What it is
PCA is a cyclized derivative of glutamic acid and is one of the components of the skin's natural moisturizing factor (NMF), the mixture of hygroscopic substances that helps the outer skin layer hold water. As a humectant it attracts and binds moisture, supporting a hydrated, conditioned surface. In cosmetics the free acid and its salts, such as sodium PCA, are common; the acid form can also help adjust formula pH.
Safety & warnings
PCA is a skin-identical humectant and is generally well tolerated. It is not a recognized fragrance allergen and is not considered comedogenic. As with any acid-form ingredient, it is buffered to skin-appropriate pH in finished products.
Origin & sourcing
Found naturally in human skin as part of the natural moisturizing factor; the cosmetic ingredient is produced synthetically, typically from glutamic acid.
Questions everyone asks
Is PCA naturally found in skin?
Yes. PCA is one of the components of the skin's natural moisturizing factor, the blend of substances that helps the outer skin hold onto water.
How is PCA different from sodium PCA?
Sodium PCA is the sodium salt of PCA. Both act as humectants; the salt form is very water-soluble and pH-neutral, while the free acid can also influence formula acidity.