Life Extension Super K with Advanced K2 Complex formula provides vitamin K1 and the MK-4 and MK-7 forms of vitamin K2 in just one daily softgel. This formula offers the precise amount of the long-acting MK-7 form of vitamin K2 that recent human studies have shown provides optimal K2 levels over a 24-hour period. The MK-4 is included to provide a rapid increase in vitamin K blood levels, which may account for its beneficial effects in certain studies. Vitamin K2 has been extensively researched, revealing vastly improved effects compared to K1.