From a toxicological perspective, physical sunscreens are generally recognized as safe when used as directed. Zinc oxide and titanium dioxide are not absorbed in significant amounts through the skin, which minimizes systemic exposure. However, the safety of these ingredients in nanoparticle form has been a subject of scientific scrutiny. Current evidence suggests that nanoparticles remain on the skin's surface and do not penetrate into deeper layers, thus posing minimal risk.
