Jeff, can you point to a study? I’ve seen many people make the claim you need at least 20% zinc oxide to provide good sun protection, but oddly enough, no one ever mentioned a source!

It’s not just the concentration that determines how well zinc oxide protects from you UV rays. Size matters, too. Zinc oxide comes in many sizes and each one works better at different %. Also, you need to formulate in a day that disperses properly on the skin. And don’t forget that other filters in the formula count towards the overall SPF rating, too.

So, it’s totally possible to formulate an effective sunscreen with a smaller concentration of zinc oxide. As long as the brand has done the testing to prove the sunscreen provides the SPF stated on the bottle, I don’t have a problem with it.

If you find a study that claims the contrary, I’d be interested in it. For now, I find it interested that “zinc oxide is effective only at 20%” claims come from companies that use that much. And their sunscreens are incredibly thick and white as a result.

Rachel, which EltaMD sunscreen? the main difference is the antioxidants. EltaMD sunscreens are pretty basic and just sun protect and moisturise. This has a few antioxidants that can boost your sun protection further.

JD, you’re spot on!