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Is Hydrogen Peroxide Safe For Use On Teeth?

When used as directed, hydrogen peroxide is safe to use on your teeth during whitening and also as a mouthwash. Teeth sensitive may occur but symptoms are typically mild and transient if directions are properly followed.

hydrogen peroxide

However when it's used improperly there can be an increase in adverse effects such as teeth sensitivity, demineralization, and pulp toxicity. Therefore it is imperative that you read the instructions on the product label carefully and follow them to the T. That way you can minimize most of the side effects.

Table of Contents:

Potential side effects from using hydrogen peroxide

Hydrogen peroxide (HP) is an acid, a mild antiseptic, and a potent oxidizing agent for tooth stains. Despite all of these wonderful benefits which may be derived from its use, it is not free of side effects.

These adverse effects are usually mild but overuse and abuse of this solution can cause the symptoms to become more severe. That can result in pain, tenderness, and sensitivity.

Burning sensation

Since it is an acidic agent, when it comes into contact with the oral mucosa or the skin it may elicit a burning sensation. This is why it'll feel very similar to rinsing with an alcohol based mouthwash. You'll feel the inside of your mouth tingling as you rinse and swish with it.

Similarly if you use HP as an antiseptic on wound, it will sting as soon as it touches it. Once again it is very similar to how rubbing alcohol burns when applied to a small cut.

Teeth sensitivity

One of the most prominent side effects of whitening your teeth is sensitivity. There is a plethora of studies which have demonstrated this adverse effects that it has now become irrefutable.

This randomized clinical study compared at home vs in-office treatments as well as varying concentrations of hydrogen peroxide. The results were that ALL types of treatments resulted in sensitivity afterwards. There were no exceptions to the rule.

However the good news was that during follow up visits, all of the symptoms went away. That means this side effect is only present during treatment but subsides on its own, meaning that its transient in nature.

Gum inflammation

Another notable side effect is gum inflammation while whitening your smile. This often occurs as the result of the bleaching gel spilling over and coming into contact with your gums.

Hydrogen peroxide will not only bleach your teeth but the gums as well. During mild cases, the gums will turn white and feel tender.

white gums after teeth whitening
white gums after teeth whitening

However for moderate-severe cases such as when teeth bleaching goes wrong, the gums can be burned black. This often happens during improper use of the products or getting the treatment done by non-licensed clinics such as kiosks at the mall.

If you do happen to have burned gums from whitening, there are ways to treat it. Although most of it is palliative in nature and not really a cure. Nevertheless, it will ease the discomfort and make the healing process more pleasant.


An often glossed over side effect, teeth do demineralize when they are being whitened. Demineralization is when the enamel loses minerals because the acidity from the hydrogen peroxide pulls calcium and phosphates out of the tooth. After all, the peroxide is acidic.

demineralization remineralization of teeth
Credit: Sangi Co

However the good news is that the teeth can undergo remineralization when you brush with a remineralizing toothpaste. For instance, fluoride and nano-hydroxyapatite toothpastes possess these capabilities. Brushing with these will repair the tooth by adding minerals back into the enamel. In addition to the dentifrices, there are other things you can do to help successfully remineralize teeth.

Pulp toxicity

Hydrogen peroxide has been shown to be toxic to the tooth pulp but the nerve usually does spontaneously recover all on its own. A study by the Journal of Dentistry, tested varying concentrations of peroxide and their toxicity on the pulp.

  • There was only one instance of pulp toxicity that did not recover and that was from using 35% HP for three 15 minute sessions.

  • The rest of the concentrations and treatment lengths did not cause irreversible damage.

Their overall recommendation was to reduce the 35% concentration to make it safer. However, they also stated that you can also reduce the contact time of the 35% by 5 minutes and that would eliminate the irreversible damage.

To summarize, a higher concentration of HP can still be used safely if you reduce the amount of treatment time. A lower concentration of HP can be used safely for a much longer period of treatment time. Most of the symptoms will recover on their own.

Bleeding and sloughing of soft tissue

Under normal circumstances, whitening will not cause bleeding or sloughing of the oral mucosa when used as directed. However for bleachorexic patients who are addicted to bleaching their teeth, overuse may result in these symptoms.

There was a case report which documented these symptoms in a 55 year old female who was a whitening junky. The good news was that after she was advised to stop her twice daily whitening, all of the symptoms resolved after two weeks.

Is it safe to use?

When used as directed and all of the instructions are followed closely, hydrogen peroxide is relatively safe for teeth. We will explain all of the reasons as to what makes it not harmful.

