Which chemical product is often used to lighten hair?

The correct choice is bleach, which is a chemical product specifically designed to lighten hair. Bleach works by breaking down the natural pigments in the hair. It contains powerful oxidizing agents that penetrate the hair shaft, effectively removing color. This is essential for creating lighter shades or achieving a blonde look, especially on darker hair.

Dye is primarily used to change the color of hair rather than lighten it. While some hair dyes may contain lightening agents, they generally do not remove the pigment as effectively as bleach does. Developer is typically used in conjunction with hair dye or bleach to activate the color but isn’t a standalone product for lightening hair. Conditioner, on the other hand, is used to moisturize and improve hair health but does not have any lightening properties. Thus, when it comes to lightening hair specifically, bleach is the most effective and commonly used product.