LDL is a lipoprotein particle that carries cholesterol into peripheral tissue cells and can be oxidized to oxidized LDL. When there is an excess of LDL, especially oxidized LDL, the cholesterol it carries accumulates in the arterial walls, which can easily cause atherosclerosis over time. Therefore LDL is also known as bad cholesterol. There are four types of fats in human blood, cholesterol, neutral fat, free fatty acids and phospholipids. The total amount of cholesterol in the human body is 100-200g. Cholesterol must be combined with lipoproteins to be transported to the body. Lipoproteins, which are subdivided into LDL and HDL, etc.