Can Toothpaste Cause Canker Sores? A Dentist Explains

Yes, toothpaste can potentially cause canker sores in some individuals. Certain ingredients in toothpaste, such as sodium lauryl sulfate (SLS), can contribute to the development of canker sores.

SLS is a surfactant commonly found in toothpaste that can irritate the delicate tissues inside our mouths, leading to the formation of canker sores. Additionally, abrasive substances in toothpaste can also contribute to tissue irritation and ulcer formation, further exacerbating the risk of developing canker sores.

If you experience recurrent canker sores and suspect your toothpaste may be the cause, consider switching ton SLS free toothpaste to see if it helps alleviate the issue.

In this article, I'll explain everything you need to know about canker sores and whether or not your toothpaste might be causing them.

First, what are canker sores?

A kid having canker sores

Often referred to as aphthous ulcers, canker sores are painful lesions that only develop on the soft tissues inside of your mouth. They occur most frequently on the:

  • gums

  • tongue

  • cheeks

  • or throat.

Typically, canker sores are rounded, white sores raised above the soft tissue. They can vary in size and may cause discomfort or pain, particularly when eating, drinking, or speaking.

While the exact cause of canker sores is not fully understood, research suggests that braces and sharp teeth along with potential irritants like sodium lauryl sulfate contribute to their development.

Canker sores are not contagious but can recur intermittently in some individuals.

Signs of a Canker Sore

Signs of Canker Sore

Not to be confused with cold sores, research suggests signs of a canker sore include:

  1. Pain or discomfort: Canker sores often cause pain or a burning sensation, especially when eating, drinking, or speaking.

  2. Lesions: Canker sores begin appearing as a raised, rounded white sore on the soft tissues in your mouth. They may vary in size, from small pinpoint lesions to larger sores.

  3. Redness and inflammation: The area surrounding the canker sore may be red and inflamed.

  4. Difficulty eating or drinking: Due to the pain or discomfort, individuals with canker sores may experience difficulty chewing or swallowing.

  5. Tingling or burning sensation: Some people may notice a tingling or burning sensation in the area before the sore develops.

Further, canker sores can recur periodically in the same location or in different areas of the mouth.

Can certain toothpaste cause canker sores?

Yes, certain toothpaste ingredients, such as sodium lauryl sulfate (SLS), have been associated with an increased risk of developing canker sores for some poeple.

SLS is a foaming agent found in many toothpaste formulations, and its abrasive properties can potentially irritate the delicate tissues inside the mouth. This can  lead to discomfort and the formation of canker sores. Additionally, other ingredients like artificial flavors, preservatives, or dyes may also trigger allergic reactions or irritation in some people, contributing to the development of canker sores.

If you experience recurrent canker sores, switching to a toothpaste without SLS - this may help alleviate your discomfort or symptoms and reduce the likelihood of future outbreaks.

What's the ingredient in toothpaste that causes canker sores?

Sodium lauryl sulfate is the ingredient in toothpaste that is most commonly associated with canker sores. SLS is a surfactant often used in toothpaste for its foaming properties which allows you to more easily distribute the toothpaste throughout your mouth while brushing.

Some studies and anecdotal evidence suggest that SLS can irritate the delicate tissues inside your mouth, potentially leading to the formation of canker sores. If you're prone to getting canker sores and suspect your toothpaste might be a contributing factor, consider switching to a no SLS toothpaste.

Causes of Mouth Sores from Toothpaste

a man brushing his teeth

Mouth sores from toothpaste can arise due to various factors and ingredients to avoid in toothpaste.

Sodium Lauryl Sulfate (SLS), a common foaming agent found in many toothpaste formulations, is known to cause irritation and trigger mouth sores in susceptible individuals. This compound can strip away the natural protective layer of saliva on the gums, resulting in dryness and irritation.

As a result, SLS is one of the most commonly avoided ingredients in toothpaste.

Additionally, some people may experience allergic reactions to certain ingredients in toothpaste, such as flavorings or preservatives, leading to the development of mouth sores, swelling, or redness in the oral cavity.

Let's walk through some of the key causes of most canker sores from toothpaste.

Sodium Lauryl Sulfate

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. However, while SLS can be beneficial, it can have some bad side effects in toothpaste.

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.

Abrasive Ingredients

Abrasive ingredients present in toothpaste, like charcoal, can exacerbate oral tissue irritation and potentially contribute to the formation of mouth sores and cause recurrent canker sores. These abrasives, while effective at removing surface stains and plaque, can be harsh on the delicate tissues of the mouth when used excessively or aggressively.

