Nourish your skin from the outside in: what's the best way to keep wrinkles at bay? Vitamins A, B, C, E, and K

Natural Health, Nov, 2004 by Karyn Repinski

WHAT TO EXPECT: There are no known side effects associated with the use of vitamin K, though some dermatologists warn that its benefits have not been thoroughly tested, so results may vary.

PRODUCTS TO TRY: Peter Thomas Roth Power K Eye Rescue ($100; sephora.com) harnesses the power of K to visibly brighten the appearance of dark circles, and includes the antioxidants green tea and vitamin C; and Quintessence Skin Science Clarifying Under-Eye Serum ($67; clickpharmacy.com), which contains both vitamin K and retinol, as well as green tea and vitamins C and E.

insider tip: Looking for a fix for under-eye circles? Find a product that has retinol as well as vitamin K. In a study published in the journal Cosmetic Dermatology, a cream containing both these nutrients caused a significant reduction in under-eye pigmentation after 16 weeks of daily use. Baumann suspects that the retinol may enhance K's ability to penetrate the skin.