The idea that glycerin can coat teeth and consequently prevent saliva from touching and remineralizing enamel seems to have originated from one source: Dr. Gerard F Judd Ph.D. In 1997, Dr. Judd self-published a book called ‘Good Teeth Birth To Death’. His book doesn’t seem to provide any references that support his claim about glycerin coating teeth. His statement about glycerin is actually from a letter he wrote to his followers in 2001. In the letter, he says that, “All toothpastes make a barrier of glycerine on the teeth which would require 20 rinses to get it off.”
As a result of this one data point, there are several influencers in the wellness sphere who are against including glycerin in oral health products. Even we here at OraWellness were influenced by this information for some time.
However, after talking with several chemists about this, our confidence in Dr. Judd’s perspective has been shaken. All of the chemists who we’ve asked about the risk of glycerin acting like a ‘car wax’ and inhibiting remineralization have said that it’s not possible for glycerin to coat teeth because glycerin is highly water soluble. In other words, because glycerin is highly water soluble, it does not leave a coating on teeth, and it would be easily washed away by saliva if it were left on teeth.
As a consideration on using an oral health product with glycerin in it, we also think it wise to consider the quantity of glycerin in the product. Many toothpastes have glycerin in rather high amounts in their formulas. If you look at the ingredient list on any product, manufacturers are required to list ingredients from highest amount to lowest amount. So, taking a peek at any toothpaste product ingredient panel should help you determine whether the formula is relying on glycerin to fill the tube (it’s an inexpensive ingredient) or if glycerin is serving some other function and is a less prominent ingredient in the formula.
We hope that this information on glycerin helps provide you with more context in which to make an educated choice.