How to Heal Canker Sores

To heal frequent canker sores, there are several strategies you can employ. First, practicing good oral hygiene by gently brushing your teeth with a soft-bristled toothbrush and using mild, SLS free toothpastes can help prevent further irritation. Additionally, rinsing your mouth with salt water or an over-the-counter mouthwash specifically formulated for oral ulcer relief can help soothe the affected area and promote healing.

Over-the-counter topical treatments, such as gels or patches containing ingredients like benzocaine or hydrocortisone, can provide temporary pain relief and accelerate the healing process. Avoiding acidic or spicy foods and beverages that may exacerbate discomfort can also aid in healing.

In some cases, over-the-counter nonsteroidal anti inflammatory drugs (NSAIDS) can help manage pain associated with canker sores. If the sores persist or worsen despite these measures, we recommend that you consult a dentist or healthcare professional for further evaluation and treatment.

The Best Toothpaste for Canker Sores

For those of us who frequently suffer from canker sores, finding the right oral care products can be the key to managing discomfort and promoting healing.

NOBS Toothpaste Tablets are the standout canker sore toothpaste choice for those prone to these painful ulcers. One of the key reasons is that they're an SLS-free toothpaste, meaning they're not formulated with any sodium lauryl sulfate.

Sodium lauryl sulfate is a common ingredient in many toothpastes that has been linked to the exacerbation of canker sores and mouth ulcers. By eliminating SLS and harsh abrasives from their formula, canker sore toothpastes like NOBS Toothpaste Tablets offer a gentler cleaning experience, reducing the potential irritation that can trigger or worsen canker sores.

NOBS Toothpaste Tablets have a simple, clean ingredient list, featuring only 13 ingredients. This minimalist approach minimizes your risk of allergic reactions which can be a concern with other toothpastes.

Additionally, NOBS stands out as the best choice for canker sore sufferers as it doesn't contain fluoride, or other ingredients known to cause mouth irritation. It includes nano-hydroxyapatite (nHA) to remineralize teeth, ensuring comprehensive dental care without compromising effectiveness.

Summary: Canker Sores from Toothpaste

Canker sores from toothpaste may arise due to irritation or allergic reactions to specific ingredients, such as sodium lauryl sulfate (SLS) or other abrasive substances commonly found in toothpaste formulations. SLS, in particular, is known to disrupt the protective layer of saliva in the mouth, leading to dryness and irritation of the oral tissues. Additionally, some individuals may be hypersensitive to certain additives or flavorings in toothpaste, resulting in inflammatory reactions that manifest as canker sores.

For these reasons, SLS free toothpaste is becoming increasingly popular.

Frequently Asked Questions

Why does my toothpaste give me canker sores?

Your toothpaste may be causing canker sores due to sodium lauryl sulfate (SLS), an ingredient found in many toothpaste formulations. SLS can disrupt the protective layer of saliva in the mouth, leading to dryness and irritation of the oral tissues, which may trigger the development of canker sores in susceptible individuals. Additionally, abrasive substances in toothpaste, such as certain types of silica, may contribute to tissue irritation and ulcer formation. If you're experiencing recurrent canker sores from your toothpaste, consider switching to SLS free toothpaste.

What toothpaste is best for canker sores?

SLS free toothpastes with hydroxyapatite are the best for canker sores. These toothpastes are formulated with sodium lauryl sulfate (SLS), an ingredient in many toothpastes that is known to cause mouth irritation, ulcers, and dryness.

Can fluoride toothpaste cause sore mouth?

Yes, fluoride toothpaste can cause cancer sores if it contains sodium lauryl sulfate (SLS), an ingredient found in many toothpaste formulations. SLS can disrupt the protective layer of saliva in the mouth, leading to dryness and irritation of the oral tissues, which may trigger the development of canker sores in susceptible individuals. Additionally, abrasive substances in toothpaste, such as certain types of silica, may contribute to tissue irritation and ulcer formation. If you're experiencing recurrent canker sores from your toothpaste, consider switching to SLS free toothpaste.

What toothpaste does not cause mouth ulcers?

SLS free toothpastes typically do not cause canker sores. These toothpastes are formulated with sodium lauryl sulfate (SLS), an ingredient in many toothpastes that is known to cause mouth irritation, ulcers, and dryness.

Is my toothpaste causing mouth sores?

Yes, your toothpaste may be causing mouth sores if it contains sodium lauryl sulfate (SLS), an ingredient found in many toothpaste formulations. SLS can disrupt the protective layer of saliva in the mouth, leading to dryness and irritation of the oral tissues, which may trigger the development of canker sores in susceptible individuals. Additionally, abrasive substances in toothpaste, such as certain types of silica, may contribute to tissue irritation and ulcer formation. If you're experiencing recurrent canker sores from your toothpaste, consider switching to SLS free toothpaste.


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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