Neil Sadick, MD
Clinical professor of dermatology at New York Presbyterian Hospital/Weill Cornell Medical Center
Sadick Dermatology Group PM Reversal Serum
"To get younger-looking skin, you need to build collagen, stimulate elastin, and encourage cell turnover. This serum does all three—with retinol, peptides, and two different alpha hydroxy acids."
Obagi Professional-C Serum
from $48; lovelyskin.com
"Vitamin C is a great complexion-protecting antioxidant—when it's potent and stable, as it is in this formula. It can also be irritating, so I like that this serum comes in several concentrations—I start patients at 5 percent and work up to 20."