Magnesium oxide (MgO) is an inorganic compound that is widely used in cosmetic formulations as a fine, white powder. In creams, powders, or lotions, it serves as a white pigment (CI 77711), which provides the formulation with opacity or visual brightness. In addition, it helps absorb excess sebum, resulting in a matte complexion. At the same time, its buffering effect helps stabilize the product’s pH and contributes to the desired opacity and consistency. Due to its properties, magnesium oxide is a common excipient in decorative cosmetics and sunscreen products.(1)