I was bad enough at high school chemistry that my resourceful teacher asked me to step away from the Bunsen burner (thereby, he believed, lowering the risk of a classroom explosion) and instead write profiles of famous chemists. But I was allowed to conduct experiments involving pH factor—the measure of the activity of hydrogen ions in a solution, or acidity. Did you know that a hydrangea produces pink flowers when the soil has a pH of 6.8 or higher (more alkaline) and blue flowers when the soil has a pH of 6 or below (more acidic)? Is that interesting, or what? Sorry…you asked about skincare products. Cleansers and toners are alkaline—hand soap typically has a pH of around 9 or 10, for example—because alkaline molecules bind to dirt and accumulated oils you want to wash off. For your face, you want a product that's alkaline enough to get your skin clean but not so alkaline that it will strip it of the oils it needs. It's unlikely that a cleanser or toner on the market today would have a pH that was not balanced (too high), because if it did it would be so drying that no one would want to use it, says Amy Wechsler, MD, a dermatologist and psychiatrist in private practice in New York City.

Bottom Line: A claim that a product is pH balanced is more marketing tool than useful information.