Hair straightening is a hair styling technique used since the 1890's which involves the flattening and straightening of hair in order to give it a smooth, streamlined, and 'sleek' appearance. It was made by Garret A. Morgan, to help African American manage their hair.

It became very popular among blacks male and female and females of all races, during the 1950's, because black people wanted to have the very popular and stylish "greaser"look, either that or wearing Afros.
It accomplished using a hair iron or hot comb, chemical relaxers, Japanese hair straightening, or Brazilian hair straightening. In addition, some shampoos, conditioners, and hair gels can help to make hair temporarily straight. The process is often called "rebonding" in Southeast Asia.

If done often, flat irons and chemicals can be damaging to hair. Excessive straightening often results in split ends. However, heat protectant sprays can decrease the damage.

There are two Methods and Permanent.

Hair irons and hot combs can only temporarily modify the shape/texture of hair. The straightened effect will be reversed by environmental factors, mainly contact with water from washing, rain, humidity, etc. This includes water in styling products such as gels applied after straightening, although careful use of such treatments can still produce usable results not much different from if the user had naturally straight hair before applying the product.

At many hair salons they have the Keratin Hair Treatments. They will usually last to about 2 1/2 months. This treatment helps to make sure that you do not need to straighten your hair often. During the treatment, the hair stylist will add a protein to your hair called Keratin. To have this process last, they need to straighten your hair very carefully afterward. Depending on your hair stylist, they will tell you a certain amount of time before you can wash your hair, usually around 3-4 days. To help maintain your hair treatment longer, you can buy special shampoos and conditioners that you should ask your hair stylist about. This treatment will help your hair stay healthy because you will not be applying heat to it.

Relaxers and the other methods permanently alter the structure of the hair, although new hair growth is not affected. The drug interferon alpha has been reported as being shown to modify hair follicles causing permanent change in a person's hair texture.