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Will Special SLS-Free Toothpaste Prevent Canker Sores?

Many readers have found that eliminating toothpaste with SLS (sodium lauryl sulfate) helps them avoid canker sores. What is SLS anyway?

Do you pay attention to the kind of toothpaste you use, beyond the flavor? The American Dental Association (ADA) wants you to use a toothpaste with fluoride to prevent cavities. But many visitors to this website are more interested in what is not in their toothpaste! They tell us that seeking out toothpaste that does not contain the foaming agent SLS, also known as sodium lauryl sulfate, helps them avoid canker sores.

Taking Care of Recurrent Canker Sores:

Q. My father and I have both suffered with canker sores all our lives. I’ve heard of eating kiwi fruit to speed healing, and in a recent column you wrote about sauerkraut.

A few years ago, a dental hygienist told me that canker sores are caused by sensitivity to sodium lauryl sulfate, a foaming agent present in many but not all toothpastes. Since I changed toothpastes, I have dramatically fewer canker sores. Even when I bite the inside of my mouth, the sore spot clears within a day instead of the two weeks it used to take. SLS-free toothpaste has made my life more pleasant.

A. You are not the only reader who has told us that avoiding sodium lauryl sulfate (SLS) reduces the likelihood of canker sores. There is surprisingly little research addressing this topic, given that so many products contain this foaming agent.

One systematic reviewof the medical literature published in the Journal of Oral Pathology & Medicine (May 2019)  concluded that use of SLS-free toothpastes helped control aphthous ulcers (canker sores).

SLS-Free Toothpaste Makes Mouth More Comfortable:

Sodium lauryl sulfate plays a key role in personal care products. It foams. Chemists call SLS a surfactant. That means it reduces the surface tension of liquids.

Surfactants are in your dish detergent because such chemicals make it easier to dissolve oil and grease. These “surface active agents” are also good at creating foam. That’s why you will find SLS in shampoos, conditioners, liquid soap, bubble bath, hand sanitizers, shower gels, mouthwash and toothpaste.

People like foam. It reassures them that something is happening, whether it’s in the kitchen sink or in the shower. But a lot of readers tell us that SLS in toothpaste contributes to canker sores. Here is the most recent story from a reader who wanted foam but did not want recurrent canker sores:

Toothpaste without SLS:

“When I was a kid, I used to get horrible canker sores. My mother treated them with silver nitrate, which hurt like heck.

“After my braces came off, I took better care of my teeth and brushed more frequently. I didn’t have as many canker sores and thought it was because of the brushing.

“When I hit menopause though, the canker sores were back with a vengeance. Doctors didn’t have any suggestions, but I read in your newspaper column that toothpaste without sodium lauryl sulfate (SLS) might help. I tried it and it did reduce the canker sores, but I never liked the toothpaste I was using. It had no fluoride and it didn’t foam.

“My daughter and I went to Europe a few years ago. We travelled lightly and I figured I would use her toothpaste.

“I got a canker sore right away, but when we were in Paris our hotel was down the street from a pharmacy. There I found a toothpaste with fluoride but no SLS. It worked perfectly to clean my teeth without causing canker sores. When we got home, I checked online and found it. It’s called Elmex Sensitive Toothpaste.”

A. Many readers have reported that toothpaste containing SLS triggers their canker sores. By the way, doctors and dentists refer to frequent canker sores as recurrent aphthous stomatitis or RAS for short. Aphthous ulcers is another term that is used to describe these painful lesions.

A systematic review of the medical literature concludes that people with frequent mouth sores might do better if they avoid sodium lauryl sulfate toothpaste (Journal of Oral Pathology & Medicine, May, 2019):

“In conclusion, the qualitative and quantitative synthesis of the eligible trials for this review showed that use of SLS‐free consistently reduced all four parameters of ulcers measured. The available evidence suggests that patients with RAS may benefit from using SLS‐free dentifrices for their daily oral care.”

Other Readers Report SLS-Free Toothpaste Helps:

Q. I had canker sores for years until I discovered Biotène toothpaste. It is formulated especially for people with dry mouth and does not contain sodium lauryl sulfate.

My gums are healthier, and I’ve had no cavities since it contains fluoride. It is more expensive but it’s worth it not to suffer from canker sores.

