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SLS Negatively Affects Fluoride Toothpastes

Sodium lauryl sulfate (SLS) will negatively affect fluoride in toothpastes by reducing its bioavailability, which is counterproductive for cavity prevention.

Charcoal toothpaste with SLS and fluoride - colgate optic white
Charcoal toothpaste with SLS and fluoride

How SLS affects fluoride in toothpaste

Studies have shown that sodium lauryl sulfate in toothpaste will decrease the bioavailability of fluoride by interfering with it's deposition onto the enamel surface.

Mechanism: SLS is a surfactant/detergent which wets the surfaces of the teeth to facilitate removal of debris, food, and plaque.

  • Unfortunately, it indiscriminately removes all substances on the teeth including fluoride which is supposed to stay on your teeth.

  • It literally cleanses away everything, the bad stuff as well as the good stuff.

SLS schema
SLS schema - Credit: Science on the Shelves

What it means: Fluoride toothpastes that contain sodium lauryl sulfate will have a reduced anti-cavity effect when compared to toothpastes without it.

  • The cleansing effect of SLS effectively lowers/reduces/decreases the anti-caries potential of your fluoridated toothpaste.

  • This ingredient does NOT maximize the beneficial effects of fluoride.

The main takeaway is that the surfactants work against the protective effects of fluoride.


What about other toothpaste surfactants?

SLS is the most prevalent surfactant/detergent in oral care products but some toothpastes use different ones such as cocamidopropyl betaine, cocamidopropyl hydroxysultaine, sodium cocoyl glutamate and etc. (We do have a full list of toothpaste ingredients).

These other detergents within toothpaste should theoretically elicit the same negative effect on fluoride as SLS albeit to a lesser degree.

One study found that the cocamidopropyl betaine (CAPD) had better fluoride effects when compared with sodium dodecyl sulfate.

  • We can attribute this difference to the potency of strength of the detergents.

  • SLS is much more potent than the CAPD and thus should be more detrimental to fluoride.

Overall, we would have to say that a milder detergent would be better for maximizing the effect of fluoride. Although a toothpaste without any at all would be the best.


Is SLS bad for toothpaste?

Our dentists in Long Island City are not completely opposed to toothpastes with SLS in them because they do serve a specific purpose such as for teeth whitening.

You need a strong detergent in order to remove stains from your teeth. Without it, you won't be able to whiten as well. Therefore any whitening toothpaste that is worth its salt should have SLS in it. An example would be the colgate optic white advanced toothpaste.

Whitening toothpaste with SLS
Whitening toothpaste with SLS

However, if your main focus is on preventing cavities, you may want to choose one without SLS in order to maximize the anti-caries effect. An example would be the sensodyne pronamel intensive enamel repair which is SLS-free. Although a common complaint that we get with these toothpastes is that they don't quite foam as much.

sensodyne pronamel intensive enamel repair

Ultimately it comes down to what you're looking to get out of your toothpaste!


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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