NEGIN MIRSALEHI

29, NETHERLANDS COFOUNDER GISOU

Two years ago social-media star Mirsalehi turned down $800,000 for a brand ambassadorship with a major hair-care line. she had bigger plans: she self-funded and now runs gisou, a maker of haircare products, like a honey-infused hair oil, inspired by her family’s long history as beekeepers.