Glycerin is a sugar alcohol: a hybrid of sugar and alcohol molecules used as a low calorie substitute for sugar. There are three types of glycerin, animal glycerin made from animal fats like tallow, vegetable glycerin made from vegetable fats such as soybean, coconut or palm oils, and synthetic glycerin made from petroleum. Usually the product is glycerine and the ingredient is glycol: for example glycerin syrup is made mostly of glycol. Vegetable Glycerins are made by heating triglyceride-rich fats under pressure or together with a strong alkali, such as lye. In addition to being a food additive, glycerins are also commonly used in pharmaceutical drugs and cosmetics.
Can cause digestive issues and discomfort such as bloating, gas, diarrhea, and stomach pain as well as headaches.
Sugar Alcohols: Good or Bad?https://www.healthline.com/nutrition/sugar-alcohols-good-or-bad
What Is Vegetable Glycerin? Uses, Benefits and Side Effectshttps://www.healthline.com/nutrition/vegetable-glycerin#uses