1991 advert for Oxy 10 featuring the very young ex Easeenders star Nicola Stapleton aka Mandy Salter.

Benzoyl peroxide (pronounced /ˈbɛnzɔɪl pəˈrɒksaɪd/) is an organic compound in the organic peroxide family. It consists of two benzoyl groups joined by a peroxide group. Its structural formula is [C₆H₅C(O)]₂O₂. It is one of the most important organic peroxides in terms of applications and the scale of its production. Benzoyl peroxide is used as an acne treatment, for improving flour, for bleaching hair and teeth, for polymerising polyester and many other uses.

Zit Treatment

Jack Breitbart of Revlon laboratories first developed the use of benzoyl peroxide for treating acne in the 1920s. It is typically placed over the affected areas in gel or cream form, in concentrations of 2.5% increasing through the usually effective 5% to up to 10%. Research suggests that 5 and 10% concentrations are not significantly more effective than 2.5% and 2.5% is usually better tolerated. It commonly causes initial dryness and sometimes irritation, although the skin develops tolerance after a week or so. A small percentage of people are much more sensitive to it and liable to suffer burning, itching, peeling and possibly swelling. It is sensible to apply the lowest concentration and build up as appropriate. Once tolerance is achieved, increasing the quantity or concentration a second time and gaining tolerance at a higher level usually gives better subsequent acne clearance. Benzoyl peroxide works as a peeling agent, increasing skin turnover and clearing pores, thus reducing the bacterial count there as well as directly as an antibacterial.

Other common uses for benzoyl peroxide include dying hair, and as an active ingredient in teeth whitening systems. It is also used in the preparation of flour, and can be used as an initiator and catalyst for polyester thermoset resins (as an alternative to the much more hazardous methyl ethyl ketone peroxide).

In the U. S., the typical concentration for benzoyl peroxide is 2.5% to 10% for both prescription and over the counter preparations that are used in treatment for acne. Higher concentrations are used for hair bleach and teeth whitening. Benzoyl peroxide, like most peroxides, is a powerful bleaching agent. Contact with fabrics or hair can cause permanent color dampening almost immediately. Even secondary contact can cause bleaching. For example, contact with a towel that has been used to wash off benzoyl peroxide-containing hygiene products.