Vitamin K1 is obtained in the diet primarily from dark leafy vegetables (lettuce, spinach, and broccoli). Unfortunately, vitamin K1 is tightly bound to the chlorophyll in green plants, thus, aging humans are not always able to benefit from ingested K1-containing plants. While vitamin K1 is not absorbed particularly well from food, it is absorbed from supplements, provided that the supplements are taken with meals.

Vitamin K2 (menaquinones) is found in meat, eggs, and dairy products and also made by bacteria in the human gut, which provides a certain amount of the human vitamin K requirement. Human studies show that vitamin K2 is absorbed up to ten times more than K1. Vitamin K2 remains biologically active in the body far longer than K1. For instance, K1 is rapidly cleared by the liver within eight hours, whereas measurable levels of K2 have been detected 72 hours after ingestion.2

Super K provides vitamin K1, and two forms of vitamin K2 known as menaquinone-4 and menaquinone-7. The menaquinone-7 form of vitamin K is not metabolized quickly by the liver, thereby making it available to provide a more consistent supply of vitamin K to the body.