Definition of Benzoyl Peroxide


Benzoyl peroxide (BPO) is a compound that enjoys widespread use as a treatment for acne and other skin conditions. BPO is also used by the food industry, in hair bleaching products and as a polymerization agent. There has been some debate as to the relative safety of using products that contain this compound.

Chemical Composition

A peroxide derivative, benzoyl peroxide consists of two benzoyl groups linked by a peroxide chain. A benzoyl group, as defined by, is the univalent radical derived from benzoic acid. A peroxide chain is a term to describe the single bond oxygen-oxygen structure of the chemical peroxide. Hydrogen peroxide, though often shortened to peroxide in common usage, is a separate compound containing peroxide.

Dermatological Uses

The release of oxygen from benzoyl peroxide provides an important application that can be used as a topical antibacterial for burns. It is also useful as a dermatological agent for the treatment of poison ivy and acne. BPO has a keratolytic function that promotes softening and dissolution of the horny layer of the epidermis, also known as keratolysis. There are various gels, creams, lotions, soaps, masques and shaving creams that contain BPO in formulations for many applications. Benzoyl peroxide can be found in both over-the-counter and prescription-strength acne treatments.

Bleaching Agent

Benzoyl peroxide has been in use for over 50 years by the food industry as a bleaching agent in flour, whey processing and milk for the making of Italian cheeses. The compound, in its form as a flammable white granular solid, achieves this result through the release of oxygen as it decomposes.

Safety Issues

Studies of the long-term effects of benzoyl peroxide led to concerns over the potential of BPO to lead to skin cancer. This concern was largely based on the discovery that BPO produces free radicals, which have been directly linked to cancer. Prior to 1991, the U.S. Food and Drug Administration had labeled the product safe to use without concern. In light of the discovery that it produced free radicals, BPO had been downgraded in 1995 by the FDA to a status of “safety unknown” and required a warning label.

Current FDA Classification

The latest ruling by the FDA concerning the safety of over-the-counter benzoyl peroxide was issued in the March 4, 2010 edition of the Federal Register. The agency declared that benzoyl peroxide is “generally recognized as safe and effective.” This ruling officially takes effect on March 4, 2011. This means that products containing concentrations of BPO between 2.5 and 10 percent are now considered safe for the treatment of acne. This brings benzoyl peroxide back into category I status (GRASE) from the previous category III classification.