Yep, it could help relieve dark circles under eye area. In fact, dark under-eye circles could be caused by various reasons, but the essential one is poor blood flow. And there is more melanin production in subjects with that. Vitamin K could be mainly found in green leafy vegetables, meats, fish. It has the function of blood clotting proteins to keep blood flow, and has the function of Gas6, a specialized protein that regulates cell growth and cell proliferation. Hence, vitamin K could benefit for treating dark circles under the eye area. However, it is an essential vitamin, not the only vitamin is needed for treating dark circles.