Xanthan gum is a polysaccharide, a type of carbohydrate that consists of several sugar molecules linked together. It is produced by fermentation of simple sugars. The fermentation process uses the bacterium Xanthomonas campestris, which is where this ingredient's name is derived.
Xanthan gum in skin care is used as a thickener, texture enhancer and to stabilize emulsions, which is a general term for mixtures of disparate substances such as oil and water. Because of this ability, it is also included as an additive in many foods, especially in sauces and salad dressings. https://www.paulaschoice.com/ingredient-dictionary/ingredient-xanthan-gum.html?q=Xanthan%20Gum&fdid=ingredients