While there is a lot of debate regarding natural and chemical sunscreens, what most people are referring to are the differences between mineral and chemical sunscreens. To add to the confusion, mineral sunscreens are also referred to as physical blockers. “Chemical and mineral sunscreens are differentiated by their active sun-protection ingredients,” says Chris Birchby, CEO of Coola. Mineral sunscreens most often rely on ingredients such as titanium dioxide and zinc oxide, which form a barrier against the sun’s rays.
According to Cyberderm’s Denis Dudley, the terminology used to differentiate between the two types of sunscreen can be misleading. “The word natural, meant to imply non-chemical, is a misnomer, as all UV filters are chemicals,” says Dudley. He prefers to think of them as soluble (chemical) or insoluble (mineral).
Regardless of what you call them, when choosing between the two types, it’s important to keep in mind that chemical sunscreens need to be applied at least 30 minutes before sun exposure, whereas mineral sunscreens are effective upon application. “Chemical active sunscreens can break down over time and with a lot of exposure to the sun, rendering them less effective,” says Birchby. “This is one of the reasons why the Skin Cancer Foundation and FDA recommend reapplying sunscreen every two hours. Mineral active sunscreens don’t break down while working like chemical actives, but like all sunscreens, they can rub and be sweated off and should also be reapplied every two hours and after swimming.” Some chemical sunscreens get a bad rap, because they can mimic hormones, accumulate in the blood, and cause skin allergies. However, they can be easier to apply and are frequently paired with antioxidants and other skin-nourishing ingredients.
Although mineral sunscreens often have a longer shelf life and are less likely to clog pores or irritate sensitive skin, they may appear chalky, especially on darker skintones. “In order to provide coverage at SPF 50, for example, one has to go beyond a purely zinc formula unless you want the application to appear white and chalky,” says Dawn Clifford, senior director of education at Image Skincare. “It’s simply a balance of using safe, clinically tested ingredients to allow for an elegant application.”
Read more: The Truth About Different Levels of SPF