Titanium dioxide (TiO2) is renowned for its brightness, high refractive index, and stability. It comes in two primary crystalline forms rutile and anatase. Rutile is predominantly used in the production of tires due to its superior characteristics, including high UV resistance, durability, and excellent pigmentary properties. These features make TiO2 an ideal choice for enhancing the performance and longevity of tire products.

A legal additive in the United States, titanium dioxide is used in everything from food to consumer goods and the U.S. Food and Drug Administration says regulated use of the product as a color additive in food is safe within certain restrictions.

Furthermore, this packaging has been shown to have both antibacterial and photocatalytic activity, the latter of which reduces ultraviolet (UV) exposure (5Trusted Source, 6).

Prof Matthew Wright, both a member of the FAF Panel and chair of EFSA’s working group on E 171, said: “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.”

The basic scenario of resistive switching in TiO₂ (Jameson et al., 2007) assumes the formation and electromigration of oxygen vacancies between the electrodes (Baiatu et al., 1990), so that the distribution of concomitant n-type conductivity (Janotti et al., 2010) across the volume can eventually be controlled by an external electric bias, as schematically shown in Figure 1B. Direct observations with transmission electron microscopy (TEM) revealed more complex electroforming processes in TiO₂ thin films. In one of the studies, a continuous Pt filament between the electrodes was observed in a planar Pt/TiO₂/Pt memristor (Jang et al., 2016). As illustrated in Figure 1C, the corresponding switching mechanism was suggested as the formation of a conductive nanofilament with a high concentration of ionized oxygen vacancies and correspondingly reduced Ti³⁺ ions. These ions induce detachment and migration of Pt atoms from the electrode via strong metal–support interactions (Tauster, 1987). Another TEM investigation of a conductive TiO₂ nanofilament revealed it to be a Magnéli phase Ti_nO_2n−1 (Kwon et al., 2010). Supposedly, its formation results from an increase in the concentrations of oxygen vacancies within a local nanoregion above their thermodynamically stable limit. This scenario is schematically shown in Figure 1D. Other hypothesized point defect mechanisms involve a contribution of cation and anion interstitials, although their behavior has been studied more in tantalum oxide (Wedig et al., 2015; Kumar et al., 2016). The plausible origins and mechanisms of memristive switching have been comprehensively reviewed in topical publications devoted to metal oxide memristors (Yang et al., 2008; Waser et al., 2009; Ielmini, 2016) as well as TiO₂ (Jeong et al., 2011; Szot et al., 2011; Acharyya et al., 2014). The resistive switching mechanisms in memristive materials are regularly revisited and updated in the themed review publications (Sun et al., 2019; Wang et al., 2020).

In short, no, research demonstrates that E171 is safe when consumed in normal situations.

Moreover, how we're exposed to an ingredient matters significantly in terms of our health and potential toxicity.   

Research shows that inhaling titanium dioxide particles in significant quantities over time can cause adverse health outcomes. Unless you work in an industrial setting, inhaling substantial amounts of titanium dioxide is highly unlikely. 

Research supports that applying titanium dioxide to the skin in the form of sunscreens, makeup, and other topical products does not pose a health risk. 

Overwhelmingly, research that's relevant to human exposure shows us that E171 is safe when ingested normally through foods and drugs (1,2).

Again, other research suggests that E171 could cause harm; however, those research processes did not design their studies to model how people are exposed to E171. Research that adds E171 to drinking water, utilizes direct injections, or gives research animals E171 through a feeding apparatus is not replicating typical human exposure, which occurs through food and medicine consumption.

Read more in-depth about the titanium dioxide risk at go.msu.edu/8Dp5. 

Fig. 1. Weight loss (%) of vitaminB2@P25TiO₂NPs.

When used in an ultrafine-grade formulation, titanium dioxide becomes transparent to light, effectively making it an absorber of UV light. And because its particles are so small in this form, titanium dioxide creates a transparent barrier that absorbs UV light.

Numerous studies have linked titanium dioxide to genotoxicity and cytotoxicity. Genotoxicity refers to a chemical’s potential to cause DNA damage, which can, in turn, lead to cancer. Cytotoxicity is a general term that refers to a characteristic of being harmful to cells.  

All in all, Titanium Dioxide is a famous sunscreen agent and for good reason, it gives broad spectrum UV protection (best at UVB and UVA II), it's highly stable, and it has a good safety profile. It's definitely one of the best UV-filter agents we have today, especially in the US where new-generation Tinosorb filters are not (yet) approved. 

This work confirms previous studies that show P-25 and other untreated anatase 377 nanoparticles should not be employed in sunscreens because the toxicity of P25TiO2NPs under UV radiation is significant.

lithopone supplier 30% is a perfect alternative to titanium dioxide in all natural and synthetic pigmented elastomers, as it is non-abrasive and extremely acid resistant. 

There are numerous manufacturers of titanium dioxide; the largest include Delaware-based Chemours (a spin-off of DuPont Chemical), Texas-based Kronos, and China-based Lomon Billions Group, all of which manufacture pigments for use in products like paints, coatings, and plastics. UK-based Venator is a major supplier of titanium dioxide used in food and cosmetics, along with paints, paper, plastic, and more. As a pigment, it is called Pigment White 6 (PW6), titanium white, or CI 77891. As a food additive, it is known as E171.

Freshwater algae show low-to-moderate susceptibility to TiO₂ exposure, with more pronounced toxic effects in the presence of UV irradiation. It has also been shown that nano-sized TiO₂ is significantly more toxic to algae Pseudokirchneriella sub-capitata than submicron-sized TiO₂. Hund-Rinke and Simon  reported that UV irradiated 25 nm TiO₂ NPs are more toxic to green freshwater algae Desmodesmus subspicatus than UV irradiated 50 nm particles, which is in agreement with Hartmann et al. UV irradiated TiO₂ NPs also inactivated other algae species such as Anabaena, Microcystis, Melsoira and Chroococcus. It was demonstrated that smaller particles have a greater potential to penetrate the cell interior than submicron-sized particles and larger aggregates. Studies have shown that the amount of TiO₂ adsorbed on algal cells can be up to 2.3 times their own weight.