Glycerin is a natural compound (glycerol) used as an emollient and humectant. Emollients are substances that moisturize and soften the skin and decrease itching.  Humectants are also moisturizing agents that pull water into your outer layer of skin (stratum corneum) from either deeper layers of skin or from the air. According to a 2008 (*4) study glycerin can hydrate the outer layers of the skin, improve skin barrier function and skin mechanical properties, provides protection against skin irritants and accelerates wound-healing processes. Further according to a 2016 study (*5), glycerin is “the most effective humectant” in comparison with numerous others including alpha hydroxyl acids, and hyaluronic acid.