Another big difference between certain types of natural and regular toothpaste is whether or not they test on animals or use ingredients that are derived from animals. If you're vegetarian or concerned about animal welfare, it may be important to you to find a toothpaste that doesn't contain animal ingredients. One ingredient that can come from either animal- or plant-based sources is glycerin. The majority of glycerin used today is vegetarian, according to the Vegetarian Resource Group.