Irritation can also be reduced by avoiding harsh facial cleansers and wearing sunscreen prior to sun exposure.One in 500 people experience hypersensitivity to BPO and are liable to experience burning, itching, crusting, and possibly swelling. About one-third of people experience phototoxicity under exposure to ultraviolet (UVB) light. Dosage
In the U.S., the typical concentration for benzoyl peroxide is 2.5% to 10% for both prescription and over-the-counter drug preparations that are used in treatment for acne. Other medical uses
Benzoyl peroxide is used in dentistry as a tooth whitening product. Non-medical uses
Bleaching
Like most peroxides, it is a powerful bleaching agent. It has been used for the bleaching of flour, fats, oils, waxes, and cheeses, as well as a stain remover. Polymerization
Benzoyl peroxide is also used as a radical initiator to induce chain-growth polymerization reactions, such as for polyester and poly(methyl methacrylate) (PMMA) resins and dental cements and restoratives. It is the most important among the various organic peroxides used for this purpose, a relatively safe alternative to the much more hazardous methyl ethyl ketone peroxide. It is also used in rubber curing and as a finishing agent for some acetate yarns. Safety
Explosion hazard
Concentrated benzoyl peroxide is potentially explosive like other organic peroxides, and can cause fires without external ignition. The hazard is acute for the pure material, so the compound is generally used as a solution or a paste. For example, cosmetics contain only a small percentage of benzoyl peroxide and pose no explosion risk.
Benzoyl peroxide is a chemical compound (specifically, an organic peroxide) with structural formula  (C6H5−C(=O)O−)2, often abbreviated as (BzO)2. In terms of its structure, the molecule can be described as two benzoyl (C6H5−C(=O)−, Bz) groups connected by a peroxide (−O−O−). It is a white granular  solid with a faint odour of benzaldehyde, poorly soluble in water but soluble in acetone, ethanol, and many other organic solvents. Benzoyl peroxide is an oxidizer, which is principally used as in the production of polymers.As a bleach, it has been used as a medication and a water disinfectant. In specialized contexts, the name may be abbreviated as BPO. As a medication, benzoyl peroxide is mostly used to treat acne, either alone or in combination with other treatments. Some versions are sold mixed with antibiotics such as clindamycin. It is on the WHO List of Essential Medicines, and, in the US, it is available as an over-the-counter and generic medication. It is also used in dentistry for teeth whitening. Benzoyl peroxide is also used in the plastics industry and for bleaching flour, hair, and textiles. It is also used to remove stubborn stains from dolls and other plastic toys, although some users have claimed that the product has unwanted long-term effects of discolouring the item, particularly with the My Little Pony brand. History
Benzoyl peroxide was first prepared and described by Liebig in 1858.