Cholesterol: The Good and the Bad Cholesterol is chemical your body needs to build cells and produce hormones. It travels through the bloodstream attached to particles called lipoproteins. One important type is Low-Density Lipoprotein (LDL) - often called the “bad cholesterol.” LDL particles contain a protein called Apolipoprotein B (ApoB), which helps them bind to cells throughout the body. For decades, LDL has been considered harmful because it can deposit cholesterol i