Is SLS Bad in Toothpaste? A Dentist Explains

While sodium lauryl sulfate (SLS) is not inherently "bad" in toothpaste, many people experience adverse reactions to it, such as oral irritation, allergic reactions, and canker sores.

In the past, SLS has been a common toothpaste ingredient that helped remove debris and stains from the teeth due to its detergent properties. However, due the potential negative long-term effects of SLS on oral health, SLS free toothpastes have emerged as a safe and gentle substitute for it.

In this article, I'll explain everything you need to know about SLS and whether or not it's bad in toothpaste.

What is sodium lauryl sulfate?

SLS in Toothpaste

Sodium lauryl sulfate, also known as SLS, is a detergent, surfactant compound, and foaming agent found in many household cleaning products and personal care products, including:

  • toothpaste

  • shampoo

  • shaving cream

  • and body wash.

Its primary function is to create foam and lather, which helps to remove dirt, oil, and debris from the surface being cleaned. Sodium lauryl sulphate is commonly found along side of similar ingredients such as hydrogen lauryl sulfate.

In toothpaste, SLS helps your toothpaste disperse evenly throughout the mouth and reach areas that may be difficult to access. However, SLS can also be quite harsh as it has the potential to strip away oral mucosa, the protective layer of saliva that coats the gums and oral tissues.

This can lead to dryness and irritation in the oral cavity, especially for individuals with sensitive gums or a predisposition to oral sensitivity. For this reason, many people are turning to SLS free toothpastes for a safer, more gentle clean.

Why does SLS do in toothpaste?

SLS in Toothpaste

SLS is commonly included in toothpaste for its surfactant properties, which help create foam and lather. This foaming action helps you distribute toothpaste throughout your mouth during brushing which allows it to reach areas that might otherwise be difficult to access.

Additionally, SLS enhances the cleaning efficacy of toothpaste by effectively removing debris, food particles, and plaque from the teeth and gums.

While toothpaste is generally safe and SLS can be beneficial in toothpaste, some people may experience allergic reactions or increased sensitivity to SLS, manifesting as recurrent aphthous ulcers, canker sores, or a burning sensation in the mouth. Therefore, there is ongoing debate and research regarding its potential adverse effects on oral health.

Thankfully, as technology has progressed, we now have newer, more gentle surfactants that can be found in SLS free toothpastes as compared to SLS containing toothpaste.

Risks of SLS in Toothpaste

A man showing his teeth

The risks associated with sodium lauryl sulfate (SLS) in toothpaste primarily revolve around its potential to cause irritation and sensitivity in some individuals. SLS is a surfactant that can strip away the protective layer of saliva on the gums, leading to dryness and irritation.

Some people may experience allergic reactions or increased sensitivity to SLS, manifesting as mouth ulcers, canker sores, or a burning sensation in the mouth.

Let's walk through some of the main risks of SLS toothpaste.

Oral Irritation

Oral irritation is a common concern associated with sodium lauryl sulfate (SLS) in toothpaste. SLS is a surfactant, which means it has detergent-like properties that allow it to create foam and facilitate the distribution of toothpaste ingredients. However, these same properties can also strip away the protective layer of saliva on the gums, leading to dryness and irritation.

Furthermore, SLS can disrupt the delicate balance of your oral biome, potentially contributing to oral health issues such as gum inflammation or infection. This disruption of the oral microbiome, coupled with the abrasive nature of SLS, can exacerbate oral irritation and discomfort.

Dry Mouth

Dry Mouth

Dry mouth, or xerostomia, can be a potential risk associated with sodium lauryl sulfate in toothpaste.

SLS is a surfactant that creates foam and aids in the distribution of toothpaste ingredients, but it can also strip away the protective layer of saliva in the mouth. Saliva plays a crucial role in maintaining oral health by lubricating the oral tissues, buffering acids, and washing away food particles and bacteria. When SLS disrupts this protective saliva layer, it can lead to dry mouth.

