Small Dense Low-Density Lipoprotein Subfraction 3

sdLDL-3 is a small, dense form of LDL cholesterol that poses a high risk for heart disease when present in high amounts.

📋 About This Biomarker

Small Dense LDL 3 (sdLDL-3) is one of the smallest and most dangerous types of LDL ("bad") cholesterol. LDL cholesterol helps transport fats around the body, but the size and density of the particles matter. The smaller and denser they are, the more likely they are to squeeze into artery walls, get oxidised (damaged), and trigger inflammation - a key step in the development of heart disease. sdLDL-3 is part of the group of particles known to be highly atherogenic, meaning they can significantly increase your risk of blocked arteries, heart attack, and stroke. These particles are especially common in people with insulin resistance, type 2 diabetes, metabolic syndrome, and diets high in processed carbohydrates. Understanding sdLDL-3 levels helps reveal cardiovascular risks that don’t show up in basic cholesterol tests. It’s like identifying the most problematic group in a crowd - they may be small, but they cause the most trouble.

🎯 Why We Test This

sdLDL-3 reveals hidden risks that standard cholesterol tests may miss. Even if your total LDL is normal, having high sdLDL-3 can increase your heart disease risk. This test is especially useful for people with diabetes, obesity, high triglycerides, or a family history of heart disease.

⚠️ What Affects It

High intake of sugar and refined carbs, low physical activity, excess body fat, and conditions like insulin resistance and type 2 diabetes can lead to increased sdLDL-3 levels. Other influences include smoking, stress, genetics, low HDL (“good”) cholesterol, and certain medications. Hormonal changes, such as during menopause, may also increase small dense LDL.

📈 How to Improve

To lower high or borderline sdLDL-3, focus on cutting sugar, refined carbs, and alcohol, and increase fibre, healthy fats (like omega-3s), and exercise - especially cardio and strength training. If sdLDL-3 is low or near the lower limit, that’s excellent - maintain your current healthy lifestyle to keep it that way. Regular check-ups will help monitor any changes.

📊 Understanding Your Results (mmol/L)

Low (< 0 mmol/L)
Low sdLDL-3 levels are generally very beneficial and indicate a low cardiovascular risk from this biomarker. It reflects a healthy lipid balance, often seen in people who eat a balanced diet, exercise regularly, and have good insulin sensitivity.
Optimal (0 - 0.2 mmol/L)
sdLDL-3 in the healthy range suggests your cholesterol is mostly being transported in larger, less harmful forms. This is a positive sign, as fewer small dense particles means a lower risk of arterial damage and heart disease.
High (> 0.2 mmol/L)
High sdLDL-3 means your blood contains a large number of small, dense, highly damaging LDL particles. This raises your risk of plaque build-up in your arteries and is a strong warning sign for cardiovascular disease - especially if accompanied by high triglycerides or low HDL. Urgent lifestyle and medical management may be needed.
Also known as: Small Dense LDL 3, sdLDL-3