What Is LDL Cholesterol?

LDL cholesterol plays an important role in your body’s function. But LDL is called the “bad” cholesterol because too much of it can raise certain health risks.

A healthcare provider draws blood from a person's arm

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Low-density lipoprotein, or LDL, is a combination of fat and protein that carries cholesterol through the body. Cholesterol is a fatty-like substance that circulates in the blood and is needed to help you function.

LDL cholesterol makes up most of the body's cholesterol. However, when levels get too high, you can have an increased risk of heart disease and stroke. That’s why LDL cholesterol is often called “bad” cholesterol.

When LDL cholesterol gets too high, there are medications and lifestyle changes you can make to lower the levels. 

Is LDL Cholesterol Bad?

You need LDL cholesterol to function. Cholesterol is needed to build cells and make vitamins and other hormones. LDL helps that happen. So at regular amounts, LDL cholesterol is not bad.

LDL cholesterol is only considered bad if there is too much of it in your blood. When LDL levels are too high, the LDL can add up on the walls of blood vessels, creating plaque (fatty build-up) on the walls of the arteries. Too much plaque can lead to health problems, including stroke, heart attack, and peripheral artery disease.

Editor’s Note: LDL is just one of the lipoproteins that make up your total cholesterol number. The other main lipoprotein that affects your cholesterol is high-density lipoprotein (HDL). This is considered “good” cholesterol because it helps remove other forms of cholesterol. High levels of HDL can lower your risk for heart disease and stroke.

How Is LDL Cholesterol Measured?

LDL cholesterol is measured as part of a blood test called a lipid panel. A lipid panel will measure not only your LDL, but also your HDL and triglycerides (a type of fat in the blood).

Before your lipid panel, you should fast for nine to 12 hours. To get a blood sample, a healthcare provider will draw a small amount of blood from your arm. A laboratory will then measure your cholesterol levels using that blood sample. The cholesterol is measured in milligrams per deciliter (mg/dL).

Editor’s Note: Generally, people aged 45 to 65 should get a cholesterol screening every one to two years.  Children and younger adults should be screened every five years, while those older than 65 should be screened yearly.

You might need more frequent testing based on any family history or risk factors you may have for high cholesterol or cardiovascular disease.

LDL Cholesterol Levels

Based on your lipid panel results, your LDL cholesterol level will fall into one of five categories. Here are those categories and their corresponding LDL levels, for most adults:

LDL Cholesterol Category LDL Cholesterol Level
Good Less than 100mg/dL
Near Optimal 100-129mg/dL
Borderline High 130-159mg/dL
High 160mg/DL-189mg/dL
Very High 190mg/dL or above

These levels and corresponding categories might be different for special populations. For instance, if you have a history or high risk of atherosclerotic cardiovascular disease, your LDL target might be below 70mg/dL.

Children also have slightly different LDL categories. Here is what a child's LDL level could mean:

LDL Cholesterol Category LDL Cholesterol Level
Acceptable Less than 110mg/dL
Borderline  110–129mg/dL 
Abnormal  130mg/dL or above

Low LDL Cholesterol

If your LDL cholesterol is below 50mg/dL, your healthcare provider might consider you to have low LDL cholesterol. Low LDL cholesterol can happen for several reasons, including if you:

  • Have certain genetic conditions 
  • Take medication to lower high cholesterol
  • Have carcinoma of the colon or prostate
  • Have a blood disorder like anemia
  • Are hospitalized
  • Have an infection like tuberculosis, hepatitis C, or HIV

When the underlying condition is treated—or medication adjusted—LDL levels typically go back to more normal levels.

It is unclear what effect, if any, low LDL has on people. 

High LDL Cholesterol

If your healthcare provider determines that your LDL cholesterol is above an acceptable range, they may order another lipid panel or make sure that you followed your fasting guidelines for your initial test.

When your LDL cholesterol is high, it means you have too much LDL in your blood. This extra LDL can lead to atherosclerosis, the build-up of plaque in the arteries, which can cause health problems like stroke and heart disease.

For instance, when plaque builds up in your heart’s arteries, you can develop coronary artery disease (CAD). With CAD, the arteries will become hardened and narrowed, leading to sluggish or blocked blood flow to the heart. Because blood flow carries oxygen to the heart, a person with CAD will not get enough oxygen. The reduced flood flow could lead to chest pain. A person could also experience a heart attack if there is a complete blockage.

Editor’s Note: High LDL is not the only thing that determines your CAD risk. Factors like age and lifestyle habits can also dictate CAD risk.

How to Lower LDL Cholesterol

Based on your lipid panel results, personal health history, and family health history, your provider may recommend some type of intervention, such as lifestyle changes or medication, to lower your LDL levels.

Modify Your Diet

What you eat can affect LDL levels. You may want to begin eating more foods that can lower LDL cholesterol. This can include:

You may also want to avoid foods that have been shown to increase LDL levels, such as unfiltered coffee and foods with trans fats.

Following specific diets might also help you in modifying what you eat. The DASH diet—which stands for Dietary Approaches to Stop Hypertension—can not only lower blood pressure, but also LDL cholesterol. DASH includes lots of fruits, vegetables, whole grains, low-fat dairy, and lean meats. It limits sugars and fat.

