Updated on February 1, 2024
6 min read

Carbamide Peroxide for Teeth Whitening

NewMouth is reader supported. We may earn a commission if you purchase something using one of our links. Advertising Disclosure.

When it comes to tooth-whitening ingredients, most people have heard of hydrogen peroxide. This familiar household product is used for everything from disinfecting wounds to bleaching hair.

Carbamide peroxide isn’t as well-known as hydrogen peroxide, but it’s also used to whiten teeth. If you’re considering teeth whitening at home or with an in-office treatment, you may have to choose between hydrogen peroxide and carbamide peroxide bleaching agents. 

This article explains how hydrogen peroxide and carbamide peroxide differ so you can decide about teeth-whitening products.

Carbamide Peroxide vs. Hydrogen Peroxide 

Hydrogen and carbamide peroxide are two ingredients people commonly use to bleach teeth.

The primary difference is that carbamide peroxide takes longer to dissolve. Hydrogen peroxide releases most of its whitening power within 30 to 60 minutes. On the other hand, carbamide peroxide can take 8 hours to break down.

Here’s how the two compare:

What Is Hydrogen Peroxide?

Hydrogen peroxide is a powerful whitening agent. It’s an oxidizing agent, which means it causes a chemical reaction that makes the oxygen atoms lose electrons. In tooth whitening procedures, an oxidizing agent works by dissolving teeth stains.

Professional whitening systems often use hydrogen peroxide because it provides instant, white results.

What Is Carbamide Peroxide?

Carbamide peroxide is a combination of hydrogen peroxide and carbamide (urea). It has a slightly different chemical makeup but also works by dissolving teeth stains.

Similar to hydrogen peroxide, carbamide peroxide is an oxidizing agent. It removes stains the same way hydrogen peroxide does but at a slower rate. 

Carbamide peroxide is also an effective whitening agent. It contains hydrogen peroxide at a ratio of 1:3. For example, a product with 30% carbamide peroxide contains around 10% hydrogen peroxide.

Similarities Between Hydrogen Peroxide Carbamide Peroxide 

Hydrogen peroxide and carbamide peroxide share many similarities, including that they are:

  • Oxidizing agents
  • Equally effective at whitening teeth
  • Unnoticeable sensitivity differences

Neither hydrogen peroxide nor carbamide peroxide causes rebound. This is when the teeth look lighter immediately after a whitening treatment but lose brilliance quickly. Rebound is usually due to dehydration.

Differences Between Hydrogen Peroxide and Carbamide Peroxide

Differences between carbamide peroxide and hydrogen peroxide include:

  • Speed — Hydrogen peroxide breaks down quicker than carbamide peroxide. 
  • Treatment time — Hydrogen peroxide products are used for shorter periods per treatment, but that doesn’t alter the number of days it takes to whiten teeth.
  • Shelf life — Formulas with carbamide peroxide have a slightly longer shelf life than those with hydrogen peroxide.
  • Chemical composition — Carbamide peroxide contains hydrogen peroxide and carbamide.

Get your brightest smile with NewMouth's top teeth whitening picks for 2024.

Is Carbamide Peroxide Safe to Use on Teeth? 

Carbamide peroxide can be used safely for at-home treatments. However, we always recommend discussing at-home whitening with your dentist first.

Research shows that a 16 to 35% carbamide peroxide concentration is generally safe and effective for whitening teeth. A 35% concentration provides significantly more whitening effects without additional side effects.1

How Does Carbamide Peroxide Teeth Whitening Work?

Carbamide peroxide works by a process called oxidation. Oxidation is a chemical reaction that breaks down the molecules that cause discoloration on teeth.

This compound breaks down in contact with water to release hydrogen peroxide. 

Carbamide peroxide has an oxidizing power that is released in the first 2 hours. Afterward, it will last up to 6 hours to provide whitening effects.

4 Side Effects of Carbamide Peroxide 

Carbamide peroxide side effects are fairly common. For most people, they aren’t noticeable or harsh enough to stop them from using the products. To reduce side effects, whiten with peroxide less frequently or use lower concentrations. 

