Zinc Oxide and Titanium Dioxide are the only ingredients approved by the FDA to give your sunscreen a natural SPF. Zinc oxide and titanium dioxide are minerals, naturally found in the earth. Once they get into your sunscreen, though, they have been processed and refined.
Natural sunscreens work differently than chemical sunscreens. Synthetic sunscreen ingredients absorb UV rays. Zinc oxide and titanium dioxide, on the other hand, are physical sunscreens. They don't absorb UV rays, they block them. It's like having little "shields" over your skin protecting you from sun exposure.
There's some indication that using physical sunscreens long-term give you better protection against photoaging because, unlike synthetic sunscreens, there is no chemical reaction occurring on your skin.
Source: https://www.verywellhealth.com/how-to-choose-a-nat...