Zinc Oxide Sunscreen Safety

Wearing sunscreen helps ward off everything from premature aging to skin cancer, but it's also important that sunscreen ingredients themselves not cause harm. Scientists have studied the safety of zinc oxide, an active ingredient in many sunscreens.

Blocking Action

According to the Australian government's Therapeutic Goods Administration (TGA), zinc oxide is favored for use in sunscreens because it blocks not only UVA but UVB rays as well.

Nanoparticles

Because traditional zinc oxide formulations leave a white residue on the skin, sunscreen manufacturers began to offer sunscreens formulated with zinc oxide nanoparticles, because the residue is less noticeable.

Safety Concern

Scientists were called on to respond to concerns that these nanoparticles might penetrate viable skin cells, interact with sunlight while inside the cells, and damage the cells.

Safety Assessment

After reviewing the relevant scientific literature, the TGA concluded in early 2009 that zinc oxide nanoparticles appear to stay within the outer layer of skin, where there are no viable cells that could be damaged. Future studies may have different findings, however.

Product Labeling

It can be difficult to tell whether a zinc oxide sunscreen has been formulated using nanoparticles since, even when ingredients are listed, particle sizes may not be.

References

• Australian Government's Therapeutic Goods Administration: TGA Fact Sheet, Sunscreens