HDL particles are organized into subclasses such as alpha-1, alpha-2, and pre-beta. These subclasses reflect differences in size and maturity. Alpha-1 HDL is one of the larger, more mature forms, and it has been consistently linked to beneficial cardiovascular functions, especially its ability to promote cholesterol efflux. Cholesterol efflux is the process by which HDL removes excess cholesterol from artery wall cells and transports it to the liver for disposal, a mechanism central to preventing plaque buildup and atherosclerosis.