There are several side effects of carbamide peroxide whitening:

1. Gum Irritation

Gum irritation can occur from a poorly fitted whitening tray. It can also develop from the carbamide peroxide whitening product. 

If the whitening product touches your gums, you may experience irritation. Custom trays prevent this problem. They are scalloped along your unique gumline. 

Over-the-counter (OTC) whitening products typically use trays that overlap the gums. Rarely, ill-fitting trays (universal options) can rub against your gums and lead to an infection.

2. Sensitivity

This side effect includes sensitivity to air, thermal sensitivity, and tooth sensitivity:

  • Air sensitivity is experienced when you breathe through your mouth. 
  • Thermal sensitivity occurs when you eat something hot or cold. 
  • Tooth sensitivity happens when a whitener dehydrates and inflames the living tissue inside a tooth.

Some ways to reduce tooth sensitivity include using anti-sensitivity toothpaste or non-steroidal anti-inflammatory medications to reduce inflammation. 

3. Throat Irritation

You can accidentally swallow carbamide peroxide gel while whitening. This is especially true if you use the product overnight. 

Throat contact can lead to irritation. However, because the product is usually in contact with the throat briefly, this side effect should pass quickly.

4. Uneven Whitening

Uneven whitening is more common with high peroxide concentrations. This effect usually diminishes after a few uses.

How to Choose Carbamide Peroxide Products

You must consider a few factors before choosing tooth whitening products with carbamide peroxide. Here are some of them:


The concentration of carbamide peroxide in your teeth whitening product can determine its safety and effectiveness. As mentioned, 16% and 35% can bleach discolored vital teeth.1 

Delivery Method

Delivery methods vary among carbamide peroxide products. If you choose a teeth whitening product, it’s best to choose the one you can commit to.

For instance, teeth-whitening gels and pens are easier to use than trays. You’re more likely to use these products regularly to achieve your desired results. 


People prone to gum or tooth sensitivity should choose desensitizing products. These products can help whiten teeth without increasing sensitivity. 

Consult a Dentist

Still, the best way to choose a carbamide peroxide is through a consultation with a dentist. They can provide recommendations based on your needs and preferences. Professionals like dentists can also monitor your results to ensure you are safely whitening your teeth.

What Causes Tooth Discoloration and Stains?

A person’s teeth can become yellow or discolored for various reasons. Yellowing teeth is a natural part of aging. As tooth enamel wears down, the yellow layer below (dentin) becomes more visible.

Other types of stains occur on the surface of your tooth enamel. Surface stains are usually the result of tobacco use and staining foods and beverages like red wine and coffee.

You can prevent tooth discoloration by:

  • Keeping up with good oral health by brushing and flossing regularly
  • Limiting staining foods and beverages like coffee, tea, or wine
  • Quitting smoking and tobacco use
  • Maintaining a balanced diet by consuming a diet with fruits and vegetables


Carbamide peroxide and hydrogen peroxide are common ingredients in teeth-whitening products.

Carbamide peroxide is similar to hydrogen peroxide because they’re both oxidizing agents. They produce the same results as whitening treatments. However, hydrogen peroxide breaks down much faster than carbamide peroxide. 

Both are safe to use as in-office and at-home whitening treatments. Talk to your dentist before trying tooth whitening at home.

Last updated on February 1, 2024
6 Sources Cited
Last updated on February 1, 2024
All NewMouth content is medically reviewed and fact-checked by a licensed dentist or orthodontist to ensure the information is factual, current, and relevant.

We have strict sourcing guidelines and only cite from current scientific research, such as scholarly articles, dentistry textbooks, government agencies, and medical journals. This also includes information provided by the American Dental Association (ADA), the American Association of Orthodontics (AAO), and the American Academy of Pediatrics (AAP).
linkedin facebook pinterest youtube rss twitter instagram facebook-blank rss-blank linkedin-blank pinterest youtube twitter instagram