They use a retinoid cream every night.
"The first time I meet someone, I immediately know if she's using a retinoid because her skin is glowy and smooth," says Miami dermatologist Leslie Baumann, MD. Retinoids are vitamin A derivatives that have been proven to boost collagen, which reduces fine lines, and to speed cell turnover, which evens out discoloration. Retinoids are available over-the-counter (as retinol) or with a prescription (as tretinoin, adapalene, and tazarotene). Because retinoids can cause some irritation at first, Hirsch recommends applying a gentle moisturizer, letting it soak in for at least 30 minutes, then applying your retinoid cream.