LDL Cholesterol: Normal Range, High & Low Causes
What LDL cholesterol measures
LDL carries cholesterol to your tissues. When there is too much, it can build up in artery walls. LDL is the main target when cholesterol is treated.
LDL cholesterol reference ranges
| Category | Conventional units | SI units |
|---|---|---|
| Optimal | Below 100 mg/dL | Below 2.6 mmol/L |
| Near optimal | 100 – 129 mg/dL | 2.6 – 3.3 mmol/L |
| Borderline high | 130 – 159 mg/dL | 3.4 – 4.1 mmol/L |
| High | 160 – 189 mg/dL | 4.1 – 4.8 mmol/L |
| Very high | 190 mg/dL or above | 4.9 mmol/L or above |
People with heart disease, diabetes or other high-risk conditions are often given a lower target. Your clinician sets the goal that fits your risk.
Need to convert units? Use the mg/dL ↔ mmol/L converter.
Common causes of a high result
- Diet rich in saturated and trans fat
- Inherited high cholesterol, especially when LDL is 190 or more
- Underactive thyroid
- Nephrotic syndrome or kidney disease
- Obesity and low physical activity
Common causes of a low result
- Cholesterol-lowering medicines
- Overactive thyroid
- Malnutrition or malabsorption
- Rare inherited conditions
How to prepare for the test
Fasting is often not required, but some labs calculate LDL from other values and ask for 9–12 hours of fasting. Follow your lab instructions.
How often to retest
About 4 to 12 weeks after starting or changing treatment, then as advised, often yearly once stable.
Track LDL cholesterol over time
Upload your reports and Labgist plots every LDL cholesterol result on one timeline, converts units and shows what changed.
Get the appFrequently asked questions
What is a normal LDL level?
Below 100 mg/dL (2.6 mmol/L) is optimal for most adults. Higher-risk people may be advised to aim lower.
Is calculated LDL accurate?
Calculated LDL is a good estimate for most people, but it becomes less reliable when triglycerides are very high. A direct LDL test can be used in that case.
How can LDL be lowered?
Diet changes, exercise, weight loss and, when needed, prescribed medicines such as statins. Talk with your clinician about what suits you.
Related tests
Sources
This page is general education and was last updated 2026-10-30. It is not a substitute for medical advice. See our editorial approach.