"Hair build up" is a noun that describes the accumulation of styling products, natural oils, and environmental debris on the scalp and hair. This build up can weigh hair down, making it look dull, greasy, and lifeless.
Hair build up is a common problem that can affect people of all ages and hair types. It can be caused by a number of factors, including the use of heavy styling products, infrequent shampooing, and exposure to pollution. Hair build up can also be a symptom of an underlying scalp condition, such as dandruff or psoriasis.