Clinical study of the bioavailability of 2 types of vitamin K2: MK-4 and MK-7 in healthy women



Comparison of menaquinone-4 and menaquinone-7 bioavailability in healthy women.



Vitamin K₂ contributes to bone and cardiovascular health. Therefore, two vitamin K₂ homologues, menaquinone-4 (MK-4) and menaquinone-7 (MK-7), have been used as nutrients by the food industry and as nutritional supplements to support bone and cardiovascular health. However, little is known about the bioavailability of nutritional MK-4. To investigate MK-4 and MK-7 bioavailability, nutritional doses were administered to healthy Japanese women.


Single dose administration of MK-4 (420 μg; 945 nmol) or MK-7 (420 μg; 647 nmol) was given in the morning together with standardized breakfast. MK-7 was well absorbed and reached maximal serum level at 6 h after intake and was detected up to 48 h after intake. MK-4 was not detectable in the serum of all subjects at any time point. Consecutive administration of MK-4 (60 μg; 135 nmol) or MK-7 (60 μg; 92 nmol) for 7 days demonstrated that MK-4 supplementation did not increase serum MK-4 levels. However, consecutive administration of MK-7 increased serum MK-7 levels significantly in all subjects.


We conclude that MK-4 present in food does not contribute to the vitamin K status as measured by serum vitamin K levels. MK-7, however significantly increases serum MK-7 levels and therefore may be of particular importance for extrahepatic tissues.

Published in the National Center for Biotechnology Information, under the auspices of the US Government.


  1. Chen, X., Furukawa, N., Jin, D. Y., Liu, Y., Stafford, D. W., Williams, C. M., … & Tie, J. K. (2022). Naturally occurring UBIAD1 mutations differentially affect menaquinone biosynthesis and vitamin K‐dependent carboxylation. The FEBS Journal, 289(9), 2613-2627.
  2. Ellis, J. L., Fu, X., Karl, J. P., Hernandez, C. J., Mason, J. B., DeBose-Boyd, R. A., & Booth, S. L. (2022). Multiple dietary vitamin K forms are converted to tissue menaquinone-4 in mice. The Journal of Nutrition, 152(4), 981-993.
  3. Knapen, M. H. J., Drummen, N. E., Smit, E., Vermeer, C., & Theuwissen, E. (2013). Three-year low-dose menaquinone-7 supplementation helps decrease bone loss in healthy postmenopausal women. Osteoporosis International, 24, 2499-2507.
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