In Your 30s
Keep doing what you were doing in your 20sfor your skin-care regimen, that is. But in your early 30s, you'll want to add an over-the-counter retinol to promote collagen production, says Dr. Tina Alster, director of the Washington Institute of Dermatologic Laser Surgery. At first, put the product on every other night, on top of your antioxidant serum. If this doesn't irritate your skin, work up to nightly use.
Neutrogena Rapid Wrinkle Repair Night, $21; neutrogena.com