Citric acid is an organic alpha hydroxy acid used in many skin-care products and food products. It’s a natural preservative found in a variety of fruits and vegetables (mostly lemons, limes and oranges) that also acts as a pH-balancing agent in creams and gels as well as an exfoliant in chemical peels. Citric acid is also a benign cleaning agent and is used to flavor foods with a “sour” taste.