When Natalia Guzman, FNP-C, CANS considered which treatments she wanted to offer at Atelier Aesthetix, her new med spa in Beverly Hills, California, she kept a guiding principle in mind: she’d only offer treatments she truly believed in. Forget procedures with lots of buzz but no research-based results to back them up: to a pro with deep integrity like Guzman, belief is no abstract thing. She pores over the data around each procedure, examines its results up close, and considers whether it’s truly the right fit for her clientele. Guzman has always brought this exceptional attention to detail to her work. She grew up in El Salvador and move...