A. We have heard from many readers that the foaming agent SLS (sodium lauryl sulfate) can be irritating to their mouths and gums. A toothpaste without SLS, like Biotène, may be a good choice for someone like you.

Looking for Toothpaste That Won’t Aggravate Canker Sores:

Q. I suffered for years with chronic canker sores. I read that SLS (sodium lauryl sulfate) in toothpaste can trigger this painful problem. How do I find toothpaste without SLS?

A. Some readers report that Biotène toothpaste is SLS-free and helps reduce canker sores (known as aphthous ulcers in medical lingo). Certain toothpaste options from Tom’s of Maine, Rembrandt and Sensodyne Pronamel are also devoid of SLS. Read the labels carefully to make sure the one you purchase does not contain sodium lauryl sulfate.

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Judith had this to say:

“It is very true that toothpaste can cause canker sores and in my case fever blisters also. I am now using WELEDA Salt Toothpaste and am free of the canker sores. Tom’s of Maine is also good. No SLS in either of these.”

LGF made this suggestion:

“I am a dental hygienist. For years, I have cautioned patients to be aware of mouth irritations, cracks in the corners of their lips, or sensitive teeth when they changed toothpaste brands. A lot of tartar-control and whitening toothpastes can cause irritations and sensitive teeth. A patient who often has mouth ulcers told me once that they were almost entirely eliminated by rinsing with Listerine everyday. That made a lot of sense to me, and I pass that info along to all my patients with mouth ulcers.”

TC agrees with the Listerine recommendation:

“I get canker sores on my tongue whenever I eat spicy foods (chile, jalapenos), cinnamon candy disks, fresh or canned pineapple or Starburst candy  and when I’m stressed. What works almost immediately is Listerine. I rinse three times a day and before bedtime.

“There is one other mouthwash that helps too. It’s Dr. Tichenor’s Peppermint mouthwash concentrate. Do not use full strength nor swallow. Dilute with 5 parts warm water and use as needed. It is a little pricey but well worth the positive results. By morning, my canker sores are almost gone but I continue rinsing for several days.

“I use this same mouthwash (Dr. Tichenor’s) for sore throat and by morning my throat feels a lot better. These are my personal preferences. If you try them, I hope they give you some well deserved relief.”

Another reader chimed in on toothpaste with SLS:

“I am so grateful that finally after years and years of suffering with canker sores, I found that a simple change to a non SLS toothpaste immediately halted any further sores within 5 days. Sensodyne Pronamel has made a world of difference to me. I have also started taking lysine capsules and using a recommended non alcohol based mouthwash.

“The thing I’m mad at most are the toothpaste companies who put in this ingredient. It is only there to create a foaming action, with no benefits at all. However, it also causes a small percentage of people to suffer with mouth ulcers with no idea as to why they are getting them. If you have constant canker sores, I can highly recommend this simple change of using a non SLS toothpaste.”

Home Remedies for Canker Sores (Aphthous Ulcers):

Not everyone is sensitive to sodium lauryl sulfate. Some people get canker sores for other reasons: biting the cheek, eating pretzels or potato chips and abrading the cheek or for no obvious reason. If SLS is not the culprit, here is a link to some home remedies that might be beneficial:

Helpful Home Remedies for Canker Sores
Finding the right remedy for canker sores may require some trial and error, but there are many that may work.

and then there is Kiwi Fruit:

Can Kiwi Fruit Overcome Horrible Canker Sores?
Many readers report that eating kiwi fruit can help horrible canker sores heal quickly. Perhaps the anti-inflammatory compound actinidin is responsible.

Share your own experience with SLS below in the comment section. And if you have a favorite home remedy for canker sores, please tell us about it. If you found this article helpful, please share it with friends and family by scrolling to the top of the page and clicking on email, Facebook or Twitter. Thank you for supporting our work. And if you would like to eliminate ads from our website, you can support us by going ad-free at this link.

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About the Author
Joe Graedon is a pharmacologist who has dedicated his career to making drug information understandable to consumers. His best-selling book, The People’s Pharmacy, was published in 1976 and led to a syndicated newspaper column, syndicated public radio show and web site. In 2006, Long Island University awarded him an honorary doctorate as “one of the country's leading drug experts for the consumer.”.
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