The ABCs of vitamins for more beautiful skin

Vitamin A: best overall age fighter
Find it in OTC lotions, night creams (vitamin A derivatives are known as retinoids), and prescription products.
Proven to: reduce wrinkles, fade brown spots, and smooth roughness.

Vitamin B3: boosts hydration to reduce redness
Find it in lotions, creams, and serums. It's often called niacinamide on the label.
Proven to: increase production of ceramides and fatty acids, two key components of your skin's outer protective barrier.

Vitamin C: all-around anti-ager
Find it in moisturizers formulated to keep vitamin C stable (opaque, airtight containers are ideal). Look for C near the middle of the ingredients panel to help ensure the 5 percent or higher concentration needed to see benefits.
Proven to: mop up the free radicals that trigger wrinkling, sagging, and other aging changes. Vitamin C also helps smooth and firm skin and fade brown spots.

Vitamin E: eases dryness and bolsters skin’s UV defense
Find it in sunscreens and after-sun products. The best products contain at least 1 percent vitamin E, so it will be listed near the middle of the ingredients panel.
Proven to: quell dryness by helping skin retain its natural moisturizers. Also, vitamin E's potent ability to neutralize damaging free radicals has earned it the moniker "the protector."

Vitamin K: for younger, brighter eyes
Find it in eye creams that also contain retinol.
Proven to: possibly help lighten under-eye circles. Fragile capillaries that allow blood to leak into skin are considered one cause of under-eye circles, and vitamin K (aka phytonadione) may put the skids on this by controlling blood clotting. Daily use of a K cream significantly lightened circles after 4 months in one study, but because the cream also contained retinol, researchers aren't sure which ingredient deserves credit for the improvement — retinol alone thickens the translucent under-eye skin (making it harder to see the dark blood vessels below) and lightens melanin that makes circles more prominent. Still, it can't hurt to try a cream that contains vitamin K and retinol.