Scientists still don't have complete answers about whether nanoparticles in cosmetics are safe—despite 20 years of research. The good news: researchers have identified ways to make nanoparticles less toxic. The reality: we're not there yet, and the safety picture depends heavily on which nanoparticles are used and how.

This was a comprehensive review article that synthesized existing research on nanoparticle toxicity, how they interact with human cells, and current safety-reduction strategies across cosmetics, drug delivery, and diagnostics.

Funding not disclosed in abstract