Titanium Dioxide (4.8%)
Titanium Dioxide is an inorganic (physical) sunscreen agent conforming to the formula CAS #13463-67-7. It functions as a UV absorber, UV filter, cosmetic colorant, and opacifying agent. Despite being traditionally classified as a "physical" sunscreen that reflects UV light, a 2016 study indicates it works primarily through absorption in the UV spectrum. It is used at 4.8% in this formulation.
Titanium Dioxide provides broad-spectrum UV protection, with particularly strong coverage in the UVB and UVA II range (290–350 nm) and is highly photostable. It has a good safety profile, being non-irritating and largely free from health concerns such as estrogenic effects associated with some chemical filters. Regular (non-nano) particle sizes remain on the skin surface, further supporting its safety.
Nano-sized Titanium Dioxide particles raise concerns about potential skin penetration, possible protein complex formation, and free radical promotion, though studies to date have not demonstrated significant percutaneous penetration. Regular (non-nano) Titanium Dioxide is cosmetically inelegant — it is difficult to spread and leaves a noticeable white cast on the skin. Subject to cosmetic restrictions (IV 143, VI 27, VI 27a for nano form).
