Hydrogen Peroxide (HP) and Carbamide Peroxide (CP) – What Is The Difference?

The difference between hydrogen peroxide and carbamide peroxide


Hydrogen peroxide is a powerful oxidizing agent. Its whitening effect occurs because oxygen free radicals break down larger pigment molecules into smaller, less noticeable ones.

Carbamide peroxide consists of hydrogen peroxide combined with urea. The urea component stabilizes the formula, resulting in a more consistent and extended shelf life compared to hydrogen peroxide alone.

The Science

Hydrogen peroxide and carbamide peroxide are both commonly used in teeth whitening products, but they have differences in their chemical composition and how they function in whitening treatments:

Hydrogen Peroxide:

  • Chemical Composition: Hydrogen peroxide (H2O2) is a simple compound composed of hydrogen and oxygen molecules.
  • Whitening Action: It is a potent whitening agent that directly breaks down into water and oxygen upon application. The released oxygen molecules penetrate the enamel, oxidizing and breaking down stain molecules, resulting in a lighter tooth color.
  • Strength: Generally, hydrogen peroxide is more potent than carbamide peroxide when comparing equal concentrations. For example, a 10% hydrogen peroxide solution would typically be stronger than a 10% carbamide peroxide solution.
  • Faster Acting: Due to its more immediate breakdown, hydrogen peroxide tends to act more quickly compared to carbamide peroxide.
  • Shorter Wear Time: Whitening treatments with hydrogen peroxide often require shorter wear times because of its faster action.

Carbamide Peroxide:

  • Chemical Composition: Carbamide peroxide (CH6N2O3) is a compound containing urea hydrogen peroxide and serves as a slow-release form of hydrogen peroxide.
  • Whitening Action: When applied, carbamide peroxide breaks down into hydrogen peroxide and urea. The hydrogen peroxide is responsible for the whitening action, similar to how hydrogen peroxide functions, but it releases the hydrogen peroxide more gradually over time.
  • Stability: Carbamide peroxide is more stable than hydrogen peroxide and tends to have a longer shelf life. This stability allows it to be used in at-home whitening products that can be stored for longer periods.
  • Longer Duration: Due to its slower release of hydrogen peroxide, carbamide peroxide treatments generally require longer wear times to achieve similar results to those obtained with hydrogen peroxide.

Both hydrogen peroxide and carbamide peroxide can effectively whiten teeth when used correctly and in appropriate concentrations. The choice between the two often depends on the desired treatment duration, sensitivity concerns, and the convenience of wear times for the individual.

Consulting with a dentist can help determine which option is best suited for specific whitening needs.