Metals from certain sunscreens can stay in the blood stream for up to 23 hours at levels higher than recommended by the U.S. Food and Drug Administration.
That's according to a new study published Tuesday by the Center for Drug Evaluation and Research, an arm of the FDA.
Researchers used four commercially available sunscreen products including lotion, aerosol spray, non-aerosol spray and pump spray.
They found that even a single sunscreen application results in measurable blood levels of the active ingredient.
"The fact that an ingredient is absorbed through the skin and into the body does not mean that the ingredient is unsafe," said Janet Woodcock, M.D., director of the Center for Drug Evaluation and Research.
Woodcock says further industry testing is needed to determine the safety and effects of systemic exposure of sunscreen ingredients.
Experts also say it's still better to put suntan lotions on, than none at all.