Using the term hypercholesterolemia refers to an excess of cholesterol in the blood, a phenomenon that occurs when total cholesterol levels (LDL or HDL) are too high. Cholesterol is a fat present in the blood, whose largest part is produced by the body and only a small amount is obtained through diet.

Cholesterol contributes to the proper functioning of the body, but in excess it represents a risk factor for heart disease because of the process of atherosclerosis. Excess cholesterol deposits on artery walls form lesions that thicken and stiffen the walls of the vessels. Atherosclerosis can cause actual plaque formation over time, which prevents or stops blood flow, with consequent risks to the cardiovascular system.

Cholesterol in the blood is transported within molecular structures called lipoproteins. The low density lipoprotein or LDL ('bad' cholesterol) carries excess cholesterol from the liver to the arteries and release it into the vessels resulting in atherosclerosis. The high density lipoproteins or HDL ('good' cholesterol), facilitate the removal of cholesterol from the blood and its elimination through bile salts, protecting the heart and blood.