Dose-response curves for K₁ and MK-7 at 4 and 24 hours following a single oral dose. (A) Curves for K₁; (B) curves for MK-7. Points are means from 10 volunteers; error bars represent SD. The difference between K₁ and MK-7 at 4 hours was statistically significant at doses of at least 150 μg; at 24 hours the difference was significant at all doses. • indicates serum vitamin K concentrations at 4 hours; and ○, serum vitamin K concentrations at 24 hours after mealtime.