Silicon-containing particles are used for protection of human cells from electromagnetic radiation in the UV range and optionally in the visible as far as the IR range, where the particles preferably take the form of clusters of primary particles having a particle size in the range from 5 to 100 nm. A particular advantage is the possibility of matching the absorption of the electromagnetic radiation to the wavelength region to be absorbed in a defined manner via the particle size. The silicon-containing particles can be used for biocompatible and biodegradable UV protection in cosmetic or medical formulations, such as preferably a sunscreen, or else in a cosmetic formulation for the UV protection of hair.
