Sodium Lauryl Sulfate, or SLS, is found in virtually every major brand of toothpaste. It is an effective and inexpensive detergent. Unfortunately, it has also been linked (in 3 of 4 independent clinical trials) to a significant increase in number of canker sores when compared to brushing with SLS-free toothpaste. (Note: The only other common toothpaste ingredient found to indicate a slightly elevated canker sore risk is Cocoamidopropyl Betaine or CAPB. Verve toothpaste is also CAPB-free).

There have been four clinical trials that have looked at the relationship between canker sores and brushing with toothpaste containing Sodium Lauryl Sulfate ("SLS toothpaste"), versus using a toothpaste without Sodium Lauryl Sulfate ("SLS-free toothpaste"). In the briefest terms, the results of these trials, with regard to canker sore occurrences are:

Trial 1) SLS toothpaste is bad. (preliminary study)

Trial 2) SLS toothpaste is bad and toothpaste containing CAPB is a little bit bad. (larger followup study)

Trial 3) SLS toothpaste is bad. (new study)

Trial 4) Inconclusive: while the study subjects faired better, on average, during SLS-free toothpaste periods than during the SLS-containing toothpaste periods, the effect was not as pronounced as in the other trials, and the statistical analysis of the results could not decisively rule out the possibility of a "chance" correlation. In the analysis of number of canker sores, the probability of a chance correlation was 6.6% (and therefore the probability of a real correlation was 93.4%). By convention, the probability of a chance correlation must be at or below 5% for the result to be considered statistically significant.

For references and a more detailed look at the research results, click here.
For articles on CANKER SORE PREVENTION, click here.
For articles on CANKER SORE TREATMENT, click here.
For articles on CANKER SORE CAUSES, click here.
For articles on CANKER SORES and SLS Free Toothpaste, click here.
To visit our SLS-Free toothpaste home page, click here.