Vitamin K2

The vitamin that helps direct calcium into bone.

Also known as: Menaquinone-7, MK-7
Evidence: Clinical evidence Evidence level 4 of 5
Key compounds: Menaquinone-7 (MK-7), a long-acting form of vitamin K2.
Body systems: Bones

In research

K2 activates proteins such as osteocalcin and matrix Gla protein, which are involved in where calcium is deposited in the body.

Strength of evidence

Clinical evidence

Tested in randomised trials in people, usually small or short. How we grade evidence.

What we know

Activates proteins that bind calcium into bone. A three-year trial slowed bone density loss in postmenopausal women.

What we do not know yet

Whether it reduces fractures or protects arteries in people.

Safety and cautions

Interacts with warfarin and other vitamin K antagonists. Anyone taking these must speak to their doctor first.

Evidence

Research and answers

Appraised research and plain-language answers that involve Vitamin K2.

Randomised controlled trial Supportive

Menaquinone-7 and bone loss after menopause

A plausible mechanism with a supportive trial on bone density. Fracture benefit remains unproven. People taking warfarin should not take vitamin K without medical advice.

Osteoporosis International, 2013 · 244 participants · Vitamin K2

QuestionBones

Do I need a vitamin D supplement?

Only if you are low, or at risk of being low. A very large trial found that giving vitamin D to generally healthy adults who were not deficient did not reduce fractures.

Myth or evidenceBones

Calcium alone builds strong bones

Calcium is the raw material, but bone strength depends on much more: vitamin D to absorb it, vitamin K2 and protein to build it into bone, hormones and, above all, weight-bearing activity that tells bone to grow stronger.

Where you will find it

Products that contain it

Ceptomin-KO Calcium, with the partners it needs. Tablet · 45 mcg

Often found alongside

The full atlas

CalciumMineral FolateVitamin LycopeneNutrient Omega-3 fatty acidsNutrient Vitamin B12Vitamin Vitamin B6Vitamin

Ingredient pages summarise traditional use and the direction of published research for education. They are not claims about any product and are not medical advice.

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