HDL

HDL (high density lipoprotein) is a substance used to transport cholesterol in the blood. Known as the "good cholesterol," HDL picks up excess cholesterol dropped off by low density lipoproteins and transports it to your liver. The higher your HDL cholesterol level, the better off you are. Lifestyle changes that can raise it include losing weight, exercising, and quitting smoking. Certain medications can also help.

 

An Introduction to HDL

High density lipoprotein, or HDL for short, is a substance found within the body that is used to transport cholesterol. HDL is also referred to as HDL cholesterol or "good cholesterol."
 

Understanding Cholesterol and Lipoproteins

In order to better understand HDL, it may be helpful to understand a little more about cholesterol and lipoproteins.
 
 
Cholesterol is a soft and waxy substance found in all of your body's cells. Your body needs this cholesterol in order to work properly. However, in order to get to all of your cells, cholesterol needs to travel through the bloodstream. But because cholesterol is a fat, it separates from the blood similar to the way that oil separates from water.
 
To keep this from happening, proteins form a shell around the cholesterol, making a "cholesterol complex." It is then released into the bloodstream and travels to where it needs to go.
 
A protein that is linked to cholesterol to form this cholesterol complex is called a "lipoprotein." There are several different types of lipoproteins. When talking about cholesterol, though, we normally talk about two types. One is good and the other can be bad. You have probably heard about "good cholesterol" and "bad cholesterol." What is interesting is that for both good cholesterol (HDL) and bad cholesterol (LDL), the cholesterol is the same; what makes it good or bad is the type of lipoprotein that it is inside.
 

HDL: The "Good Cholesterol"

The good lipoprotein, which is also the "good cholesterol," is called HDL. HDL cholesterol is "good cholesterol" because it picks up the extra cholesterol that was dropped off by the LDLs and brings it to your liver. This way, your liver can repackage it to use it later or simply get rid of it. Because HDL cholesterol removes excess bad cholesterol (LDL), it is good to have high levels of HDL in your system and low levels of LDL. Think of "H" for "high" to help you remember this about HDL. And "L" stands for low, which is a way to remember that you want low levels of LDL.
 

HDL: The Numbers

Because HDL helps remove cholesterol from the blood, it can help keep cholesterol from building up in the walls of the arteries (known as plaque). Plaque buildup can lead to a condition called atherosclerosis, which is narrowing of the arteries. Narrowing of the arteries can lead to heart disease.
 
(Click Cholesterol and Heart Disease for more information.)
 
This explains why if your HDL cholesterol level is low (below 40 mg/dL), you are at substantially higher risk for heart disease. The higher your HDL cholesterol level, the better off you are.
 
HDL Cholesterol Level
HDL Cholesterol Category
Less than 40 mg/dL
A major risk factor for heart disease
40–59 mg/dL
The higher, the better
60 mg/dL and above
Considered protective against heart disease

 

(Cholesterol levels are measured in milligrams [mg] of cholesterol per deciliter [dL] of blood.)
 
The average HDL cholesterol level for men is about 45 mg/dL; for women, it is about 55 mg/dL.
 

Raising HDL

There are several ways for people with low HDL to raise it. Lifestyle changes that are known to increase HDL include:
 
  • Losing weight
  • Quitting smoking
  • Moderate exercise
  • Moderate alcohol use, especially red wine.
     
Certain medications can also raise HDL levels, including:
 
  • Cholesterol medications (such as statins, fibrates, and nicotinic acid)
  • Estrogen.
     
(Click Raising HDL for more information on how to increase HDL cholesterol or click Cholesterol Medications for more information on these cholesterol-lowering drugs.)
 
Written by/reviewed by: Arthur Schoenstadt, MD
Last reviewed by: Arthur Schoenstadt, MD