Circulating vitamin K concentrations following a single oral dose of 1 mg each of vitamin K1 and MK-7. Points are means from 15 subjects; error bars represent SD. Baseline levels (1 nM [0.45 μg/L] for K1 and < 0.07 nM [< 0.05 μg/L] for MK-7) were subtracted from all values. ▪ indicates K1; and ○, MK-7.