LDL cholesterolLDL-C · 'Bad' cholesterol

LDL cholesterol is the cholesterol carried by low-density lipoproteins (LDL). These particles ferry cholesterol to the body's tissues, and when there are too many of them they can lodge in artery walls and drive the fatty build-up behind heart disease.

It matters because LDL cholesterol is one of the best-evidenced causal factors in cardiovascular disease, and lowering it is among the most reliable ways to reduce that risk. That is why it is often called the 'bad' cholesterol — though the reality is more about particle number than a simple good/bad split.

In practice, LDL is read alongside HDL, triglycerides and ideally ApoB, which counts the atherogenic particles directly and can refine risk when LDL alone looks reassuring.