Does SLS-Free Toothpaste Help Canker Sores?What Trials Found
Breath & MouthArticleMany toothpastes contain sodium lauryl sulfate (SLS), a foaming detergent. For people with repeat canker sores, switching to an SLS-free paste is a popular tip. In an early Norwegian study, ulcers dropped from 14 to 5 over three months after switching. A larger Korean trial found SLS-free paste didn't cut the number of ulcers but made them heal faster and hurt less. A review of four trials leaned in favor. Here's what to know.
Repeat canker sores, the small, painful ulcers inside the mouth, are common. One easy change often suggested is a toothpaste without sodium lauryl sulfate (SLS), a foaming detergent used in many brands.1 Here’s what the trials show.
The early study
In Oslo, 10 people with frequent canker sores used a toothpaste with SLS for 3 months, then one without SLS for 3 months.1
- Ulcers fell from about 14 to about 5 over the three months.1
It was very small, and the order of toothpastes wasn’t randomized.
The larger trial
A double-blind trial in Seoul gave 90 people an SLS-free and an SLS-containing paste, 8 weeks each, in random order.2
| Outcome | SLS-free compared with SLS paste |
|---|---|
| Number of ulcers | No difference2 |
| Number of episodes | No difference2 |
| How long ulcers lasted | Shorter2 |
| Pain | Lower2 |
Putting the trials together
A 2019 review of 4 crossover trials with 124 people found SLS-free toothpaste reduced the number of ulcers, how long they lasted, how often they came and how much they hurt.3 The authors said people with repeat canker sores may benefit, but better trials are needed.3
What this means for you
- Check your tube for “sodium lauryl sulfate.”
- Try an SLS-free paste for at least 8 weeks, the length of each phase in the Seoul trial.2
- Keep a simple log of how many sores you get and how long they last.
- Look for other triggers too; see why do I keep getting canker sores?
Try: “I get canker sores every few weeks. Could my toothpaste be part of it, and is there anything else we should check, like iron or B12?”
Is It My Breath? covers mouth sores that need a look in Chapter 8, “Stones, Throats and Tongues,” in a section called “Patches That Need a Look,” which flags any mouth ulcer lasting more than three weeks. Its Breath Log keeps one line a day, including what you tried, so a toothpaste switch sits beside your notes. See the book.
This article is for general educational purposes only and is not medical advice. It isn't a substitute for diagnosis or treatment from a qualified healthcare professional who knows your health history. See a dentist or doctor for a mouth sore that hasn't healed in about three weeks, sores that are very large or keep coming back often, or sores with fever, weight loss or bowel symptoms. Girl Playbook does not endorse any specific product, test, or provider.
Girl Playbook sells this book. It provides education and worksheets, not individualized medical care.
Sources
The research behind this article, in the order it’s cited. How we source our articles.
- Acta Odontologica Scandinavica (abstract via PubMed), 1994Sodium lauryl sulfate and recurrent aphthous ulcers. A preliminary study (opens in a new tab)abc
- Oral Diseases (abstract via PubMed), 2012Effect of sodium lauryl sulfate on recurrent aphthous stomatitis: a randomized controlled clinical trial (opens in a new tab)abcdef
- Journal of Oral Pathology & Medicine (abstract via PubMed), 2019Effect of sodium lauryl sulfate on recurrent aphthous stomatitis: A systematic review (opens in a new tab)ab
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