Calcium carbonate is an inorganic mineral (CaCO₃) used extensively as a bulking agent, opacifier, absorbent, and abrasive in personal-care systems. In skincare, it contributes elegant payoff and slip in pressed/loose powders and sticks, provides visual opacity to blur imperfections, and improves pick-up/pressability in anhydrous formats. Its high oil-absorption capacity enables sebum-mattifying benefits for combination and oily skin, while its particulate nature can deliver very mild, non-scratching polishing in cleansers and masks when appropriate particle‐size distributions are chosen. Calcium carbonate is chemically stable in neutral/alkaline media but will react with acidic phases; this informs pH-aware formulation design and explains why it excels in neutral masks, body powders, deodorant sticks, foundations, and SPF-adjacent (non-filter) opacifying roles.

In hair care and scalp-care, calcium carbonate’s absorbency supports oil-control formats such as dry shampoos and scalp mattifiers, improving freshness and volume without tack. As a rheological/texture aid, it enhances compressibility in powder shampoos and improves payoff in sticks/balms. The mineral is non-volatile and non-sensitizing in typical topical use, and it is broadly permitted in cosmetics worldwide; in the U.S. it is additionally listed as a color additive (exempt from certification) for cosmetics (not for the eye area), which formulators sometimes leverage for tone and opacity control in complexion products.