What causes product build up on your hair?

Product build-up on hair is primarily caused by the accumulation of styling products, conditioners, and shampoos that contain heavy ingredients like silicones, oils, and waxes. Over time, these substances can layer on the hair shaft and scalp, making hair feel greasy, dull, or weighed down. Infrequent washing or using harsh shampoos can exacerbate the problem, as they may not effectively remove the residue. Environmental factors, such as pollution and hard water, can also contribute to build-up.