Humectants retain moisture so that the dentifrice does not dry out. Humectants function by binding and holding the solvent in the dentifrice. Water is the solvent used in most dentifrices. Humectants, such as glycerin and sorbitol, also inhibit bacterial growth and provide flowability to the dentifrice. Humectants and solvent combined represent approximately 75% of a typical dentifrice formulation.