All processed human hair wigs and toppers will lose colour and fade out; they will also oxidise (go brassy). The rate in which this happens differs from wig to wig and is also influenced by your environment and how you look after them (remember that 99% of wigs are made from several different people's hair). This process cannot be stopped, but it can be slowed down by using products that contain UV filters and thermal protectors such as Neal and Wolf.