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Can You Use Crest White Strips While Breastfeeding?

Updated: Dec 20, 2023

It is safe to use Crest whitestrips while breastfeeding if you use it in moderation because breast milk actually contains peroxide in it For your information, the main whitening ingredient in the white strips is peroxide.

crest whitestrips unboxed

Table of Contents:

Pregnancy guidelines

The American College of Obstetricians and Gynecologists (ACOG) has a guideline for elective cosmetic procedures during pregnancy. That includes all forms of teeth whitening such as the crest white strips. You're supposed to postpone all of these elective procedures while you're pregnant and the American Dental Association (ADA) agrees wholeheartedly.

However it is important to note that the guidelines only mentioned postponement while carrying a baby but not afterwards while breastfeeding. Therefore there is no official statement in regards to what you can do while you're nursing.

Common sense dictates that the safest thing to do is to wait until you're no longer breastfeeding.

Breast milk naturally has hydrogen peroxide

Did you know that human breast milk naturally contains hydrogen peroxide (H2O2)? YES, you read that correctly because we'll prove it to you here.

According to a Pediatric Research Study, hydrogen peroxide (HP) is generated by breast tissue xanthine oxidase while oxytocin stimulates milk production.

  • There is an appreciable amount of H2O2 in the milk which peaks a few days post-partum.

  • The amount of H2O2 then steadily declines towards the fourth week.

mechanism for hydrogen peroxide generation in human milk
Credit: Monika Cieslak, Cristina H F Ferreira, Yulia Shifrin, Jingyi Pan & Jaques Belik

In other words, during the first week that you're breastfeeding, the milk contains an appreciable amount of hydrogen peroxide. The highest amount of H2O2 is found in the first week post-partum but then declines with each subsequent week.

For additional validation, a different study also found similar results. Now you're probably wondering, why in the world is there peroxide in your breast milk?!

Relationship between hydrogen peroxide and crest whitestrips

The main whitening ingredient which makes your teeth whiter in crest white strips is hydrogen peroxide. All of the other ingredients don't bleach your teeth but they are there to assist the peroxide in working more effectively.

Crest white strip list of ingredients:

  • Water - prevents carbomer from desiccating the teeth

  • Glycerin - humectant

  • Hydrogen peroxide - whitening ingredient that bleaches your teeth

  • Carbomer - makes the gel sticky

  • PVP (Polyvinylpyrrolidone) - adhesive for the strip

  • PEG - humectant/thickener

  • Acrylates copolymer - thickener

  • Sodium hydroxide - adjusts pH to neutral

  • Sodium saccharin - flavoring

  • Pyrophosphates - tartar control agent

  • Polyethylene and Polypropylene - what the strips are made of.

Out of all of those ingredients, the only whitening agent is hydrogen peroxide. It whitens your teeth by forming free radicals that can diffuse through the enamel and dentin while oxidizing stains. That is essentially the mechanism for how all teeth whitening products bleach your teeth.

What all of this means is that your body is naturally producing teeth whitening ingredients and you're breastfeeding it to your baby. That may sound absolutely bizarre but it all makes sense if you understand why there is H2O2 in it.

Why does breast milk contain peroxide?

Whitening your teeth is simply one function of hydrogen peroxide because it can do much more than that. Don't forget that peroxide is also used as an antiseptic and you can commonly find it in little brown bottles at the pharmacy. Yes, they are the exact same peroxide!

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

Essentially the purpose for peroxide within breast milk is to disinfect it so that your baby can drink it bacteria free. Your body produces it because of its antimicrobial properties and it provides significant protection against infections. Studies have shown that infants who are breastfed typically experience fewer and shorter bouts of infections.

That actually goes to show that having peroxide in the milk is a good thing and it is intentional. Although it seems like this protective effect is needed more during the first week of being born. Its effect seems to decrease with each passing week which probably implies that the baby's immune system takes over after that.

Isn't this one of the most amazing things that you've learned today?

Reasons crest white strips are safe while nursing

According to the lactation database by LactMed, there is no reason to discontinue breastfeeding if peroxide is being used as directed. They say that it is unlikely for carbamide peroxide which is found in ear drops or teeth whiteners to get absorbed into the bloodstream.

