Star power: A synthetic version of the skin-plumping, joint-lubricating substance produced naturally in our bodies—actually a sugar—the hyaluronic acid in skincare products is a terrifically effective humectant. "It draws a tremendous amount of water to the skin—about 1,000 times its weight," says cosmetic chemist Randy Schueller, editor in chief of thebeautybrains.com. Hyaluronic acid not only makes parched skin feel better but also temporarily plumps it, and is light enough to blend seamlessly with makeup.
What to look for on the label: Hyaluronic acid, hyaluronan and sodium hyaluronate.
For best results: Use liberally wherever your skin is dry and needs hydrating. Hyaluronic acid isn't irritating and won't interact negatively with, or compromise the effectiveness of, other skincare ingredients you might be using.
You should know: To smooth very dry skin, you'll need more than hyaluronic acid alone. Start by applying a hyaluronic acid serum or light lotion on clean skin, then top it with a rich moisturizer in a lotion or a cream that contains ceramides (moisture-retaining lipids).
Dior Hydra Life Pro-Youth Sorbet Eye Crème ($49; dior.com)
Dr. Jart+ Water Fuse Beauty Balm SPF 25 PA++ ($34; sephora.com)