Here's the deal: Ingredients like titanium dioxide and zinc have large particles that tend to sit on top of the skin and give it a noticeably ashy cast, says Dr. Wu. Find sunscreens with Helioplex or Mexoryl, finer UV-protecting compounds that blend in well on darker skin tones, says Great Neck, N.Y., dermatologist Jeannette Graf. One option: this thin liquid formula from Neutrogena.
Neutrogena Ultra Sheer liquid sunblock fluid SPF 70, $13/1.4 oz.; at drugstores.Read MoreLess