With A-list clients like Chrissy Teigen, Kim Kardashian, Kendall and Kylie Jenner, and Gigi and Bella Hadid, to name a few, and millions of followers on social media, it’s no wonder The New York Times dubbed Jen Atkin “the most influential hairstylist in the world.” As the founder of haircare line OUAI, she knows her way around creating beloved products. Now she's brought her beauty insider knowledge to e.l.f.