Present in all lipids, glycerin may come from animal or plant origin, and it can also be synthesized in a laboratory.
By creating a film at the surface of the skin, glycerin helps keep the skin hydrated and aids in the formation of the skin’s natural hydrolipidic film. Scientific research suggests the presence of glycerin in the intracellular (between the cells) layers of the skin would help skin lipids perform their function better1. The majority of dermatological skincare products contain a certain amount of glycerin. American Journal of Contact Dermatitis, Sept 2000, pages 165–169.