Serum cocktailing — or "stacking individual ingredients that are purchased separately and believing that is the equivalent of one product that contains multiple of them together" — as board-certified dermatologist Kavita Mariwalla called it is a risky move. That's why dermatologists recommend saving your mixology skills for the kitchen.
Here's why: "Ingredients are only one part of the formulation," said Dr. Mariwalla. "You have to think about stability, percentages, and how it is manufactured. Consider simplifying your routine and using one or two products that have actives combined — often those formulations are actually more clinically active than the ingredients alone."