An alcohol rub, also known as a han sanitizer or healthcare personnel hand wash is used as a supplement or alternative to hand washing with soap and water. The active ingredient in alcohol rubs may be isopropanol, ethanol, or (in Europe) n-propanol. A variety of preparations are available, including gels, foam and liquid solutions. Hand sanitizers containing alcohol are more effective at killing germs than soaps and do not dry out hands as much as soaps. Inactive ingredients in alcohol rubs typically include a thickening agent such as Carbomer (a trade name for polyacrylic acid), and humectants such as glycerin and propylene glycol.