It sounds like they got some commercially available chemical sunscreens and added zinc oxide, which caused a reaction in those components, increasing their toxicity. That seems bad, but in my experience, zinc oxide is used in lieu of chemical components, not in addition to them. I'm not clear this interpretation is correct because the article only mentions zinc oxide, not the components which reacted to it.
Yeah the study has that major flaw. There are actually a lot of chemical sunscreens where they throw in a few % of zinc oxide for whatever reason, so it’s important to study but these aren’t billed as “natural” or safer. it’s a very flawed study not to test the pure mineral sunscreens.
It's not even clear that they did that. It sounds like they made their own sunscreens from the ingredients commonly found in some sunscreens and then added the zinc oxide to test what would happen.
