Hair straightening is a hair styling technique which involves the flattening and straightening of hair in order to give it a smooth, streamlined and 'sleek' appearance. It may be accomplished by using hair irons and hot combs, chemical relaxers, Japanese hair straightening, or Brazilian hair straightening. In addition, some shampoos, and conditioners and hair gels can help to make hair temporarily straight. Hair straighteners won't damage hair unless used with protective thermal spray. Also, hair should be trimmed regularly to prevent split ends.
During much of the 20th century, social norms encouraged African-Americans to straighten the tightly curled texture of their natural hair, resulting in artificial styles such as the conk. Although straightened hair was generally considered a black hair style as opposed to an imitation of white hair, the Black Power movement in the 1960s increased the acceptance of unstraightened, "natural" hairstyles such as the Afro and dreadlocks. Nevertheless, many African-American women still continue to straighten their hair as an aesthetic choice.
Hair straightening became more popular in the United States during the mid-late 1990s and through to the 2000s, whereas perming and curlier hair had previously been more popular fashions during the 1980s, even among men (for example, hair metal bands). However, both straight and wavy/curly hair can be achieved with use of a hair iron, and so it may be said that both straight and curly or wavy hair styles co-exist in modern fashion.