Last verified: 17 days ago
Vitamin K2 (MK-4)
Also known as: Menaquinone-4, MK-4, Menatetrenone, Vitamin K2
Evidence under review. — Not yet rated
Fat-soluble vitamin that supports bone density and may help direct calcium to bones, not arteries.
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What it does
Vitamin K2 (MK-4) is a fat-soluble vitamin that activates proteins responsible for directing calcium to the right places in the body — primarily bones and teeth, rather than soft tissues like...
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Evidence quality
Evidence base hasn't been formally rated yet. See research below.
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Clinical dose
45 mg daily (Japan-approved dose for osteoporosis); lower doses (100-200 mcg) used in some cardiovascular studies
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Found in
What the Science Says
Vitamin K2 (MK-4) is a fat-soluble vitamin that activates proteins responsible for directing calcium to the right places in the body — primarily bones and teeth, rather than soft tissues like arteries. It works by carboxylating (activating) proteins like osteocalcin, which helps bind calcium into bone matrix. In Japan, a 45 mg daily dose of MK-4 is an approved pharmaceutical treatment for osteoporosis, though the evidence base for lower supplemental doses commonly sold in the West is less established.
What It Doesn't Do
Won't replace calcium or vitamin D — it works alongside them, not instead of them. No solid evidence it reverses existing arterial calcification. Low-dose supplements (45–200 mcg) are not the same as the high-dose pharmaceutical form studied for osteoporosis. Don't expect it to build bone on its own without adequate calcium intake.
Evidence-Based Benefits
Activates osteocalcin, a protein that helps bind calcium into bone and supports bone density.
Weak EvidenceEffective at: 45 mg daily (pharmaceutical); 100–200 mcg (supplemental, less studied)
Helps direct calcium toward bones and away from soft tissues like blood vessels.
Weak EvidenceEffective at: No established dose from provided studies
Absorption & Bioavailability
Moderate — MK-4 is fat-soluble and should be taken with a meal containing dietary fat for best absorption. It has a shorter half-life than longer-chain menaquinones like MK-7, meaning it clears the body faster.
Red Flags to Watch For
- Most consumer supplements use doses (45–200 mcg) far below the 45 mg pharmaceutical dose studied for osteoporosis — these are not equivalent
- Vitamin K2 can interfere with warfarin (blood thinners) — anyone on anticoagulants must consult a doctor before use
- Limited peer-reviewed abstracts were available for this analysis — claims should be interpreted cautiously
- MK-4 and MK-7 are often marketed interchangeably but have different half-lives and study profiles — check which form you're buying
Products Containing Vitamin K2 (MK-4)
See how Vitamin K2 (MK-4) is used in these analyzed products:
Frequently Asked Questions
What does Vitamin K2 (MK-4) do?
Fat-soluble vitamin that supports bone density and may help direct calcium to bones, not arteries.
What is the effective dose of Vitamin K2 (MK-4)?
45 mg daily (Japan-approved dose for osteoporosis); lower doses (100-200 mcg) used in some cardiovascular studies
Is Vitamin K2 (MK-4) safe?
Most consumer supplements use doses (45–200 mcg) far below the 45 mg pharmaceutical dose studied for osteoporosis — these are not equivalent
What doesn't Vitamin K2 (MK-4) do?
Won't replace calcium or vitamin D — it works alongside them, not instead of them.
Research Sources
- General knowledge
- Limited published research available — only one paper indexed with no available abstract
This information is for educational purposes only and is not medical advice. Always consult a healthcare professional before starting any supplement regimen. Last updated: 2026-05-25