Titanium dioxide can be both safe and unsafe, depending on its use. When inhaled, titanium dioxide is considered possibly carcinogenic to humans. This means that in products that contain powdered titanium dioxide like loose powders, pressed powders, eyeshadows, and blushes in which the makeup is in powder form, titanium dioxide can be inhaled. Titanium dioxide is also an occupational chemical of concern, as workers might inhale titanium dioxide when manufacturing products.

Lyophilized vitamins@P25TiO₂NPs were obtained through the described methods with excellent reproducibility and yield: over 99% of initial P25TiO₂NPs were functionalized.

The risks associated with titanium dioxide exposure depend on a variety of factors, including the form of the mineral, the route of exposure (such as being inhaled or consumed), and the duration and intensity of exposure.

Even though it is one of the most-produced chemicals, the real and potential benefits of titanium dioxide are not without controversies. Dust inhalation may cause breathing problems. Titanium dioxide has been classified by the International Agency for Research on Cancer as an Group 2B carcinogen, a “possible carcinogen to humans,” based on studies of rats that inhaled the substance.

Lithopone, a white pigment composed of a mixture of barium sulfate and zinc sulfide, is commonly used in the leather industry as a coloring agent. Leather suppliers around the world rely on lithopone to achieve the desired color and finish on their products.

Product Name: Lithopone

For a review published in 2023 in the journal Environmental Pollution, researchers examined E171 as a possible factor promoting obesity-related metabolic disorders. Because gut microbiota play an important role in immune function maintenance and development, and because titanium dioxide as a food additive has been shown to alter gut microbiota, researchers wanted to review “the dysregulations along the gut microbiota-immune system axis after oral TiO2 exposure compared to those reported in obese or diabetic patients, and to highlight potential mechanisms by which foodborne TiO2 nanoparticles may increase the susceptibility to develop obesity-related metabolic disorders.” The study authors discovered recurrent changes in the gut microbiota composition when exposed to titanium dioxide nanoparticles, with an imbalance of intestinal symbiotic microbiota. These changes and imbalances were also reported and played a role in the development of obesity, the authors wrote. This highlights “foodborne TiO2 nanoparticles as an endocrine disruptor-like chemical promoting obesity-related disorders,” the authors concluded.

Some food products will include titanium dioxide on their nutrition label. But again, it can be hard to tell for those who don't list the ingredient.