Micelles and liposomes can serve as vehicles used to solubilize and carry bioactive compounds to their site of action, thus increasing their bioavailability. First experience has been made using vitamins and enzymes as functional food additives. Moreover, micelles could be useful to deliver drugs to a defined site of action, thus reducing frequently occurring side effects of systemic drug administration. Micelles are true nano-materials with a size range of 10 to 30 nm in diameter. Ideally, they should have a narrow size distribution. Furthermore, they have to be stable and should release their active compound only in the target region. Characterization of the micelle suspensions is vital to guarantee these properties and has to cover several aspects. One important point is size distribution, which has to be determined with high resolution more