Many of the most prized synthetic skincare ingredients do occur naturally but for various reasons are reproduced in a lab. Take peptides, which are commonly considered the most valuable ingredients for cell regeneration. “They might not exist without synthetics,” says Dr. Daniel Stangl, director of innovation for La Prairie. “Peptides are a complex chain of amino acids, and the order determines their efficacy. It’s hard to get peptides in a precise sequence from natural sources, and if you do find them they usually are not present in high concentrations.”