Does Saliva Ruin Teeth Whitening?

Written & Reviewed by Dr David Chen

Saliva is the arch nemesis of teeth whitening. The presence of saliva can decrease the efficacy and impede the entire bleaching process. In fact, one of the major determining factors for why one whitening product works better than another is in its ability to ward off saliva.

KoR night 16% carbamide peroxide

Of course the winner of that goes to in-office whitening at your dentist because they have a saliva suction. That one simple piece of equipment can make all the difference in the world for how much whiter your teeth can get.

Now without further ado, let’s go over all the reasons why your spit is not good for whitening.

Saliva contains enzymes

Saliva is toxic to peroxide based products because it naturally contains salivary peroxidases. These enzymes will break down hydrogen peroxide when it comes into contact with them.

That is bad news for teeth whitening products because the vast majority of them all use peroxide as their primary whitening agent. Essentially what happens while you’re whitening your teeth is that you start salivating. The pooling saliva which is full of enzymes will then start to inactivate the bleaching gel.

The ultimate result is that your bleaching treatment becomes less effective simply due to the presence of saliva. A lot of the peroxide gets deactivated from the constant pooling of spit.

Does our body not like white teeth?

The reason our saliva has salivary peroxidases has nothing to do with our body’s like or dislike for the color of our teeth. The enzymes are there as a protective mechanism against oxygen toxicity.

A lot of bacteria in the mouth will deliberately produce peroxide as a byproduct. In order to prevent our body from becoming intoxicated with peroxide, we’ve developed a defensive mechanism. The protection happened to come in the form of salivary peroxidases which degrade the peroxide.

It’s purely coincidental that hydrogen peroxide also happens to be a tooth bleaching agent. Perhaps if we discover some other ingredient which can also bleach our teeth, saliva would be less of an impediment.

It can wash away whitening gel

One of the primary functions of saliva is to wash away food and debris from the teeth and gums. That is crucial for keeping our mouth healthy by decreasing the incidence of decay and gum disease. It is a natural protective mechanism.

Unfortunately that is detrimental to teeth whitening because along with the food, it can also wash away the peroxide gel. The saliva does not make a distinction between the different materials on our enamel. It simply tries to cleanse the tooth surfaces of everything that tries to attach to it.

That is not good for our whitening treatment because in order for it to work, the gel needs to stay in contact with our enamel. If the saliva washes it away then it won’t be able to work on the teeth.

Interfere with whitening products

The saliva can also interfere with some whitening products such as the strips. All of that liquid can displace the whitening strips that are supposed to adhere onto the teeth. What you’ll find happening a lot of times is the strips slipping off of the teeth due to saliva.

You can find the same thing happening in the whitening mouthwashes as well because when you’re swishing around, the saliva competes with the mouthwash. You start salivating more as you swish and that dilutes the solution. That means what contacts your teeth may not always be peroxide.

In-office whitening can minimize saliva contact

It is impossible to eliminate saliva completely from your mouth but in-office treatments can minimize it. Your dentist has a nifty little piece of equipment called the saliva ejector.

saliva ejector

It is literally a little plastic tube that looks like a straw but it can suck the saliva straight out of your mouth. The pediatric dentists like to call it “Mr. Thirsty” since it likes to drink saliva.

The saliva suction is one of the reasons why whitening at the dentist is so much more efficacious than DIY at home products. Whatever you use at home will never be able to minimize the amount of saliva pooling in your mouth.

The simple act of sucking up saliva and preventing it from coming into contact with the peroxide gel makes all the difference in the world!

Can you stop salivating at home?

You should know that as soon as you put something in your mouth you will start salivating. It is a natural bodily reflex that occurs each and every time without fail. Since teeth whitening requires putting gel and other objects into your mouth, your mouth will start pooling spit within a few minutes.

Of course it would be advantageous for you if you could stop the saliva because then your treatment can be more efficacious. We’ve come up with three ways on how to minimize the amount of saliva in your mouth during treatment at home.

  • Lay in bed and swallow the saliva. If you whiten while laying in bed, you can swallow your saliva as soon as it starts to pool. This will prevent it from coming into contact with the peroxide gel.
  • Choose an overnight product. We actually tend to salivate less once we are asleep. If you use an overnight whitening product like one of the teeth whitening pens, it may be more effective. Once you fall asleep, the amount of saliva should start to slow down.
  • Gently spit out. Alternatively you can also spit out the saliva while you’re whitening as it starts to pool. Just remember to do it gently so it doesn’t disturb the gel that is on your teeth. If you have the strips on you also don’t want to spit out the strips by accident.


Saliva can decrease the efficacy of your whitening as well as impede it. It is certainly no friend in getting your teeth whiter. In fact, if you had a dry mouth and never salivated anymore, you would probably get better whitening results.

Essentially our saliva contains enzymes which can break down the whitening gel. In addition to that its presence will also wash away the gel as well as interfere with the various bleaching products.

Due to all of these reasons above, we consider saliva to be the mortal enemy of teeth whitening. Yes, that means it can ruin your entire treatment if you don’t control the saliva.


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