Which statement is true about lighteners?

Lighteners are specifically designed to diffuse or remove pigment from the hair. This process is essential for various hair coloring techniques, especially when a lighter shade is desired. Lighteners work by breaking down the melanin (the natural pigment in hair) to achieve a lighter color. This ability to remove or alter pigment makes lighteners a foundational product in salon coloring services, whether for creating highlights, balayage, or preparing hair for further dyeing.

The other statements do not accurately describe the function or characteristics of lighteners. For example, while lighteners can assist in managing grey hair by removing underlying pigment, their primary purpose is not to add color but to lighten existing pigment. Lighteners are not limited to a semi-permanent formulation; they are available in various forms, including permanent and powder lighteners. Additionally, not all lighteners are safe for every hair type; different formulations may be more or less suitable depending on the hair's condition and texture. Thus, understanding the primary function of lighteners as agents for pigment removal is essential for effective hairstyling and coloring.