It Ingredients.

Byline: editor: Sarah Brown

Catherine Piercy decodes beauty's new buzzwords and uncovers the five skin-care breakthroughs you need to know.

1. Niacin

Niacin, the active form of Vitamin B3, is earning a cult following among the seriously sun-damaged. One of its two skin-friendly incarnations, niacinamide, brightens dull skin and fades age spots in treatments like DDF DISCOLORATION REVERSAL-PODS. Pro-NAD--a unique, lipid-soluble form of the vitamin that may also reverse UV-induced DNA damage and has attracted the interest of the National Cancer Institute--appears in NIA 24 EYE REPAIR COMPLEX and CANYON RANCH YOUR TRANSFORMATION SERUM.

2. MMPi's

Matrix metalloproteinases (MMPs)--enzymes known to break down the skin's collagen and elastin tissue--are the latest focus of anti-aging power players. Gentle Waves, the LED light therapy wildly popular in derm offices, targets them successfully, but there's good news on the at-home front, too: A new class of MMP-inhibiting ingredients (called MMPi's) slows MMP activity when applied topically.

PATRICIA WEXLER, M.D. DERMATOLOGY MMPi.20 SKIN REGENERATING SERUM is packed with a potent soy complex; DR. BRANDT LINELESS CREAM also uses isoflavonoids from grape-seed extract. DERMALOGICA MULTIVITAMIN THERMAFOLIANT contains licorice-root extract and polyphenols from white tea. And because UV exposure also ups the production of MMPs in vulnerable skin, antioxidant-rich cocktails like SKINCEUTICALS PHLORETIN CF superserum offer extra protection.