Nanoparticles have a high affinity to the horny layer of the skin and are used as transport systems which help the different active agents to penetrate the skin more easily. Nanoparticles are capsules shaped by a monolayer membrane. This monolayer membrane consists of a substance that is found in the basic structure of cell membranes of every organism in nature. This natural substance has a complex name that is as hard to spell as to pronounce: phosphatidylcholine.