There is a common misconception that brushing wet hair or wet hair extensions is damaging. The truth is, human hair becomes more fragile when its wet which has led to the belief that brushing it in this state could be harmful, however not brushing the hair after washing, especially if it is knotty, can cause matting once the hair is dry. As long as the correct hairbrush is used and the hair is brushed in the correct way, no damage should occur.