For individuals already predisposed to dry mouth, such as those taking medications that reduce saliva production or individuals with certain medical conditions, switching to SLS free toothpastes may alleviate discomfort.

Allergic Reactions

Some individuals may experience allergic reactions upon exposure to SLS in toothpaste. These reactions occur when the body's immune system overreacts to the presence of SLS, triggering inflammatory responses throughout the body. For those people with a history of allergic reactions or sensitive skin, switching to fluoride free toothpaste without SLS can reduce risk.

Increased Risk of Aphthous Ulcers

The presence of sodium lauryl sulfate (SLS) in toothpaste has been associated with an increased risk of developing aphthous ulcers, also known as canker sores, for some individuals. Aphthous ulcers are painful sores that can form on the inner lining of the mouth, including the gums, tongue, and inner cheeks. SLS may exacerbate the occurrence or severity of these ulcers due to its potential to disrupt the delicate oral mucosa, leading to tissue irritation and inflammation.

Taste Alteration

SLS is a surfactant that creates the foaming action commonly observed when brushing teeth. However, this surfactant may also interfere with taste receptors in the mouth, leading to a temporary change in taste perception. Some people may report experiencing a bitter or metallic taste after using toothpaste containing SLS, which can linger for a short period following brushing.

Does SLS cause canker sores?

Yes, SLS has been associated with an increase in the frequency and severity of canker sores.

Experts suggest that SLS may potentially contribute to the formation of canker sores by causing irritation or disruption to the delicate tissues inside the mouth. SLS is known to act as a surfactant, which can strip away the protective layer of saliva on the gums, leading to dryness and irritation.

This irritation may create an environment conducive to the development of canker sores, particularly in individuals who are predisposed to oral sensitivities or have a history of recurrent aphthous ulcers.

However, I should note that the evidence linking SLS directly to the onset or exacerbation of canker sores is not definitive, and individual responses to SLS may vary.

Do I need SLS in toothpaste?

No, you do not need SLS in toothpaste. While SLS serves as a foaming agent and helps distribute toothpaste ingredients, its presence is not essential for effective oral hygiene. In fact, many people choose to avoid SLS due to concerns about potential side effects such as oral irritation, dry mouth, or allergic reactions.

Other surfactants found in toothpaste include, but are not limited to, sodium dodecyl sulfate and anionic surfactants derived from coconut oil.

Should I use SLS free toothpaste?

Yes, you should use SLS free toothpaste if you prefer to avoid SLS due to concerns about potential side effects such as oral irritation, dry mouth, or allergic reactions. Opting for SLS-free toothpaste may be beneficial for individuals who experience discomfort or adverse reactions when using products containing SLS.

Summary: What's SLS in toothpaste?

Sodium lauryl sulfate (SLS) is a toothpaste ingredient used to create that lovely, foamy lather that we all know and love. It's a detergent agent that helps to remove debris and stains from the teeth, contributing to the cleaning action of toothpaste.

However, many individuals may be sensitive to SLS, experiencing oral irritation or other adverse reactions. For this reason, SLS is considered by many as an ingredient to avoid in toothpaste.

These negative reactions have led to the rise of SLS free toothpaste as a safe and gentle alternative to SLS-containing toothpastes.

Frequently Asked Questions

Should I avoid SLS in toothpaste?

You might want to avoid sodium lauryl sulfate (SLS) in toothpaste due to concerns about its potential adverse effects on oral health. SLS is a surfactant commonly used in toothpaste to create foam and aid in the distribution of ingredients, but it can strip away the protective layer of saliva on the gums, leading to dryness and irritation. Additionally, SLS has been associated with oral irritation, increased sensitivity, and allergic reactions in some individuals, which can manifest as mouth ulcers, canker sores, or a burning sensation in the mouth.

What does sodium lauryl sulfate do to teeth?

