Your brows should be sisters, not twins, but even your arches can experience a little bit of sibling rivalry. A little bit of eyebrow pencil, gel, or powder is the easiest way to spark a truce. However, there’s more to ending the clash then just grabbing whatever brow product you might have in your beauty stash. It’s actually all about which shade you’re using. N.Y.C. aesthetician Piret Aava, a self-proclaimed eyebrow doctor says that choosing the right shade to fill in your brows has more to do with your complexion than with the hair on your head. To cut out the guesswork, we had her spill her color theory. Here, we have your go-to guide on the shade you should be using to fill in your brows for the most inconspicuous finish.