It wasn’t long after Sigma Beauty’s 2009 launch that the brand became a favorite among beauty insiders. And it’s no wonder. Founded by a civil engineer and a researcher with a Ph.D. in molecular biology, everything in Sigma Beauty’s collection—from hypoallergenic makeup brushes to pro-quality makeup—is created with innovation in mind. The result? High-performance products adored by editors at W, Harper’s Bazaar, InStyle, and, of course, Birchbox.