HDL Particle Number
Also known as: HDL-P
What Does HDL Particle Number Measure?
HDL Particle Number (HDL-P) measures the total count of high-density lipoprotein particles circulating in your blood, expressed as nanomoles per liter (nmol/L). Unlike standard HDL cholesterol (HDL-C), which measures only the amount of cholesterol carried inside HDL particles, HDL-P counts the actual number of particles themselves. This distinction is important because two people can have the same HDL cholesterol level yet have very different numbers of HDL particles, leading to significantly different cardiovascular risk profiles.
Why Does HDL Particle Number Matter?
HDL particles play a critical role in reverse cholesterol transport, a process where excess cholesterol is removed from artery walls and transported back to the liver for processing and elimination. A higher number of HDL particles generally means more efficient cholesterol removal and better cardiovascular protection. Research, including the MESA and Framingham Heart Studies, has shown that HDL-P is a stronger predictor of cardiovascular disease risk than standard HDL cholesterol alone. Individuals with low HDL-P—even if their HDL-C appears normal—may have a significantly elevated risk of heart attack and atherosclerosis, making this a more sensitive marker for identifying hidden cardiovascular risk.
Normal Ranges
Males
Greater than 30.5 µmol/L (optimal); 25.0–30.5 µmol/L (borderline); Less than 25.0 µmol/L (high risk)
Females
Greater than 33.0 µmol/L (optimal); 28.0–33.0 µmol/L (borderline); Less than 28.0 µmol/L (high risk)
Children
Varies by age; typically assessed in adolescents with cardiovascular risk factors; reference ranges not well-standardized for pediatric populations
Causes of High Levels
- Regular aerobic exercise, which stimulates hepatic production of HDL particles
- Moderate alcohol consumption (though this is not recommended as a health strategy)
- Use of niacin (vitamin B3) therapy, which increases HDL particle production
- High dietary intake of healthy fats such as omega-3 fatty acids and monounsaturated fats
- Genetic variants such as cholesteryl ester transfer protein (CETP) deficiency, which dramatically elevates HDL-P
- Fibrate medications (e.g., fenofibrate), which are known to raise HDL particle counts
Causes of Low Levels
- Insulin resistance and type 2 diabetes, which impair HDL particle maturation and accelerate catabolism
- Metabolic syndrome, characterized by central obesity, high triglycerides, and low HDL
How to Improve Your HDL Particle Number
Diet
- Increase intake of omega-3 fatty acids from fatty fish (salmon, mackerel, sardines) at least 2–3 times per week to boost HDL particle production
- Replace refined carbohydrates and added sugars with whole foods to reduce triglycerides and improve HDL-P
- Consume monounsaturated fats from sources like olive oil, avocado, and almonds, which are associated with higher HDL particle counts
- Increase dietary fiber intake through vegetables, legumes, and oats to support lipid metabolism
- Limit trans fats and highly processed foods, which are known to lower HDL-P and promote inflammation
Supplements
- Niacin (vitamin B3): 500–2000 mg/day (extended-release form preferred) under medical supervision—one of the most effective agents for raising HDL-P
- Omega-3 fish oil: 2–4 g/day of combined EPA and DHA to reduce triglycerides and support HDL particle remodeling
- Phosphatidylcholine: 1–3 g/day may support HDL particle formation and reverse cholesterol transport
- Berberine: 500 mg twice daily has shown modest improvements in lipid profiles including HDL metrics
- Pantethine (vitamin B5 derivative): 600–900 mg/day may help improve HDL levels in some individuals
Related Biomarkers
Frequently Asked Questions
What is the difference between HDL-P and regular HDL cholesterol?
HDL cholesterol (HDL-C) measures the total amount of cholesterol carried within HDL particles, while HDL-P counts the actual number of HDL particles in your blood. Think of it like trucks on a highway: HDL-C tells you how much cargo is being carried, while HDL-P tells you how many trucks there are. You could have a few large, heavily loaded trucks (high HDL-C, low HDL-P) or many smaller trucks (higher HDL-P). Research shows that having more particles—regardless of how much cholesterol each carries—is more strongly associated with cardiovascular protection.
Can I have a normal HDL cholesterol level but still have a dangerously low HDL-P?
Yes, this is called the HDL discordance phenomenon and it is clinically significant. Some individuals have normal or even high HDL cholesterol levels but relatively few, large HDL particles. This pattern is often seen in people with insulin resistance or metabolic syndrome. Studies have found that in cases of discordance, HDL-P is a better predictor of cardiovascular risk than HDL-C. This is one of the main reasons advanced lipid testing that includes particle number is recommended for people at intermediate cardiovascular risk.
How is HDL Particle Number measured?
HDL-P is most commonly measured using Nuclear Magnetic Resonance (NMR) spectroscopy, a technology that analyzes the physical properties of lipoprotein particles in a blood sample. This test is typically performed through specialized labs such as LabCorp (NMR LipoProfile) or Boston Heart Diagnostics. It requires a standard blood draw, usually after fasting for 9–12 hours. Ion mobility analysis is another method used by some labs. These tests are more expensive than standard lipid panels and may not always be covered by insurance, but they provide significantly more cardiovascular risk information.