Sodium PCA, or Pyrrolidone Carboxylic Acid, is a sodium salt found naturally in the skin. It acts primarily as a humectant moisturiser, drawing and retaining moisture from the air. As a key component of the skin’s natural moisturizing factor (NMF), it mimics this vital role when applied topically. Humectants like Sodium PCA help maintain skin hydration by attracting and retaining moisture, keeping the skin’s surface supple and intact when combined with natural skin lipids.