Vitamin KWhat is vitamin K?
Updated 3 Nov 2026
Short answer
Vitamin K is a group of fat-soluble vitamins. Vitamin K1 (phylloquinone) comes mostly from green leafy vegetables and is the main form in food. Vitamin K2 (menaquinones, such as MK-4 and MK-7) comes from fermented foods, and in small amounts from meat, dairy foods and eggs. Bacteria in the gut also make it.[1]
The body needs vitamin K to make clotting proteins and some proteins of bone.[1] Supplements contain vitamin K1 or vitamin K2 as MK-4 or MK-7.[1]
Sources (1)
- Vitamin K: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements. ods.od.nih.gov
More about vitamin k
Which foods contain vitamin K?What is vitamin K used for?Who is at risk of vitamin K deficiency?Is vitamin K safe?Why do newborn babies get vitamin K?Does vitamin K help keep bones strong?For education; not medical advice. Talk to a doctor before you start, stop or change a supplement.