What chemical is most commonly found in products used for hair bleaching?

Hydrogen peroxide is the chemical most commonly found in products used for hair bleaching due to its effectiveness as a lightening agent. When applied to hair, hydrogen peroxide works by breaking down the melanin pigments that give hair its color, leading to a lighter shade.

In the context of hair bleaching, hydrogen peroxide serves as an oxidizing agent, which means it creates an environment in which the melanin can be lifted and lightened effectively. It is crucial in many formulations because it can be combined with other chemicals, such as ammonia, to enhance the lightening process and create a manageable pH level for hair treatment.

While ammonia is also commonly used in hair bleach to open up the hair cuticle and allow the harsh chemicals to penetrate the hair shaft, it is not the primary agent responsible for the bleaching effect itself; rather, it works in conjunction with hydrogen peroxide. Calcium hydroxide and peracetic acid are not standard ingredients found in hair bleach products or commonly used for this specific purpose, making them less relevant to the function of hair lightening. Therefore, hydrogen peroxide stands out as the key chemical in hair bleaching products.