Pullulan is a naturally occurring substance derived from the fungus Aureobasidium pullulans. It is commonly used for breath freshening strips. In cosmetics, pullulan gives an instant tightening effect by creating a film that stays on the surface of the skin. This effect is purely cosmetic and washes away after use.
Int J Toxicol. 2012 Sep-Oct;31(5 Suppl):245S-60S. doi: 10.1177/1091581812461381. Review.