Dr Peter  Dingle (BEd, BSc, PhD)

Titanium dioxide is typically micronized and coated for use in cosmetics products. The micronizing makes this somewhat heavy-feeling ingredient easier to spread on skin, plus a bit more cosmetically elegant. Micronized titanium dioxide is much more stable and can provide better sun protection than non-micronized titanium dioxide.

However, most dermatologists will warn their patients not to rely on mineral makeup alone in order to be protected by the sun’s rays. This is because there can be quite a bit of variation with mineral foundation – not only with how much we apply but how much titanium dioxide the foundation contains.

A  2023 study published in the journal Environmental Research, scientists examined the effect of titanium dioxide nanoparticles on important gut bacteria in mice. Their results showed “the growth inhibitory effects could be associated with cell membrane damage caused by titanium dioxide nanoparticles to the bacterial strains. Metabolomics analysis showed that TiO2 NPs caused alterations in multiple metabolic pathways of gut bacteria, such as tryptophan and arginine metabolism, which were demonstrated to play crucial roles in regulating gut and host health.” The researchers also found that four different neuroprotective metabolites “were significantly reduced” in urine and in vitro bacteria and vivo urine samples. The researchers concluded: “Increasing evidence implies that the gut microbiome plays a profound role in regulating host metabolism. Our results illustrated that TiO2 NPs hindered the growth of four beneficial gut bacterial strains.”

BaSO4 + 4C=BaS + 4CO

Health effects

Lithopone, an alternative to titanium dioxide