Hair perm can add body to hair, make it more curly, or wavy and enhance a person's looks greatly. Perms involve breaking down the links that bind the keratin chains in hair. Networks of disulphide links, saline and hydrogen bonds provide the cohesion of keratin chains. The disulphide links are characteristic features of the keratin structure and are the most solid. The saline bonds are electrostatic bonds, which diminish greatly when hair is immersed in water. In an acid or alkaline environment, they disappear completely. Perming causes permanent deformation by breaking the disulphide links which are then reconstituted to set them in their present form. After a perm, appropriate care of the hair must be taken to minimize the damage.

Hair coloring can cover white hair, darken or lighten the hair color, or provide highlights in the hair for better shades or cutting effects. It involves chemicals and any permanent color change will alter the structure of hair. Effects depend on the natural color and condition of hair. All permanent colorants have a toxic base which is a Para compound. Because of the toxic element some people can be allergic to these dyes, but such reaction is very rare. The Para compound dyes are often known as oxidation dyes because of the use of hydrogen peroxide to activate them.
They penetrate the cuticle, and then react with the hydrogen peroxide and the natural pigmentation within the cortex to form the color that becomes permanent. Semi-permanent colors only penetrate the cuticle and the outer layer of the cortex, and do not chemically alter the hair structure or the natural pigment. It should last for about 8 shampoos only. All colorants are save to use. A study of 99,000 women has found no evidence that long-term use hair dye can cause certain types of cancer.

Bleaching will reduce color in stages from brown, red, orange, through to yellow, until almost all the color goes. The stronger the mixture, the faster and lighter the results in color. Bleaching is use to remove pigment from the hair. A bleaching agent is made up of bleaching powder or bleaching cream plus hydrogen peroxide.