The production of Chinese anatase titanium dioxide involves a series of complex chemical processes, including hydrolysis and calcination of titanium precursors. These processes result in the formation of nanoscale particles of anatase titanium dioxide, which exhibit enhanced properties such as increased surface area and improved reactivity. The size and morphology of these nanoparticles can be controlled during the synthesis process, allowing for the production of tailored materials with specific properties for different applications.

French researchers studied how and where E171 nanoparticles enter the bloodstream, first studying the route through pigs and then in vitro with human buccal cells, for a 2023 study published in the journal Nanotoxicology. The research showed that the nanoparticles absorbed quickly through the mouth and then into the bloodstream, before damaging DNA and hindering cell regeneration.

Although the evidence for general toxic effects was not conclusive, on the basis of the new data and strengthened methods we could not rule out a concern for genotoxicity and consequently we could not establish a safe level for daily intake of the food additive, commented Matthew Wright, member of the EFSA's Food Additives and Flavourings Panel in a press statement.