Hair bleaching is a process of lightening up the colour of the hair, which is determined by the quantity, type and distribution of colour pigment inside the hair. This process radically alters the original proportion of the melanin pigment and the bleached hair that will be more fragile and drier after bleaching as the bleach reacts with the hair proteins and reduces their molecular weight. Hair bleaching makes the hair more brittle and weaker. Treatment is usually required after the bleaching.
Attribution: Straight Talk Foundation