If you needed reassurance look no further than what the Public Health of England has to say about it. It is technically safe to use even during pregnancy because it gets rapidly detoxified and very little of it gets absorbed. Therefore it is not likely to cause harm to the unborn child.

Swallowing saliva is not harmful

One concern that many people have while whitening their teeth at home is in regards to swallowing during treatment. An example would be swallowing while using crest white strips.

According to Crest, it isn't harmful to accidentally swallow saliva that may have some peroxide in it while you're whitening. The reasoning is that our saliva naturally contains salivary peroxidase which are enzymes that degrade HP.

crest whitestrips
crest whitestrips

That means the peroxide gel gets actively detoxified when it comes into contact with our saliva. It is a protective mechanism to protect out body from becoming toxified. Unfortunately that also makes saliva the enemy of all teeth whitening since it inactivates it!

Nonetheless, the end result is that whatever liquid that you're swallowing is probably no longer potent.

Manufacturers have already determined optimal concentration to usage time

According to the pulp toxicity study above, HP can be toxic at high concentrations when used for an extended duration of time. However if you decrease the concentration or shorten the treatment time, it makes it safer.

The point we want to make is that the concentration of the product and the specified whitening times are considered safe. The manufacturers have done their research and have determined that is the optimal way to use their product.

That means as long as you follow the directions, it should be safe to use on your teeth. What that also implies is that if the whitening strips says to use for 30 minutes, you shouldn't leave them on your teeth for 2 hours. That is the only time it may be hazardous!

Symptoms are mostly transient

The two most common symptoms from whitening with peroxide are sensitivity and gum inflammation. However discomforting they may be, they will subside all on their own. According to the American Dental Association, the symptoms should resolve after about four days.

However if it is a little too much for you to bear, we do have a guide on how to stop sensitive teeth pain immediately. No reason for you to suffer through it when there are ways to alleviate the discomfort.

Highly concentrated or large quantities can be harmful

Highly concentrated hydrogen peroxide or large quantities of low concentration of it can be dangerous when ingested. This was demonstrated via multiple case studies in a European Union Risk Assessment Report.

One case had a 2 year old boy who ingested 4-6 oz of 35% HP. The boy became rapidly unresponsive and passed away four days later.

Another case was of a 16 month old boy who was playing with a bottle of 3% HP and consumed about 230g of it. He started foaming at the mouth and passed away 10 hours later.

That just goes to show that while it is safe most of the time, it can be lethal when used improperly. Yes, both of these cases were of children so it is more toxic to them. However that doesn't mean that as an adult you can't get some very bad adverse effects.

Safety differences for peroxide in whitening vs mouthwash

Both of them use the same exact ingredient which is peroxide. The only difference between them is that the mouthwash tends to be of a lower concentration, usually about 2%. The whitening products can be as high as 40% for in-office whitening treatments.

optic white mouthwash

Due to the differences in concentration, the mouthwash will always be significantly safer than the other bleaching products. Although if you were to drink the mouth rinse, you can certainly cause lethal harm as shown in the case reports above. Thus, you still need to be careful and make sure you do not swallow any while you're rinsing.


Hydrogen peroxide is safe for use on teeth as long as you use it as directed and follow the instructions closely. If it wasn't safe, it wouldn't be be available commercially. However if you abuse the product or overuse it, bad things can happen. The symptoms can range from mildly discomforting to even death.

Therefore according to our dentists in Long Island City, you can use peroxide on your teeth safely for teeth whitening purposes.


David Chen 200 x 200.jpg

About the author: Dr David Chen, DDS

Hello, I'm Dr Chen and I'm an actively practicing dentist in Long Island City, NY. I graduated from Columbia University College of Dental Medicine in 2016 but prior to going to dental school I was already working in the dental field. It's been more than a decade since I first got to know dentistry and let me tell you, time flies by quickly. Since then I've developed a fondness for writing, which is how this all got started!

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Medical Disclaimer:

This blog is purely meant for information purposes and should not be used as medical advice. Each situation in your mouth is unique and complex. It is not possible to give advice nor diagnose any oral conditions based on text nor virtual consultations. The best thing to do is to go in person to see your dentist for an examination and consultation so that you can receive the best care possible.

The purpose of all of this oral health information is to encourage you to see your dentist and to inform you of what you may expect during your visit. Due to the unfortunate nature of dentistry, there isn't really any true home remedies that will get rid of dental problems. Roughly 99.99% of them require in-person intervention by a healthcare professional.

Hint: That is the reason why you can't eliminate seeing dentists in your life!

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