The Therapeutic Lifestyle Changes diet might also help lower LDL. This diet encourages you to eat healthy fats, soluble fiber, fruits, vegetables, and fish high in omega-3 fatty acids while limiting salt, alcohol, and foods with cholesterol.

Get More Physical Activity

Research has shown that aerobic exercises—specifically, running, jogging, swimming, and cycling—can lower LDL levels and reduce the risk for heart disease.

Even low-impact activity can offer moderate reductions in LDL. Try walking, gardening, and stair climbing to lower LDL levels. The American Heart Association recommends at least 150 minutes of moderate-intensity exercise per week to help lower your LDL cholesterol levels.

Quit Smoking

Cigarette smoking has been linked to higher cholesterol levels. Research shows LDL levels can go down quickly after you quit. LDL levels continue to go down for each month you don't smoke. After 90 days, the LDL-lowering effects can be pretty significant.

Start Medication

There are different prescription medicines used to lower LDL levels. 

The first medication healthcare providers usually prescribe to lower your LDL is a statin. Statins include Lipitor (atorvastatin), Crestor (rosuvastatin calcium), and Zocor (simvastatin). They work by slowing down the liver's production of cholesterol. They might also lower triglycerides and mildly raise HDL. Research also shows that statins can lower the chance of a cardiovascular event, such as a heart attack or stroke.

Other medications that can help lower LDL include:

  • Bile acid sequestrants: These drugs work inside the intestines to retain bile from the liver and keep it from being absorbed into the bloodstream.The more liver bile there is, the more there is to bring down cholesterol. 
  • Niacin: This type of B vitamin improves all lipoprotein levels. It lowers total cholesterol, LDL cholesterol, and triglyceride levels and raises HDL levels. 
  • Injectable medicines: Drugs called PCSK9 inhibitors work to lower LDL cholesterol circulating in the bloodstream. They are typically prescribed to people with familial hypercholesterolemia—an inherited disease that causes high LDL levels—and people with atherosclerotic cardiovascular disease.

A Quick Review 

Low-density lipoprotein, or LDL, carries cholesterol throughout the body. Humans need cholesterol to build cells and make vitamins and other hormones. So LDL plays an important role. But when there is too much LDL cholesterol in the blood, plaque can build up on the walls of blood vessels. This build-up can raise your risk for cardiovascular events, such as a heart attack or stroke. Your LDL is measured through a blood test known as a lipid panel. For most adults, LDL levels less than 100mg/dL is considered good. If your LDL is too high, you can lower it with medication and lifestyle changes, including diet and exercise.

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  1. Centers for Disease Control and Prevention. LDL and HDL cholesterol and triglycerides.

  2. MedlinePlus. LDL: The "bad" cholesterol.

  3. American Heart Association. What is cholesterol?

  4. American Heart Association. What your cholesterol levels mean

  5. The National Heart, Lung, and Blood Institute (NHLBI). Blood cholesterol diagnosis.

  6. Grundy SM, Stone NJ, Bailey AL, et al. 2018 AHA/ACC/AACVPR/AAPA/ABC/ACPM/ADA/AGS/APhA/ASPC/NLA/PCNA guideline on the management of blood cholesterol: A report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Circulation. 2019;139(25). doi:10.1161/cir.0000000000000625

  7. Rosenson RS, Durrington, P. Low LDL-cholesterol: Etiologies and approach to evaluation. In: Freeman MW, Parikh N, eds. UpToDate. UpToDate; 2023.

  8. Olsson AG, Angelin B , Assmann G, et al. Can LDL cholesterol be too low? Possible risks of extremely low levels. J Intern Med. 2017;281(6):534-553. doi:10.1111/joim.12614

  9. Schoeneck M, Iggman D. The effects of foods on LDL cholesterol levels: A systematic review of the accumulated evidence from systematic reviews and meta-analyses of randomized controlled trials. Nutr Metab Cardiovasc Dis. 2021;31(5):1325-1338. doi:10.1016/j.numecd.2020.12.032

  10. National Heart, Lung and Blood Institute. The science behind the DASH eating plan.

  11. MedlinePlus. DASH eating plan.

  12. MedlinePlus. How to lower cholesterol with diet.

  13. Koh Y, Park J, Carter R. Oxidized low-density lipoprotein and cell adhesion molecules following exercise trainingInt J Sports Med. 2018;39(2):83-88. doi:10.1055/s-0043-118848

  14. American Heart Association. Prevention and treatment of high cholesterol (hyperlipidemia).

  15. Zhou MS, Chadipiralla K, Mendez AJ, et al. Nicotine potentiates proatherogenic effects of oxLDL by stimulating and upregulating macrophage CD36 signaling. Am J Physiol Heart Circ Physiol. 2013;305(4):H563-74. doi:10.1152/ajpheart.00042.2013

  16. Zhang Y, Chen L, Feng C, et al. ASSA 14-13-01 cigarette smoking-induced LDL dysfunction is partially reversible after smoking cessationHeart. 2015;101:A40–A41. doi:10.1136/heartjnl-2014-307109.107

  17. Centers for Disease Control and Prevention. Cholesterol-lowering medicines.

  18. Ziaeian B, Fonarow GC. Statins and the prevention of heart diseaseJAMA Cardiol. 2017;2(4):464. doi:10.1001/jamacardio.2016.4320

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