Titanium Dioxide

Titanium dioxide is an inert mineral pigment/UV filter typically used at a few percent up to ~25% in sunscreens and is considered non-sensitizing and non-irritating in standard patch testing, including for sensitive skin. In real-world use, irritation is uncommon and usually relates to formulation factors (vehicle, rubbing, or inhalation risk with loose powders) rather than the ingredient itself. Given compromised-skin populations, I rate it as exceptionally gentle rather than perfectly inert. Safety Notes: In commercial skincare, titanium dioxide is seen at very low levels (~0.05–1%) as an opacifier/whitener in lotions, cleansers, and moisturizers (including rinse-off), where it’s not intended to provide UV protection. At the high end, consumer mineral sunscreens and tinted SPF products commonly use ~5–20% titanium dioxide, with some high-coverage stick/cream and high-SPF mineral formulations reaching about 25% to achieve SPF/UVA performance and opacity; these are leave-on products. Regulatory frameworks generally do not set a uniform max % across all markets, but TiO2 is widely permitted in cosmetics/sunscreens with usage constrained in practice by aesthetics, dispersion, and photostability/coverage requirements.