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Benzoyl Peroxide

Last updated date: 17th Apr 2024
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What is Benzoyl Peroxide? 

Benzoyl Peroxide is an organic compound with structural formula C₅H₅−C(=O)O−)₂, abbreviated as BzO₂. It is a peroxide with a keratolytic, comedolytic, antibacterial, irritant, and anti-inflammatory action. It decomposes to release oxygen which is lethal to the bacteria Propionibacterium acnes. Benzoyl Peroxide appears as odourless white granules or powder. It is sparingly soluble in water. It enhances the turnover rate of epithelial cells, through peeling the skin. The Benzoyl Peroxide is an oxidizer, which is generally utilised in the generation of polymers.

Structure of Benzoyl Peroxide

The chemical structure of a molecule in the Benzoyl Peroxide involves the arrangement of the atoms and the chemical bonds that holds all the atoms collectively. The Benzoyl Peroxide molecule comprises 29 bonds. There are 14 multiple bonds, 5 rotatable bonds, 19 non-H bonds, 2 double bonds, 12 aromatic bonds, and 2 six-membered rings. In the structure of Benzoyl Peroxide, the carbon atoms are intended to be placed at the edges, and the hydrogen atoms attached to carbon atoms are not indicated. Each carbon atom is estimated to be associated with sufficient hydrogen atoms to render the carbon atom with 4 bonds. 

Properties of Benzoyl Peroxide

The Physical and Chemical Data of Benzoyl Peroxide are given below.

Molecular Formula


Molar Mass

242.23 g/mol

Melting Mass

103-105 °C


1.334 g/cm3

Solubility in Water

Sparingly soluble (20 °C)

Chemical Composition

  • Sodium hydroxide

  • Hydrogen peroxide

  • Benzoyl chloride

  • Carbomer 940

  • Benzoic acid

  • Phenylacetone

Boiling Point



Colourless Solid

Chemical Properties of Benzoyl Peroxide

  • Benzoyl Peroxide is an explosive and hazardous chemical compound.

  • It causes swelling of the skin.

  • Benzoyl Peroxide is prepared by the treatment of Benzoyl Chloride with Barium Peroxide.

  • This compound readily supports homolytic fission to yield free radical products that are incredibly reactive.

  • As it contacts human skin, it breaks down to produce oxygen and benzoic acid.

Physical Properties of Benzoyl Peroxide 

  • Benzoyl peroxide has a colourless crystalline structure.

  • It has a faint odour with a smell of benzaldehyde.

  • It is insoluble in water and slightly soluble in alcohols.

  • It is considerably soluble in chloroform and ethers. 

  • The dry form of Benzoyl Peroxide is highly reactive and can explode. 

  • Benzoyl Peroxide melts within 103 °C and 106 °C with dissolution.

  • 1 g Benzoyl Peroxide fluxes in 40 ml of Carbon Disulfide.

Uses of Benzoyl Peroxide

Benzoyl Peroxide was first prepared by Liebig in 1858. Treatment with Benzoyl Peroxide was introduced for wounds by Peck and Chagrin in 1934, and for acne varioliformis and sycosis Vulgaris by Reynolds and Lyon in 1929.

Benzoyl Peroxide is an effective organic peroxide because of its wide variety of uses. It is also manufactured on a large scale industrially. Some of the uses of this organic compound are listed below.

  • This organic compound can be applied to human skin to treat acne if the concentrations are between 2.5% to 10%.

  • Benzoyl Peroxide is used to extract ink and dye stains from many gadgets such as vinyl dolls.

  • Benzoyl Peroxide is used as a bleaching agent in bread and cheese. 

  • It is used in cosmetic hair colouring and tooth whitening processes. 

  • It is also a very useful oxidant.

  • With the help of the Benzoyl Peroxide, the polymerization process of resins can be started. 

  • In the synthesis of thermosetting polyester resins, it can also be used as a catalyst.

Benzoyl Peroxide Side Effects 

Some of the side effects of benzoyl peroxide are given below.

  • Dry skin

  • Skin Irritation

  • Red skin or flaying skin

  • Skin Blisters 

  • Swollen skin, tongue, face,  or throat

  • Severe Dizziness

  • Breathing Problems

FAQs on Benzoyl Peroxide

Q1. How to Use Benzoyl Peroxide Cream or Gel?

Answer: Benzoyl Peroxide products are available as cleansers, foam, or lotion. Some products require a prescription, and some can be purchased without a prescription. To use the benzoyl peroxide cream, we need to wet the area of treatment, then take a small amount of the lotion in our hands and smoothly massage in the affected area. We should keep the liquid on our skin for 1 or 2 minutes and then rinse off the skin thoroughly with water and gently pat the area dry with a towel. 

Q2. What are the Uses of  Benzoyl Peroxide?

Answer: Benzoyl Peroxide is used for skin treatment. We should always wash our hands before and after using Benzoyl Peroxide. If the skin starts peeling off or gets dry, Benzoyl Peroxide should be used as it helps to treat the dry skin. Benzoyl Peroxide can also discolour or bleach our hair, towels, clothes, and bedding. It should be kept away from coloured fabrics and hair. With the help of the Benzoyl peroxide, the polymerization process of resins can also be started. Benzoyl Peroxide can also be used as a bleaching agent in bread and cheese.