Relaxers are chemical treatments used to straighten curly or wavy hair. They work by breaking down the protein structure of the hair, allowing it to be reshaped. This process can make hair more manageable and easier to style, but it can also lead to damage if not applied correctly. There are two main types of relaxers: lye and no-lye. Lye relaxers contain sodium hydroxide, while no-lye relaxers use calcium hydroxide or guanidine hydroxide. Both types require careful application and maintenance to ensure hair health and prevent excessive dryness or breakage.