These are in a lot of things. I've only been able to find out that they can be either vegetable or animal derived, but I don't know how they are derived from animals. I'm a vegetarian, not a vegan, so if it's just from milk or something like that, then it's cool. However, if it's actually animal parts, I'd like to know. Does anyone have any information on this? Also, glycerin.
Many are veg. I think it's cheaper to get it from veg oils. However, it all depends on the product. What you can do is email the company and they will tell you. If it came from animal sources, it's likely that it wouldn't be milk, but the rendered fat.