Guide to High-Density Lipoprotein (HDL)

WRITTEN BY

The Levels Team

Updated: 05/22/2025|12 min read

Summary

High-density lipoprotein (HDL) is a complex particle that helps remove cholesterol from tissues and provides anti-inflammatory protection to blood vessels.

Why It Matters

HDL cholesterol is often called "good" cholesterol because one of its functions is to bind to and transport cholesterol from peripheral tissues through the bloodstream to the liver for processing and elimination.

This cleanup process helps prevent cholesterol buildup in your arteries, reducing your risk of heart disease and stroke.

In addition to scrubbing cholesterol from artery walls, HDL plays several other critical roles in maintaining cardiovascular health. It also reduces inflammation in blood vessels, provides antioxidant protection against LDL cholesterol, and carries important signaling molecules throughout the circulatory system.

In blood tests, HDL cholesterol measures the amount of cholesterol carried by these HDL particles, reported in milligrams per deciliter (mg/dL). This measurement serves as an indicator of how effectively your body can remove excess cholesterol from tissues.

Higher HDL levels (within range) are generally protective for heart health. However, it's not just about how much HDL you have but also how well it functions. 

Clinical Ranges

Female:

• <20 Years: >45 mg/dL
• ≥20 Years: ≥50 mg/dL

Male:

• <20 Years: >45 mg/dL
• ≥20 Years: ≥40 mg/dL

Lifestyle Choices That Can Impact It

Habits that help raise HDL levels:

• Regular aerobic exercise stimulates the production of HDL particles and enhances their ability to remove cholesterol.
• Mediterranean or natural, whole-food diets provide healthy fats and fiber that support HDL production and function.
• Adequate sleep supports proper hormone regulation that influences HDL metabolism.
• Weight management maintains a healthy metabolism and hormone balance for optimal HDL production.
• Stress reduction helps regulate hormones that affect HDL synthesis and function.

Habits that can lower HDL levels:

• Poor diet high in trans fats, saturated fats, refined carbs, ultra-processed foods, or added sugars interferes with HDL production and reduces its effectiveness.
• Smoking damages HDL particles and reduces their ability to remove cholesterol.
• Excessive alcohol use disrupts liver function and HDL synthesis.
• Chronic stress elevates cortisol which can suppress HDL production.
• Rapid weight changes disrupt metabolic processes that regulate HDL levels.
• Chronic inflammation from any source can impair HDL's protective functions.

Other Factors That Can Impact It

Medications

• Beta-blockers: can lower HDL
• Statins: may increase HDL
• Fibrates: increase HDL moderately
• Niacin: can significantly increase HDL
• Anabolic steroids: lower HDL
• Progestins: can lower HDL

Hormones

• Testosterone: endogenous testosterone is linked to higher HDL in men, but testosterone replacement therapy may lower HDL
• Thyroid hormones: affect HDL metabolism
• Growth hormone: can impact HDL levels
• Cortisol: may lower HDL
• Estrogen: increases HDL

Environment

• Levels can drop during the winter due to changes in diet, reduced physical activity, and less vitamin D absorption.
• Living at a higher altitude may increase levels. 

Testing Accuracy and Stability

Major Factors That Can Affect Results

• Recent exercise can raise levels.
• An illness or injury can lower HDL due to an increase in inflammation. A more severe illness will have a greater effect on your levels.
• Dehydration may lead to more concentrated cholesterol levels in your blood, and an inaccurately high reading.
• Significant weight gain can lower levels, while significant weight loss can raise levels.
• Chronic stress can lead to lower HDL levels.

How it Relates to Other Markers

Your provider may consider other tests in addition to your HDL to develop a more complete profile of your cholesterol. 

• LDL cholesterol: This cholesterol can increase the risk of heart disease. Higher levels usually mean higher risk, especially if HDL is low.
• Triglycerides: High triglycerides can lower HDL and increase the risk of heart disease.
• Total cholesterol: This test looks at all the cholesterol in your body, including HDL, LDL, and a portion of your triglycerides. HDL is typically lower when LDL is higher.
• Apolipoprotein A1: This is the main protein in HDL. It measures HDL function.
• C-reactive protein: It looks at inflammation, which can affect HDL function.
• Blood sugar markers: Blood sugar tests help screen for diabetes, which affects HDL metabolism.
• Thyroid function: Thyroid status influences HDL levels.
• Liver function tests: Liver health affects HDL production.

What Results May Mean in the Context of Other Markers

• High HDL with low triglycerides: Optimal pattern that can suggest good metabolic health.
• High HDL with high triglycerides: May indicate inflammation or metabolic dysfunction despite high HDL.
• Low HDL with high triglycerides: May indicate insulin resistance
• Low HDL with normal triglycerides: May indicate inflammation or early metabolic dysfunction.
• Very high HDL (>80): Not necessarily protective; may indicate dysfunctional HDL metabolism.

Follow-up Considerations

You should always speak to your doctor if you have medical questions or before making medical decisions.

When Re-Testing May Be Appropriate

• Low HDL: Testing every six weeks while implementing lifestyle changes
• Borderline low HDL: Quarterly monitoring to track improvement
• High HDL: Annual monitoring if other markers are normal

Additional Testing Your Doctor May Consider

• HDL particle number and size
• HDL functionality tests
• Advanced inflammatory markers
• Oxidized LDL
• Advanced lipoprotein testing (VAP)

When Additional Care May Be Warranted

• Low HDL: If levels don't improve after 3 months of lifestyle changes
• Borderline low HDL: If levels decrease or don't improve with lifestyle optimization
• High HDL: Generally only if accompanied by other abnormal lipid values or symptoms

Bibliography