well in my case it did nothing lol but i bought a special cream in the drgustore that was specifically for the under eye circs that was main ingred vit. k.
"Vitamin K supports the capillary system of the skin, helping reduce dark undereye circles,
bruising, spider veins, Rosacea, and broken capillaries."
" When the fat pad beneath the eye begins to thin with age, it can create a sunken look to the under eye area. Studies have shown that sluggishness of blood flow underneath the eyes may also contribute to dark circles. Vitamin K has been found to diminish the appearance of these dark circles.
If patients feel that concealers for the under eye area are no longer covering their circles, they should look for under eye skin treatments that contain vitamin K."
http://www.makeupartistschoice.com/vitamink.htm