The FDA has not updated its general guidance on safety assessments since 2007. Within that time, there has been a significant increase in research on the confluence of toxicology, nanotechnology and human health. The EU updates its guidance regularly with new science available to offer proper safety assessments, with its most recent update published in 2021.

On absorption of UV light, photo-generated titanium dioxide particles create singlet oxygen, superoxide anions (O2-) and hydroxyl radicals (OH-) that are potent free radicals (1,2). Irradiated particles of titanium dioxide can induce oxidative damage to DNA (2) which can lead to the development of mutant cells and skin cancers (3,4,5,6) and lipid peroxidation of essential functions on the cell membrane (7).