[header] How to choose a natural sunscreen [title] Look for 10 percent zinc oxide or titanium dioxide. [step] Natural sunscreens often use ingredients that physically, rather than chemically, block the sun. Because these don't offer a high spf on their own, you need to make sure they have a high enough concentration in the sunscreen to actually block the sun's uv rays. 
Choose a sunscreen that has a 10 percent or higher concentration of zinc oxide or titanium dioxide. [substeps] These two ingredients are the only fda-approved ingredients for blocking the sun that are often used in natural sunscreens.