What to Know: When it comes to sunscreen efficacy, application matters immensely. Physical sunscreens are effective immediately upon application, while chemical ones require at least 20 minutes to fully absorb; that means always plan to apply before getting dressed to ensure full coverage (arms, shoulders) and ample time for absorption..
What to Do: For the body, allot at least a shot-glass-size portion of sunscreen and, for the face, a tablespoon. Reapply every two hours (more if you’re swimming or sweating). “Chemical blockers lose their effect as they continue to react to sunlight, and physical blockers will clump,” explains Zeichner.
What’s Right for You: The type of sunscreen you use (cream, spray, stick) will impact how you apply it. “On the body, sprays should be held one to two inches from the skin, sprayed until the area glistens and then rubbed in,” says Zeichner. “Sticks should be applied back and forth for four passes on the same area.” Because creams tend to be a bit thicker than sprays Jaliman advises starting with the former and using the latter for reapplication. “And never ever spray sunscreen directly on your face; spray it in your hand then apply to face,” she adds.