Is SLS in Toothpaste Harmful? What You Need to Know
- SLS (sodium lauryl sulphate) is a foaming agent in most toothpastes , not a cleaning agent
- It is not a carcinogen. The American Cancer Society and NIH both confirm this clearly
- It is a known irritant for some people, linked to mouth ulcers, gum sensitivity, and dry mouth
- A 2019 systematic review found SLS-free toothpaste reduced mouth ulcers by up to 64%
- Most people tolerate SLS without issues. Sensitive individuals are the ones who benefit most from switching
- SLS-free toothpaste and Ayurvedic tooth powder are both effective, gentler alternatives
Turn over any toothpaste tube in your bathroom right now. Scan the ingredients. Somewhere in that list you will almost certainly find it: sodium lauryl sulphate, or SLS.
It has been in toothpaste since the 1930s. Around 90% of mass-market toothpastes still contain it today. Most people have used it every single day without giving it a second thought.
So when people started asking whether SLS is actually harmful, the question seemed almost absurd at first. Something used for nearly 100 years, by billions of people, every day, how could that possibly be a concern?
The honest answer is nuanced. SLS is not dangerous for most people. But for a specific group, it may be quietly responsible for some very real oral health problems. Here is what the research actually says.
What Is SLS and Why Is It in Toothpaste?
Sodium lauryl sulphate (SLS) is a synthetic detergent and surfactant, derived from coconut or palm oil, that produces foam and helps distribute toothpaste evenly across the teeth and gums during brushing. Toothpastes typically contain 0.5% to 2.5% SLS by weight, according to a review published in Myacare Medical Journal.