Does Swishing With Hydrogen Peroxide Whiten Your Teeth?

Hand written by Dr David Chen, an actively practicing dentist and avid writer. #doctorswrite

Simply browsing through the hundreds of different OTC whitening products will quickly reveal a common denominator among them. All of these bleaching products contain hydrogen peroxide which is the primary teeth whitening agent.

swan hydrogen peroxide

As you may astutely noticed, that little brown bottle of antiseptic mouth rinse also has hydrogen peroxide, albeit at a lower 3%. In fact you may even have a bottle in your medicine cabinet as we speak.

You probably bought it to disinfect skin wounds and occasionally rinsed your mouth with it if you had gum swelling. You’ve never intended for it to be used as a whitening mouthwash but can it whiten your teeth? After all, all of the whitening products which you’ve seen online and in stores all contain it

Whitening mouthwashes do contain hydrogen peroxide

Perhaps you may not have been aware of it but there are mouthwashes out there specifically meant for whitening your teeth. These whitening mouthwashes all contain varying concentrations of hydrogen peroxide (HP) and that is how they make your teeth less yellow.

optic white mouthwash 2% hydrogen peroxide

Examples of whitening mouth rinses that are peroxide based:

Both of these mouthwashes are marketed as being able to whiten your teeth. They both contain peroxide with the Colgate having 2% while the Crest does not disclose the concentration.

How to swish with hydrogen peroxide to whiten teeth

  1. Pour 15 mL into cap.
  2. Swish and gargle for 60 seconds.
  3. Spit back out and do not swallow.

You can basically repeat the steps above twice a day for whiter teeth. You also must be 12 years or older to use this product as per Colgate.

Whitening mouthwash vs Hydrogen peroxide in a brown bottle

If you were wondering if there was a difference between the “whitening mouthwashes” and the typical brown bottle of hydrogen peroxide, there isn’t one. Peroxide is peroxide and nothing in the world will make it different. In other words, the peroxide in both types of mouth rinses should have identical effects.

However we do want to point out that the brown bottle of HP actually contains a higher percentage of peroxide than whitening mouth rinses that are commercially available.

What makes it even more interesting is that the brown bottle of peroxide does not list teeth whitening as one of its uses on the label. Although it does possess the ability to brighten them.

First aid to help prevent the risk of infection in minor cuts, scrapes and burns – aids in the removal of phlegm, mucus, or other secretions associated with occasional sore mouth

Dailymed NIH

Isn’t it absolutely fascinating that the more potent everyday product that is not listed as a bleaching product should be more effective than the actual whitening rinses?

Can a mouthwash with hydrogen peroxide whiten teeth?

As long as the product contains hydrogen peroxide, it will have a teeth whitening effect. Mouth rinses which contain HP will be able to make your teeth whiter because the mechanism for how it whitens remains the same.

Hydrogen peroxide is a powerful oxidizer of tooth stains because it can diffuse through the tooth while oxidizing intrinsic as well as extrinsic stains. That means it can bleach both types of teeth stains.

To go a little bit deeper in how that results in whiter teeth… it isn’t the peroxide that directly bleaches your teeth. HP is actually very unstable and will naturally degrade into water, oxygen, and heat. However there are intermediary steps which produce free radicals (perhydroxyl) which are the true oxidizing or whitening agent.

hydrogen peroxide decomposition to radicals - reaction equations
Hydrogen peroxide degradation mechanism

The point that we want to make is that as long as the product contains peroxide, it will go through this same mechanism and it will produce the perhydroxyl radical. In other words your teeth will become whiter if you use a mouth rinse with HP.

Peroxide mouth rinse whitening efficacy

Despite us hounding you in the entire article that swishing with hydrogen peroxide can whiten your teeth, unfortunately it is not the most effective way to do it. There are inherent disadvantages to it if you’re trying to bleach them via just swishing and gargling with HP.

Saliva impedes whitening efficacy

Saliva is the arch nemesis to all of teeth whitening because it contains salivary peroxidases. These are enzymes which break down peroxide in order to prevent our body from toxicity. Its purpose is to render hydrogen peroxide to become harmless.

That is actually one reason why in-office whitening at the dentist is so effective because they’re able to isolate your teeth from saliva. If you recall, your dentist has a saliva ejector which suctions out saliva from your mouth. This reduces the amount of saliva in your mouth and helps to prevent it from coming into contact with the whitening gel.

When you whiten at home you often lose this benefit because you don’t have a saliva suction. That in itself makes all at home products less effective than the professional in-office ones.

Last but not least, when you use hydrogen peroxide as a mouthwash and swish around with it you’re purposefully exposing it to saliva. Then there is also the fact that you tend to salivate more while you’re swishing and gargling with it. Due to the combination of all of these factors, it actually decreases the efficacy of whitening mouthwashes in general.

Rinsing duration is insufficient

Another often glazed over factor which renders peroxide mouth rinses less effective for whitening your teeth is the short rinsing duration. Most mouthwashes only require you to rinse for about 60 seconds before spitting it back out. If you were trying to whiten your teeth, that is a super short treatment time is it not?

You can compare it to professional in-office whitening which have you in the chair with the bleaching gel on your teeth for about 60 minutes. It’ll all make sense if we lay it out for you.

Peroxide mouthwash:

  • Whiten for 60 seconds
  • 3% concentration of peroxide
  • No protection against saliva

In-office whitening procedure:

  • Whiten for 60 minutes
  • 35-40% concentration of peroxide
  • Saliva suction present

Essentially what makes this mouth rinse version of HP less effective is that it doesn’t whiten your teeth for a long enough period of time. Studies have shown that lower concentration products can whiten teeth to the same level as higher concentration products but it simply requires a longer treatment time.

The way we use mouthwash goes against what we know about whitening. We should technically be rinsing with it for a longer period of time if we actually want to see results but we don’t. No one really rinses for longer than a minute anyway.


Swishing with hydrogen peroxide will whiten your teeth because it is a legitimate whitening agent. In fact, it is the exact same ingredient that is used in all whitening products from pens to strips and even in-office professional treatments.

However it may not be as effective as you may think because saliva and also the short rinsing time hampers its results. Nonetheless, it is still a great adjunct to your armamentarium of keeping your teeth white. If your goal was to have bright white teeth, of course choosing a whitening mouthwash would be better than a non-whitening one. Therefore there is still a place for HP rinses.


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