Calcium Carbonate

Calcium carbonate is primarily a mineral abrasive/bulking agent used in products like toothpastes, powders, and some cleansers; it is generally non-sensitizing but can be physically irritating when particles are coarse or used with friction on compromised skin. Clinically, irritation is typically mechanical (dryness, micro-abrasion, stinging on eczematous or barrier-impaired areas) rather than allergic, so while many tolerate it well, reactive or broken skin can flare—warranting a mild score for safety. Safety Notes: In commercial skincare, calcium carbonate appears at very low levels (~0.1–1%) mainly as an opacifier/whitener, rheology modifier, or mild buffering/absorbent in creams and cleansers. The highest consumer-available levels are found in rinse-off dentifrices (toothpastes) and some exfoliating/cleansing powders where it functions as the primary abrasive/filler, commonly ~20–50% and observed up to ~60% in high-abrasive whitening formulations. It is uncommon in leave-on facial products above a few percent due to sensory/whitening and particulate residue, so the upper end of the range is largely driven by rinse-off oral care and wash-off exfoliant formats.