#1 – Sodium Lauryl Sulfate (SLS)
SLS is a foaming agent that is also used in car washes. It’s known to dry out mucous membranes and cause irritation as well as it has been shown to increase the risk of developing cold and canker sores in people who are predisposed to recurrent aphthous ulcers, according to studies.
In some cases, SLS can lead to a peeling-off of the gums. Although some individuals are allergic to Sodium Lauryl Sulfate, it’s generally toxic to human cells and should better be avoided.