


Thyroid hormones and cholesterol levels are connected. If your cholesterol is high or drops suddenly, get your thyroid checked.

Thyroid treatments cannot only help you reduce your risk of complications such as heart attack and stroke, but they can also help you manage cholesterol.

If you are on cholesterol drugs, know that they can affect your thyroid disease and treatments.

A Word From Get Meds Info

You don’t necessarily have to have your thyroid condition managed by an endocrinologist—a healthcare provider who specializes in treating hormone issues. Many healthcare providers feel confident managing these conditions themselves.

However, if you have other health issues or your healthcare provider is not comfortable treating you, seeing a specialist may be best.

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