Cholesterol is transported via lipoproteins. There are multiple types of lipoproteins and they each have slightly different functions: high-density lipoprotein (HDL), low-density lipoprotein, LDL, very low-density lipoprotein (VLDL). LDL cholesterol is considered bad cholesterol because as it travels through the blood, it deposits cholesterol into the lining of blood vessels, causing atherosclerosis and an increase in cardiovascular disease.