What is Vitamin K2?
A fat-soluble vitamin that directs calcium to bones rather than arteries.
Vitamin K2 (menaquinone) activates proteins that regulate calcium metabolism. It helps ensure calcium is deposited in bones and teeth rather than soft tissues like arteries. MK-7 is the preferred form due to longer half-life.
What the evidence says
The overall evidence grade for Vitamin K2 is B (moderate — mixed or smaller trials, reasonable mechanistic support). Mechanistic understanding is strong. Clinical outcomes data is growing but not as robust as for D3.
Specific findings with supporting evidence:
- Activates proteins for calcium metabolism. Evidence grade A.
- Supports bone mineral density. Evidence grade B.
- May support arterial health. Evidence grade B.
Best-supported outcomes:
- Calcium utilization.
- Bone support.
- Potential cardiovascular support.
Where marketing outpaces evidence:
- Marketing often overstates: Reverses arterial calcification.
- Marketing often overstates: Substitute for statins.
Dose and timing
The typical effective dose for Vitamin K2 is 100–200 mcg. MK-7 form preferred.
Take it in the morning and afternoon with a fat-containing meal. Fat-soluble; pair with D3.
Who it's for, and who should skip it
Most relevant for:
- Those taking vitamin D3.
- People concerned about calcium metabolism.
- Those with cardiovascular concerns.
Not appropriate for:
- Those on warfarin without medical guidance.
Safety and cautions
Important: Warfarin interaction. K2 can interfere with warfarin; consult provider.
Common mistakes
- Taking K1 instead of K2.
- Not pairing with D3.
- Taking with warfarin without guidance.
Myths vs reality
A common misconception: K1 and K2 are interchangeable. In reality, k1 is for clotting; K2 specifically regulates calcium.
How it interacts with other compounds
- Vitamin K2 works well alongside vitamin d — k2 optimizes D3 calcium effects.
- Vitamin K2 works well alongside calcium — k2 directs calcium properly.
Questions people ask
MK-4 vs MK-7? MK-7 has a longer half-life and requires lower doses for effect.
Editorial note
This guide summarizes the published evidence on Vitamin K2. It is educational content, not medical advice. Confirm with your clinician if you take prescription medications or manage a chronic condition.