Even if it did, it would simply break down into urea and hydrogen peroxide which is normally found in breast milk. Due to these reasons, LactMed states there are no special precautions required when using carbamide peroxide.

Credit: Aina N. Gadanha, Charline R. Rossini, João P. S. Fernandes & Márcio Ferrarini

Carbamide peroxide is a precursor to hydrogen peroxide. Since it has to first break down into hydrogen peroxide, that extra step actually makes it more shelf-stable. You can think of it as an extended release formula for HP.

The vast majority of teeth whitening products will either contain carbamide peroxide or hydrogen peroxide. The crest whitestrips in particular contain the latter. The take home professional whitening kit which we give to our patients contains former.

kor 16% carbamide peroxide whitening gel

To sum it up, it is most likely safe to be using whitening strips while you're still nursing. In addition to what LactMed has said, our body rapidly detoxifies peroxide and our saliva contains salivary peroxidases. Both of these are defense mechanisms to prevent peroxide toxicity. Last but not least, the concentration of peroxide is on the lower end for the strips.

Peroxide gets rapidly detoxified

Studies have shown that hydrogen peroxide gets rapidly metabolized prior to even reaching the bloodstream. Therefore use of whitening products is not likely to be a concern. However they did say that is only the case if it is done in moderation. Basically this study lends support to what LactMed is stating.

Salivary peroxidases

Our saliva naturally contains salivary peroxidases which are enzymes that break down hydrogen peroxide. It is actually meant to protect our mouth against bacteria which produce it.

However since whitening strips also use HP, our saliva will naturally inactivate it. Yes, our saliva is the arch nemesis for all teeth whitening products because they render it ineffective if you leave it in contact with one another. Therefore, your mouth naturally detoxifies the crest white strips even if you don't ask it to!

Low concentration

The peroxide concentration in the strips is much lower than any professional product that you'll ever use. Crest doesn't list what the potency is on their website but according to studies, the retail version of it comes in 6.5% hydrogen peroxide. That is significantly less than the 40% in-office treatment by Opalescence Boost.

40% peroxide opalesence boost

Of course the less potent the product, the less chances that it can cause you harm. The more potent it is, the greater the possibility of causing you harm if something goes wrong.

Reasons why crest white strips could be harmful

Despite all of the evidence above which leans towards the crest whitening strips to be probably safe for use during nursing, there is still a risk. The risk lies in the fact that there haven't been a lot of studies done on women who are breastfeeding and using peroxide.

Therefore we don't truly know the actual effects and results. Most of the evidence is just based on what we know about how the materials react with one another. To be truly sure, a robust study would need to be conducted.

However, as with all things related to pregnancy, society is not very keen on experimenting on expecting mothers or mothers with newborns. It just seems a bit unethical if you know what we mean.

Last but not least, whitening can still be harmful when it is misused and abused. Excessive whitening can lead to adverse effects and that occurs regardless of if you're nursing or not. Studies have shown that people who are bleachorexic can end up with spontaneous bleeding gums and sloughing of the mouth.

So can you use crest white strips while breastfeeding?

Based on all of the evidence that we've found above, it is most likely safe to use crest white strips while you're breastfeeding as long as you do it in moderation.

crest whitestrip packet

OTC products in general come in a lower concentration of hydrogen peroxide and that is on purpose. It is done to prevent people from trying to misuse the product since there is no dentist supervision.

Then there is also the fact that breast milk naturally contains peroxide in it. It's not used to whiten your infant's teeth since they don't have any teeth at that age but it is to prevent infections. The peroxide helps to disinfect the milk via its antimicrobial properties.

If you're nursing, you're practically feeding your baby hydrogen peroxide! Nonetheless, you still shouldn't worry too much because according to LactMed, the whitening material typically doesn't get absorbed into the bloodstream anyway.

However we do want to leave you with a warning and that is only if you use these products in moderation. It also only applies to the crest white strips since it is safer due to its lower concentration. If you overdo it with professional products something bad can certainly happen.

Does this also apply to other brands of whitening strips?

Other brands of whitening strips are not much different from the crest ones. They all use the same ingredient to bleach your teeth which is peroxide. It's just that they may add different flavorings and other non-whitening ingredients to the mix. Therefore it should largely function the same way.



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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