Dyeing hair darker to look younger?

Try for A touch of shine instead.
Yes, even if you're grey. In fact, that four-letter color can look edgy on the right person, especially with a few blond highlights, says Terrence Michael Renk, a stylist at J Beverly HIlls who works in TV and film. "More important than dyeing," he says, "is the texture: Young hair is shiny, and that gets lost when we age." Renk loves to glisten things up with glazes—clear or in warm demi-colors.
Also the cut and a few well-placed highlights can counter facial sagging, he says. "And have some fun. One of the biggest trends right now is the 70s influence. There is nothing wrong with a 50-year-old woman putting a braid on one side of her head. "