Lipid compositions with the ability to self-assemble into biocompatible nano- and mesostructured functional materials have many potential uses in modem medicine. By using two-component lipid systems, it is possible to tune the structure formation and related functional properties, e.g., the encapsulation and extended release of small molecules and peptides, by simply varying the ratio of the lipid building blocks. This is shown in detail for the binary phosphatidylcholine and diglyceride lipid systems, which are currently being used in multiple programs for the development of novel pharmaceuticals and marketed products.