Benzoyl peroxide is used as an acne treatment in cleansers, astringents, and moisturizers. The typical concentration for benzoyl peroxide is 2.5% to 10% for both prescription and over the counter use in treatment for acne. Higher concentrations are used for hair bleach and teeth whitening.

In treatment of acne, benzoyl peroxide works as a peeling agent, increasing skin cell turnover and clearing pores from dead skin cells and stale sebum on which P.acnes bacteria feed, thus reducing the bacterial count. Benzoyl peroxide also kills bacteria on skin surface.

Benzoyl peroxide is usually prepared by reacting sodium peroxide with benzoyl chloride. Chemical science warns that benzoyl peroxide is highly flammable, explosive, toxic, a possible tumor promoter and may act as a mutagen - that is, it may promote cancerous mutations of skin cells.

While benzoyl peroxide may kill the bacteria and relieve the inflammation, it is a strong irritant that may actually trigger acne and make it worse. In a 1977 study, 76% of participants treated with benzoyl peroxide developed a contact dermatitis caused by allergic reaction to benzoyl peroxide. The symptoms included burning, itching, peeling and swelling.

 

The worst thing about benzoyl peroxide is its ability to increase free radical damage and thus increase the risk of skin cancer. By stripping the skin of its natural protective mantle, benzoyl peroxide makes it more vulnerable to UV radiation and air pollution.

Besides, due to its chemical structure, benzoyl peroxide generates free radicals directly on skin surface. Doubled by sun exposure, the oxidative stress from benzoyl peroxide can cause irreversible damage to skin that may eventually lead to skin cancer.

This is not an alarmist conclusion. Benzoyl peroxide has been linked to skin cancer since 1990s. Scientific publications call this chemical a free radical-generating skin tumor promoting agent. FDA studies found that "determined that the studies show that benzoyl peroxide is a skin tumor promoter in more than one strain of mice as well as in hamsters."

In 1990, the Journal of Investigative Dermatology reported about an experiment on mice receiving topical applications of benzoyl peroxide.

"Ten days later tumor promotion was begun by twice-weekly topical application of BPO (20 mg/animal)," reported scientists from Department of Dermatology, Skin Disease Research Center, University Hospital of Cleveland in Cleveland, Ohio.

In 1995 the U.S. FDA stated that benzoyl peroxide is no longer safe for use. It is now classified as Category III (safety is uncertain) ingredient.

According to legislation, manufacturers and product marketers must provide this information to skin care professionals so that consumers can be advised of the potential dangers.

Basically, the products containing benzoyl peroxide must carry a label with warnings, similar to those on cigarette packs. So far, nothing has happened.

Today, cancer-causing acne chemical benzoyl peroxide is present in the following products:
Rite Aid Acne Spot Treatment
ZAPZYT Maximum Strength Acne Treatment Gel
ZAPZYT Maximum Strength 10% Benzoyl Peroxide Acne Treatment Gel
Clean & Clear Maximum Strength Persa-Gel
Topix Benzoyl Peroxide Wash (various concentrations)
CVS Acne Treatment
Topix Benzaderm Gel (various concentrations)
Stiefel PanOxyl Stiefel PanOxyl Bar (various concentrations)
Stiefel PanOxyl Bar 5% acne treatment
DDF Medicated Skin Cleanser 10% with Tea Tree
DDF Benzoyl Peroxide Gel (various concentrations)
Oxy Balance Maximum Acne Treatment
Oxy Emergency Spot Treatment
MD formulations Benzoyl Peroxide 10
Peter Thomas Roth BPO Gel (various concentrations)
Jan Marini Benzoyl Peroxide 5% acne treatment
Stridex Power Pads
DDF Pumice Acne Scrub
DDF Medicated Shave Cream, BP 2.5% & Tea Tree Oil
Serious Skin Care Continuously Clear Clearz-it Acne Medication Daytime Blemish Preventor
BioElements Breakout Control Emergency Blemish Lotion with BP
B. Kamins Chemist Bio-Maple medicated acne gel (various concentrations)
Pevonia Botanica Spot Treatment
Pevonia Botanica Clarifyl Spot Treatment
Clearasil Maximum Strength Acne Treatment Cream, Vanishing
Johnson & Johnson Clean & Clear Daily Cleanser
Neutrogena On-the-Spot Vanishing Formula Acne Treatment
Earth Therapeutics First Aid Kit, Acne Treatment
Dermalogica special clearing booster acne treatment
N.V. Perricone M.D. Cosmeceuticals Acne Treatment Gel Cream
Acnefree Oil Free Purifying Cleanser
Rodan and Fields Unblemish Acne Lotion

If you don't want to deal with skin cancer later in your life, please avoid benzoyl peroxide and replace it with salicylic acid or tea tree essential oil, both proven antibacterial agents with very few side effects. 

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