Hair is given a lighter color by bleaching it. Melanin pigments, which give hair a darker color, can be broken down with oxidation. The oxidizing agent used to bleach hair is hydrogen peroxide. It is mixed with ammonia to create an alkaline solution and to speed up the reaction.
There are four main hair colors: blonde, brunette, red, and black and these colors can be changed slightly in tone to create a different appearance.
Hair dyes can cause hair damage. Practicing hair-friendly techniques like limiting heat styling and conditioning the hair can help minimize damage whenever possible. Dyeing your hair closer to its natural color may also limit time exposure to hair dyes and help minimize damage.