Menaquinone (vitamin K2)

Menaquinone (vitamin K2) is a form of vitamin K often promoted as a supplement for anti-aging and longevity. Clear benefit for this use has not been shown: there is no solid evidence that K2 extends lifespan or slows aging. Lifespan responds far more to managing blood pressure and blood sugar, not smoking, staying physically active, and sleeping well – worth discussing with your doctor. Important: vitamin K reduces the effect of warfarin and other vitamin K antagonists; patients on these anticoagulants, including those with a mechanical heart valve, must not take vitamin K supplements without medical agreement.

Menaquinone (vitamin K2) is a fat-soluble vitamin involved in calcium metabolism. It's promoted as a supplement to prevent vascular calcification, with the idea that K2 routes calcium into bone rather than the artery wall. So far this use hasn't shown convincing benefit – there's no solid evidence that taking K2 reduces vascular calcification or cardiovascular risk. The substance itself is harmless at these doses. What actually lowers vascular calcification is managing blood pressure, lipids and blood sugar, quitting smoking and staying physically active – worth discussing with your doctor. Don't take menaquinone in place of treatment with proven benefit, since that risks missing the care you need. Important: vitamin K reduces the effect of warfarin and other vitamin K antagonists; patients on these anticoagulants, including those with a mechanical heart valve, must not take vitamin K supplements without medical agreement.

EFSA 2009 approved the claim “vitamin K contributes to bone health maintenance” for labelling. Evidence on oral K2 in postmenopausal osteoporosis is limited: the 2008 Booth RCT did not show a significant effect on bone mineral density or fractures. Endocrine Society 2019 does not include K2 in osteoporosis treatment standards. Standard therapy: bisphosphonates, denosumab, teriparatide + calcium + vitamin D. Important: vitamin K reduces the effect of warfarin and other vitamin K antagonists; patients on these anticoagulants, including those with a mechanical heart valve, must not take vitamin K supplements without medical agreement.

Japanese guidelines for postmenopausal osteoporosis include MK-4 at 45 mg daily, but this is a narrow local practice not supported by international consensus.