Vitamin K2
Vitamin K contributes to normal blood clotting and the maintenance of normal bones.
Short answer Vitamin K contributes to normal blood clotting and the maintenance of normal bones. Adults need about 1 microgram per kilogram of body weight a day, which green vegetables supply. If you take warfarin, do not start vitamin K without medical advice.
K1 and K2
K1 comes from leafy greens; K2 from fermented foods and animal products. Supplements often pair K2 with vitamin D.
Is the pairing needed?
UK guidance does not ask for it. The evidence that K2 adds to vitamin D for bones is still developing.
Related pages
- Calcium supplementsAdults need 700mg of calcium a day, which dairy, fortified alternatives, bread and green vegetables usually cover.
- Zinc supplementsAdults need 9.5mg (men) or 7mg (women) of zinc a day.
- Folic acidAdults need 200 micrograms of folate a day.
- BiotinBiotin contributes to the maintenance of normal hair and skin.
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Questions people ask
What should I know about vitamin K2?
Vitamin K contributes to normal blood clotting and the maintenance of normal bones.
Can I take this with medication?
Ask a pharmacist or GP first; some supplements interact with medicines.
Do supplements replace a balanced diet?
No. They are meant to add to a varied diet, not stand in for one.
Sources
- NHS: Vitamins and minerals (opens in a new tab)
- Great Britain nutrition and health claims register (opens in a new tab)
Checked 9 October 2026.