Titanium dioxide: uses, toxicity and conflicting lab results
What it found
Titanium dioxide is used in food, sunscreen and water treatment, but studies disagree about its health effects.
The authors say lab tests on its toxicity are hard to compare because methods differ.
What they found
Studies in people
Human lung exposure
A large study on human lung exposure found no link between workplace exposure to titanium dioxide and lung cancer. The authors note that animal studies often use extreme conditions that do not match real human exposure.
Animal and lab studies
Animal and cell studies
In rodents, high doses of titanium dioxide caused inflammation in the stomach and intestine, liver cell death, heart tissue damage, anxiety-like behaviour, colon tumours and kidney damage. In human intestinal cells, food-grade titanium dioxide showed only moderate DNA-damaging effects.
Conflicting lab results
Common lab tests for cell damage give inconsistent results with titanium dioxide because its light-absorbing properties interfere with the measurements. This can lead to false-positive or false-negative results.
Other findings
Structure and light
Titanium dioxide comes in three crystal forms: rutile, anatase and brookite. Rutile scatters light best, while anatase absorbs ultraviolet light more strongly.
Water and food treatment
Under ultraviolet light, titanium dioxide can break down chemical pollutants, warfare agents and microbes in water. It is also used in food packaging to keep food fresh by breaking down ethylene and killing microbes on the surface.
Sunscreen use
Titanium dioxide scatters ultraviolet light and is used in sun creams. Coating it with silica or other inert materials can reduce its unwanted chemical reactions while keeping its light-scattering effect.
Food additive E171
In food, titanium dioxide is known as E171 in the European Union and INS171 in the United States. It adds whiteness and opacity to foods like creamers, fish, instant drinks and confectionery, but has no nutritional value.
What the authors conclude
“The standpoint of the author is that joint scientific efforts are required to ascertain the mechanisms of titanium dioxide toxicity, as this influences all the abovementioned uses and breakthroughs.”
Also in their conclusions
- They say that a balance is needed between using tiny titanium dioxide particles as an anticancer agent and their potential harm to healthy cells.
- They advise that authorities should raise public awareness about E171 in food while they work out its potential to cause mutations.
- They call for joint scientific efforts to pin down how titanium dioxide causes harm, because this affects all its uses.
How it was done
The authors wanted to review the latest advances in industries that use titanium dioxide, while addressing concerns about its disputed toxicity.
They reviewed published research on titanium dioxide's structure, optical properties, and uses in water decontamination, sunscreen, food packaging and food processing. They also examined studies on its toxicity in animals, human cells and people, and looked at why results differ between labs.
What it can’t tell you
- Many of the harm findings come from animal or cell studies, so they cannot show what happens in people.
- The review cannot say whether titanium dioxide causes cancer in people, because human data are limited and lab tests give conflicting results.
- It is not possible to set a daily intake limit for E171 from this paper, because the authors say a threshold cannot be determined for a substance that might damage DNA.
Who paid
- Conflicts
- The author declares no conflict of interest.
- Authors work at
- University of Warwick, UK
The paper
- Title
- Titanium Dioxide: Structure, Impact, and Toxicity
- Type
- ReviewThe authors read earlier studies and describe what they found. It isn’t a new study.
- Evidence
- Studies in people · animals · lab
- Summarised from
- Full text
- Cite
- Racovita AD (2022). Titanium Dioxide: Structure, Impact, and Toxicity. International journal of environmental research and public health. doi:10.3390/ijerph19095681Free full textPubMed 35565075DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error