Sodium Lauryl Sulfate (SLS) in toothpaste acts as a surfactant and foaming agent, creating the characteristic lather that aids in the removal of debris and stains from the teeth. It works by lowering the surface tension of water, allowing it to spread more easily and penetrate between teeth for thorough cleaning. Additionally, SLS can help to solubilize other ingredients in toothpaste, ensuring they are evenly distributed throughout the oral cavity during brushing.

Is SLS cancerous?

There is no conclusive evidence to suggest that sodium lauryl sulfate (SLS) causes cancer when used in toothpaste. However, some people have raised concerns about its potential to interact with other compounds and form nitrosamines, which are known carcinogens. While the risk of cancer from SLS in toothpaste is considered low, individuals with specific sensitivities or concerns may choose to opt for SLS-free alternatives to minimize potential risks.

Why is SLS harmful?

Sodium lauryl sulfate (SLS) is considered harmful due to its association with several potential side effects, including oral irritation, dryness, and increased sensitivity. It can strip away the protective layer of saliva on the gums, leading to dryness and irritation, and may exacerbate existing conditions such as canker sores or mouth ulcers. Furthermore, some individuals may experience allergic reactions or heightened sensitivity to SLS, manifesting as burning sensations or itching in the mouth. While SLS is generally regarded as safe for use in toothpaste by regulatory agencies, concerns persist about its potential adverse effects on oral health, particularly for those with sensitivities or pre-existing conditions.

Should you avoid SLS?

Yes, you may want to avoid SLS due to its potential for causing adverse side effects. While SLS is generally considered safe for most people and provides effective cleaning properties, some individuals may experience oral irritation or sensitivity to this ingredient. If you have a history of adverse reactions to SLS or prefer to use products with gentler formulations, opting for SLS-free toothpaste may be a suitable choice.


NOBS Toothpaste Tablets
NOBS Toothpaste Tablets
NOBS Toothpaste Tablets
NOBS Toothpaste Tablets
NOBS Toothpaste Tablets
NOBS Toothpaste Tablets
NOBS Toothpaste Tablets
NOBS Toothpaste Tablets
NOBS Toothpaste Tablets

NOBS Toothpaste Tablets

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NOBS is everything toothpaste should be - all the good stuff, and none of the junk.

Fluoride Free
Never any fluoride, and no harsh abrasives.

We used the magical remineralizing power of 5% nano-hydroxyapatite to protect your teeth long-term. It's the safest alternative to fluoride!

Unlike messy tube toothpaste, NOBS are easy to store and use anywhere.

Thanks to our unique blend of natural ingredients, NOBS will make your breath as fresh as you look. Instead of gross sweeteners that cover up a natural slightly bitter aftertaste, our organic mint will leave you so kissable. Trust us, your date will thank you.

Cleans Effectively Without Damaging Enamel

With an enviable RDA of 21.38, NOBS Toothpaste Tablets are intentionally designed to help you gently buff out surface stains and break up plaque biofilm without causing damage to your enamel. Thanks, baking soda!

Flex on TSA

NOBS toothpaste tablets don’t apply to the 3.4oz limit. Fly with confidence that you won’t be condemned to a dirty mouth while you travel.

No Mess

Never worry about your toothpaste tube exploding over your other toiletries. NOBS toothpaste tablets come in an air-tight glass jar, free of plastic and without the mess. Unscrew, chew, and renew your mouth.

No Plastic

We want you to disrupt your brushing routine, not your endocrine system. Unlike other brands, our product is free of all plastics and BPAs.

Perfect Size

NOBS toothpaste tablets are individual and perfectly dosed. No more squeezing, no more tube sliding against the edge of your sink and definitely no wasted toothpaste.

Safe for Children

Protecting little ones is our top priority. NOBS provides the safest oral care for pregnant women and their families. Just monitor and ensure that your child can chew and swallow safely before introducing them to NOBS.


This product is not suitable for pets. Humans only, please!

While xylitol is great for supporting the human oral microbiome, it can be toxic to pets. Please keep NOBS away from your furry friends, and contact your veterinarian immediately if consumed by your pet.

Fluoride Free Toothpaste Tablets

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