Manufacturers of vitamin K skin creams claim that vitamin K can diminish under-eye circles, fade bruises and lessen the appearance of skin redness and discoloration. Because vitamin K can interact with the circulatory system and affect the blood's ability to clot, cosmetics manufacturers claim it may calm vein-related skincare issues such as spider veins and rosacea.
In the United States, the Food and Drug Administration classifies vitamin K as a cosmetic ingredient in skincare. Because of this, manufacturers do not need to provide clinical proof of the benefits of the vitamin as an ingredient in skin cream. Studies on vitamin K show the vitamin must be taken internally and metabolized by the liver to have a significant effect on clotting. The body receives a far smaller dose of vitamin K in skin cream, which greatly lessens the vitamin's intended effect on veins and blood flow.
As of December 2015, the skincare ingredient directory at Paula's Choice notes that several studies involving vitamin K creams have shown moderately positive results when test subjects applied the creams to under-eye circles or post-laser redness. However, the studies did not address the possible effects of other ingredients in the creams, and they did not test the effect of vitamin K against the possible effects of other vitamins and antioxidants, such as vitamin C, on the same kinds of flaws.