Glycerin, also called glycerol or glycerine, is a humectant present in all natural lipids (fats), whether animal or vegetable. It can be extracted from natural substances by hydrolysis of fats and by fermentation of sugars; it can also be synthetically produced, which is usually the case with modern skin care products, as it results in highly purified glycerin.
Glycerin is a skin replenishing and skin regenerating ingredient, meaning it is a substance found naturally in the skin that helps establish normal balance and hydration. It is one of the many substances in the skin that help maintain a healthy look and feel, defend against dryness and work to maintain the skin's moisture level. Essentially, glycerin is a master of hydration and works best when combined with other replenishing and emollient ingredients.