Biologique Recherche Lotion P50 is something of a skin-care legend for its ability to shrink pores, slough off dead skin, clear up acne, and make skin feel freakishly soft in a matter of days. “It’s often someone’s first experience with acid exfoliation, and that’s a special moment when you feel the tingle and see your skin smoother the very next day,” Mattioli says. “Over time, your skin gets even smoother, brighter, and clearer.” There are five versions, but P50 1970, which contains a controversial E.U.-banned exfoliator called phenol (and makes your face go numb), is the most intense. “Phenol gets demonized, but dermatologists have historically done phenol peels in very high concentrations,” Engelman says. “I’m not scared of phenol; I’m a fan of it.” One thing to note: It isn’t uncommon to look a little red/sunburned as your skin adjusts to P50. For me it usually lasts about a week, but you can temper it by watering it down; just soak your cotton pad with water before dabbing it with the toner.