Even with hundreds of SPFs out there, the lot can be boiled down to two categories: chemical sunscreens and physical sunscreens.
But what formula is best for sensitive skin -- or overall? In the video above, NYC-based dermatologist Dr. David Colbert, who treats Rosie Huntington-Whiteley, boils down the differences between the two, plus how often you need to reapply.
Diane Kruger applies sunscreen during the French Open Tennis tournament in Paris, France on May 31, 2012.
In terms of what the stars are using, Selma Blair chooses a physical formula for her and her son Arthur, 10 months. "I'm green!" the actress has explained to Us. Meanwhile, Jennifer Lopez uses L'Oreal Paris Sublime Sun SPF 50+ on both her and her "little coconuts," twins Max and Emme. In the pic above, Diane Kruger douses herself with Neutrogena's aerosol formula.
Tell Us: What is your favorite sunscreen?