Titanium Dioxide (Ci77891)
Titanium Dioxide (CI 77891) is an inorganic oxide used in cosmetics primarily as a UV filter and colorant/opacifier. It provides broad-spectrum UV protection, performing best in the UVB and UVA II range (290–350 nm) and less effectively in the UVA I range (350–400 nm). It works mainly through absorption of UV radiation rather than reflection, contrary to the traditional "physical sunscreen" characterization. Regular (non-nano) particle sizes leave a notable white cast and can be difficult to spread on skin.
Titanium Dioxide offers broad-spectrum UV protection (UVB and UVA II) and is highly photostable, meaning it does not degrade significantly upon sun exposure. It has a favorable safety profile in its regular particle size — it is non-irritating and is not associated with estrogenic or other systemic health concerns linked to some chemical filters. It also functions as an opacifier and colorant in cosmetic formulations.
Nano-sized Titanium Dioxide particles, used to reduce white cast and improve spreadability, raise ongoing safety concerns regarding potential skin penetration, protein complex formation, and free radical generation, though studies as of 2009–2011 had not demonstrated significant percutaneous penetration in sunscreen formulations. Regular (non-nano) Titanium Dioxide is considered to have a good safety profile. Cosmetic restrictions apply (IV 143, VI 27, VI 27a for nano form).
