Pyrrolidone carboxylic acid (PCA) is a naturally occurring component of human skin and a plays an important role in maintaining the skin’s moisture level. It attracts moisture from the air and helps contributed a smooth feeling to hair and skin.

It can also be derived from plant, fruits, grasses and vegetables so when added to skin care products, it is not irritating even at fairly high concentrations. It is stable in sunlight and is rapidly biodegradable.