HDL cholesterol gets its reputation as the ”good” cholesterol because it has a certain protective function. HDL or High-Density Lipoprotein is a particle which is composed of multiple proteins and lipid molecules (cholesterol for example). Cholesterol is transported through blood in the monolayer surface of the lipoprotein particle because of his water-insoluble properties. HDL particles are sometimes called "good cholesterol" because they can transport fat molecules out of artery walls decreasing the possibility for atherosclerosis.