Do Teeth-Whitening Strips Actually Work?

According to the American Dental Association (ADA),¹ whitening strips effectively whiten teeth. Whitening strips cover the teeth in a bleaching gel containing hydrogen peroxide or carbamide peroxide. 

Whitening strips remove surface stains on tooth enamel (outer layer), making them appear brighter. They can improve tooth color by a shade or two in just a few days.⁶ 

Although whitening strips aren’t as effective as in-office whitening techniques, they can be a cost-effective at-home alternative.

Are Whitening Strips Safe?

None of the listed ingredients for whitening strips have been shown to be unhealthy or dangerous. Most whitening strips have a hydrogen peroxide percentage of 9.5%, making them perfectly safe.

When used correctly, most whitening strips are a safe way to whiten teeth.^{1, 2, 3} However, there are a few potential side effects.

Side Effects of Whitening Strips

If you use whitening strips more frequently or longer than recommended, you risk damaging your tooth enamel and gum tissue. 

Other potential side effects of whitening strips include:

• Yellow or gray spots — If the strips aren’t properly applied, uneven whitening results can occur
• Allergic reactions — Although rare, you can experience an allergic reaction if you’re allergic to adhesives
• Tooth sensitivity — If your enamel gets stripped away, it can expose the dentin of your teeth, causing sensitivity in high or low temperatures
• Gum tissue damage — Frequent use can irritate or damage the soft tissue of your gums
• Oral microbiome disruption — The peroxide in whitening gel kills bacterial; if too many bacteria are killed, it can disrupt oral health

Who Shouldn't Use Whitening Strips?

Although whitening strips are relatively safe, they still contain chemicals that can be dangerous in large quantities. This is why there’s a warning on whitening strips that no one under 12 should use the products.

You may also want to avoid using whitening strips if you have damaged gums or sensitive enamel. The chemicals in whitening strips can further damage your mouth if misused.

What are the Ingredients in Whitening Strips?

The following ingredients are common in tooth whitening strips:

Polyethylene

Most whitening strips are made of polyethylene. It’s one of the most common plastics in the world. Because of its lightweight, flexible, and non-toxic structure, it’s ideal for the base of a whitening strip.

Hydrogen or Carbamide Peroxide

These are the main active ingredients in whitening strips. They are natural and safe bleaching agents.²

PVP (Polyvinylpyrrolidone) and Carbomer

PVP and carbomer are adhesive agents. They help whitening strips bind to your teeth. Both of these chemicals are safe and non-toxic. However, if overused, they can cause gum irritation.

Water

Water is included in the gel to prevent carbomer from dehydrating your teeth.

PEG (Polymerization Ethylene Glycol)

PEGs are humectants. These are thickeners commonly used in cosmetic products. The PEG acts to thicken the gel and make it sticky.

Glycerin

Glycerin is a sweet, non-toxic compound. It acts as a humectant to thicken the gel and help the strips stay in place.

Acrylates Copolymer

Acrylates copolymer is another common ingredient in cosmetic products, including whitening strips. It binds the gel and keeps the strips in one piece.

Sodium Hydroxide

Sodium hydroxide is also known as lye or caustic soda. It’s commonly used in whitening strips to adjust the pH to neutral.

Sodium Saccharin

Sodium saccharin is an artificial sweetener used to improve the taste.

How to Use Whitening Strips

Most whitening strips require the same basic steps. However, they do vary from product to product. Read and follow the instructions exactly to ensure safe and effective whitening results. 

Here are the basic instructions for applying at-home whitening strips:

1. Remove the upper and lower strip from the package
2. If necessary, use clean scissors to cut the strips to match the exact height of your teeth
3. Remove the thin layer of plastic covering the adhesive
4. Gently place each strip on your teeth
5. Cover your teeth, but don’t let the strips touch your gums
6. Leave the strips on your teeth for the exact number of minutes listed on the box
7. Remove the strips
8. Rinse your teeth immediately with water
9. Don’t brush your teeth for at least two hours afterward
10. Repeat according to the directions on the box

Your teeth should be clean before you apply whitening strips. However, don’t brush your teeth for at least 30 minutes before using them. Doing so can increase gum irritation.

What Stains Can or Can’t Whitening Strips Remove?

Whitening strips can remove stains. However, this can depend on the type of stain.

The type of stains that they can remove are caused by:

• Age — Teeth naturally get yellower and darker; whitening strips can brighten stains caused by aging
• External discoloration — These are stains caused by foods, drinks, and even smoking

The type of stain whitening strips can’t remove is internal discoloration. Because these stains originate inside your teeth, whitening them can be difficult. Getting your teeth whitened at a dentist is the most effective way to whiten teeth stained by internal discoloration. 

What are the Best Whitening Strip Products?

Crest whitening strips are one of the best whitening strips available today. These dental whitening kits can show visible results within 24 hours. They even offer a great alternative for people with sensitive teeth and gums.

These Crest whitening strips include:

• Crest 3D Whitestrips Glamorous White
• Crest 3D Whitestrips Sensitive

These strips mold to the shape of your teeth, which helps prevent slipping. They are also easy to use and don’t stop you from talking, drinking, or working.

Both are ADA-approved, meaning they’re safe and effective when used properly. Each kit contains 14 to 16 full whitening treatments, with one upper and one lower strip.

Alternative Options 

While whitening strips are an effective treatment option, there are many ways to whiten your teeth. 

Other whitening treatment alternatives include:

• Whitening toothpaste and mouthwash — Can potentially remove or reduce external stains, but they have little to no whitening effect on your teeth.^7,8
• At-home LED whitening kits — Uses an LED light to reduce treatment time and tooth sensitivity. LED teeth whitening produces similar results as whitening strips.^{3, 10, 11, 12, 13} 
• Professional, in-office whitening — A safe and effective way of whitening your teeth. However, it costs more than the other alternatives.

Reasons Why You Should Whiten Your Teeth

Your smile is one of the first things people notice about you. A good smile can leave a lasting impression.

Teeth whitening can brighten up your smile and improve your teeth’s appearance. Other benefits of teeth whitening include:

• Looking younger
• Improving your confidence
• Removing stains from damaged teeth
• Removing external stains 

Whitening strips can be beneficial for at-home use due to their availability. Whitening strips are fast, effective, and cheap.

Summary

Whitening strips are a cheap, effective, and easy-to-use option for at-home teeth whitening. They are generally safe, especially if they have the ADA Seal of Acceptance (e.g., Crest).

Although whitening strips can effectively remove external stains, they can’t remove internal stains. Professional teeth whitening is the most effective option, but treatment costs more.

If misused, teeth whitening strips can damage your teeth and gums. Overuse or misuse of at-home teeth whitening products can result in:

• Gum damage
• Sensitive teeth
• Disruption of your oral microbiome