Titanium dioxide particles help light scatter and reflect, Kelly Johnson-Arbor, MD, a medical toxicology physician at the National Capital Poison Center, told Health. Because of that, we often use it as a whitening agent.

But a chemical’s safety when it’s used externally is not always the same as when it’s ingested. Different uses of the same ingredient may cause very different health outcomes.

Production

The whole scientific experimental design in some of these studies is‌ very flawed, Kaminski said.