LDL Cholesterol
Low-Density Lipoprotein
What this test measures
LDL is often called 'bad' cholesterol. It carries cholesterol to your arteries where it can build up and cause blockages. High LDL increases your risk of heart attacks and strokes.
Understanding the numbers
Typical range: Below 3 mmol/L
If you have heart disease or high risk, your doctor may want it below 2 mmol/L or even lower.
- Optimal: 0–2 mmol/L
- Near optimal: 2–3 mmol/L
- Borderline: 3–4 mmol/L
- High: 4–8 mmol/L
Key numbers
- 2.0 mmol/L — Secondary-prevention target (after heart attack/stroke)
- 3.0 mmol/L — General-population threshold
- 4.9 mmol/L — Simon Broome FH screening flag
- 5.0 mmol/L — Strongly suggests inherited cause
Targets are from NICE NG181 (lipid management). Secondary prevention aim: LDL-C below 2 mmol/L (or 40% reduction). The 4.9 mmol/L flag is from Simon Broome criteria used to screen for familial hypercholesterolaemia in UK primary care.
Ranges can vary slightly between laboratories — your report may show slightly different numbers. This page does not read or interpret your result; your GP looks at it alongside your history and other tests.
What a higher-than-normal result can mean
- Too much bad cholesterol is building up
- This can lead to blocked arteries over time
- You may need to eat less saturated fat
- Your GP may recommend statins if lifestyle changes are not enough
Questions you could ask your GP
- What is my target LDL level based on my personal risk factors?
- Which foods should I avoid to help lower my LDL?
- Would you recommend statins for me, and what are the side effects?
- Could my high LDL be inherited (familial hypercholesterolaemia)?
Example stories
These are made-up examples to show how results are talked about in real appointments. They are not real patients.
Statin started a year ago
Marcus started atorvastatin 20 mg after his QRISK came out at 18%. His LDL before was 4.3; a year later it was 1.8 — a 58% drop.
What the GP said: “That's an excellent response to the statin. You're well below target. Stay on the same dose and we'll recheck in a year.”
NICE asks for at least a 40% drop in LDL on statin therapy; Marcus achieved more. A low LDL on treatment is the treatment working — not something to be worried about.
Diabetes, cholesterol review
Hemal has Type 2 diabetes. His LDL was 2.7 mmol/L despite being on simvastatin 40 mg.
What the GP said: “In diabetes we aim for LDL below 2 mmol/L because your background risk is higher. Let's switch you from simvastatin to atorvastatin — it's stronger at lowering LDL.”
What happened next: Three months after the switch, Hemal's LDL was 1.7 mmol/L. No side effects.
'Normal' LDL targets are personalised. People with diabetes, established heart disease, or high QRISK aim lower. If you're not at your target on one statin, a stronger one often gets you there.
Raised on NHS health check
Jyoti's LDL was 3.6 mmol/L on a routine check. No other risk factors — non-smoker, normal BP, no diabetes. QRISK3 was 4%.
What the GP said: “Your LDL is slightly raised but your overall 10-year risk is low. Statins aren't needed. Diet and activity can help — and we'll recheck in a few years.”
What happened next: Jyoti cut back on fried snacks, added more oily fish and nuts, and started walking daily. Her LDL was 3.2 at the next check.
A borderline LDL on its own doesn't automatically mean treatment. Your GP is treating your overall risk, not just one number. Lifestyle changes alone can often move the needle enough at this level.
Father had heart attack at 44
Rohan's LDL was 5.4 mmol/L. His father had a heart attack at 44 and his cousin was on statins in her twenties.
What the GP said: “This pattern strongly suggests familial hypercholesterolaemia. I'm referring you to the lipid clinic for genetic testing. We'll start a statin now while that's arranged.”
What happened next: Genetic testing confirmed FH. Rohan's two children were screened and his daughter (age 8) was also positive — she'll be monitored and started on treatment in her teens.
An LDL above around 5 mmol/L, especially with early heart disease in the family, raises the possibility of inherited high cholesterol. Treatment works very well — and identifying it means your relatives can be checked too.
Before you act on anything here
This page is general information, written to help you understand — it is not personal medical advice and it cannot tell you what is right for you. Talk to your own GP, pharmacist or nurse about your own health.
- Need help now but it's not an emergency? Call NHS 111 or use 111.nhs.uk.
- Emergency? Call 999 or go to A&E.