Sodium lauryl sulfate shows up frequently in toothpaste, as well shampoos, bubble bath, engine degreasers, floor wax and as a lure and poison to kill fruit flies. With such a varied pedigree, it’s easy to understand why people would question the safety of smearing it across their teeth.
First, what is sodium lauryl sulfate? Principle among its properties in industrial use, it is a surfactant. That is, it lowers the surface tension between liquids or between a liquid and a solid, much the way soap does. The technical term for sodium lauryl sulfate’s job in your toothpaste is “foaming agent.” It’s popular in industrial and commercial uses because it can be derived very cheaply from palm and coconut oil.
What it does not do, according to the American Cancer Society and the International Agency for Research on Cancer (among others), is cause cancer. In spite of an email campaign about a decade old now, no actual studies have shown sodium lauryl sulfate to be carcinogenic. It is an irritant, but you’d need to swallow 16 pounds before it could seriously threaten your health.
All that said, sodium lauryl sulfate is one of the reasons you shouldn’t swallow your toothpaste. Like soap, if it gets into your digestive tract it can cause mild diarrhea. You should also avoid getting it in your eyes, just as you would shampoo. It may prolong canker sores, but does not appear to cause them.
Picking the right toothpaste is an important matter in keeping your teeth healthy. If you’re not sure which toothpaste is right for you family, consult your childrens dentist for recommendations. There are a number of toothpastes available that are free of sodium lauryl sulfate, as well as many organic options. A trained professional can guide you to the best options and help you avoid fads and fear-mongering.