Cosmetic grade medium molecular weight hyaluronic acid generally refers to sodium hyaluronate with a molecular weight in the range of approximately 800–1200 kDa. It combines good film-forming properties with moderate permeability. It forms a moisturizing barrier on the skin surface, reducing moisture evaporation while providing continuous hydration to the stratum corneum. Compared to high molecular weight hyaluronic acid, it is lighter and non-sticky; compared to low molecular weight hyaluronic acid, it has longer-lasting moisturizing power. Therefore, it is widely used in lotions, serums, creams, and masks to enhance the skin's immediate hydration and softness.