At the basic level, phospholipids are a phosphate group (phospho) attached to fatty acids (lipids) by means of a glycerol group.
Unlike phosphates, which are attracted to water (hydrophilic), fatty acids are repelled by water (hydrophobic). It is this very love/hate relationship with water that allows phospholipids to form cellular membranes — and liposomes as well.
As phospholipids are exposed to water-based solutions, they automatically align themselves in a double-layer (bilayer) configuration – phosphates toward the water and fatty acids away from the water.
One of the most important and prominent phospholipids in cell membranes is called phosphatidylcholine (PC) [pronounced FOSS-fah-tide-al-KOH-lean]. At birth up to 90% of cellular membranes are made up of PC. As humans age, the percentage of PC in their cellular membranes can decrease to about 10%. This fact leads many to recommend consistent supplementation with this essential phospholipid.