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Heart & Circulation

LDL Cholesterol

LDL is the "bad" cholesterol — when there is too much, it slowly builds up in the walls of your arteries and raises your risk of heart attack and stroke. You are probably hoping for a simple "is my number OK?", and the honest answer for cholesterol is that there is no single safe number for everyone. What matters is your LDL together with your age, blood pressure and other risks, which your GP adds up to set a target that is yours. This page helps you read your number and know what to ask.

Standard Care
CategoryHeart & Circulation
Reference rangeSee your report
Evidence✓Standard Care
Last updated3 July 2026
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Australian adults have high LDL cholesterol (defined as 3.5 mmol/L or above), based on the 2011–12 Australian Health Survey.

What is ldl cholesterol?

LDL stands for low-density lipoprotein — think of it as a tiny carrier that moves cholesterol around your bloodstream. When there is more LDL than your body can use, the spare cholesterol can settle into the walls of your arteries and slowly form a fatty deposit called plaque. Over years that plaque narrows the vessels (doctors call this atherosclerosis), which is what links high LDL to heart attack and stroke. You do need some cholesterol — it helps build your cells and make hormones — but a high LDL is also one of the most changeable risk factors for heart disease, which is encouraging.

Why is it tested?

LDL is measured as part of a cholesterol blood test to get a read on your heart and blood-vessel health. On its own, a cholesterol number does not tell the whole story, so your GP feeds it into the Australian cardiovascular disease (CVD) risk calculator at cvdcheck.org.au, along with your age, blood pressure, whether you smoke, and whether you have diabetes. Together those give your real risk over the next few years — and a target for your LDL that fits you, rather than a one-size line. The test is also used to see whether changes you have made, or a medicine, are having a measurable impact.

Reference range (Australia)

Risk-based — no single 'normal'. For population context, an LDL of 3.5 mmol/L or above is classed as high; your personal target is set by your GP from your overall cardiovascular risk mmol/L

Australia uses risk-based LDL targets rather than one universal "normal" value, and the 2023 CVD risk guideline does not set a fixed LDL number. Common practice references a treatment target below 2.0 mmol/L, with lower targets (for example below 1.4 mmol/L) for the highest-risk people such as those with established heart disease, and more permissive targets (below 3.0 mmol/L) at lower risk. Use the interval on your report and ask your GP what target applies to you.

Reference intervals vary between laboratories. Always use the range printed on your own report.

What your result means

If your level is low

A low LDL is generally good news for your heart. Your GP will still look at the full picture — your HDL ("good") cholesterol, triglycerides, blood pressure and family history — to understand your overall risk. A very low LDL is unusual unless you are taking cholesterol medication, and it is rarely something to worry about.

If your level is in range

An LDL that is not adding much to your heart risk right now is reassuring. Risk does change over time, though. A Mediterranean-style way of eating, regular movement, a healthy weight and not smoking are all linked with lower heart risk, and your GP can check in with you as you get older or if your health changes.

If your level is high

A higher-than-usual LDL means there is more "bad" cholesterol around to settle into your artery walls. How much that matters depends on the rest of your picture — your age, blood pressure, whether you smoke, and your family history — so your GP works out your personal target and what, if anything, to do. The reassuring part is that LDL is one of the most changeable numbers on your results: things like diet (less saturated and processed fat, more fibre) and regular activity all influence it, and for some people a cholesterol-lowering medicine is part of the plan your GP discusses. This is a conversation to have with your GP, not a number to act on alone.

What can affect your result

A few things move your LDL. Diet is the big one you can change: saturated and processed (trans) fats push it up, while fibre and plant sterols help bring it down. Carrying extra weight and not moving much tend to raise it, and it also drifts up naturally as you get older. Genetics matter too — some people inherit a condition called familial hypercholesterolaemia (about 1 in 250 Australians) that keeps LDL high no matter how well they eat, and usually needs medication. An underactive thyroid (hypothyroidism) and kidney disease, plus a handful of medicines, can nudge LDL as well. Your GP weighs all of this up when reading your result.

When to act

If your LDL is above the target your GP has set for you, that is a moment for a chat rather than alarm. Diet is often where GPs start — things like less saturated and trans fat, more soluble fibre, and foods with added plant sterols, alongside regular movement and a healthy weight. If that is not enough, or your overall risk is high, your GP may talk through a cholesterol-lowering medicine. A repeat test down the track shows whether things are heading the right way. This page is general information and is not a substitute for advice from your GP.

Frequently asked questions

LDL is a tiny carrier that moves cholesterol through your blood. It earns the "bad" nickname because when there is too much, cholesterol settles into your artery walls and forms plaque that narrows the vessels — which raises the risk of heart attack and stroke. HDL does the reverse, helping clear cholesterol out, which is why it is called the "good" one.

There is no single "normal" LDL that applies to everyone — and that is not a dodge, it is how cholesterol actually works. Your target depends on your overall heart risk, which your GP works out with the Australian risk calculator. As a rough guide, once someone is on treatment a target below 2.0 mmol/L is common, and people at higher risk aim lower. The number that matters is the one your GP sets for you.

Your GP uses the Australian cardiovascular disease (CVD) risk calculator (cvdcheck.org.au), which combines your age, sex, blood pressure, smoking, diabetes and cholesterol to estimate your risk over the next 5 years. The higher that risk, the lower the LDL target they will aim for.

For many people diet does make a difference, especially if LDL is only mildly raised. Diets lower in saturated and trans fat and higher in soluble fibre and plant sterols, with regular movement and a healthy weight, are linked with lower LDL. Genetics have a say too, though: people with familial hypercholesterolaemia usually need medication as well as diet. Your GP can tell you which is more likely for you.

Familial hypercholesterolaemia (FH) is an inherited condition where LDL runs high from birth because the body clears it less well. It is more common than people think — about 1 in 250 Australians — and most do not know they have it. It is worth asking your GP about FH if your LDL is very high (more than 5 mmol/L), or if heart attacks or high cholesterol run in your family young.

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