Vitamin K2 (MK-4)
Also known as: Menaquinone-4, MK-4, Menatetrenone, Vitamin K2
Effective Dosage
45 mg/day (pharmacological, Japan); 100-200 mcg/day (nutritional)
What the Science Says
Vitamin K2 (MK-4) is a fat-soluble vitamin that activates proteins responsible for calcium regulation in the body. It activates osteocalcin, a protein that helps bind calcium into bone tissue, and activates Matrix Gla Protein (MGP), which helps prevent calcium from depositing in arteries and soft tissues. Japan has used pharmacological doses (45 mg/day) as a prescription treatment for osteoporosis, though nutritional supplement doses are far lower and the evidence base for those lower doses is limited.
What It Doesn't Do
Won't replace calcium or vitamin D — all three work together and none substitutes for the others. No strong evidence it reverses existing arterial calcification in humans. Not a proven heart disease treatment. High-dose MK-4 results from Japan don't automatically apply to the low-dose supplements sold in most Western markets. Won't build bone on its own without adequate calcium intake.
Evidence-Based Benefits
Vitamin K2 (MK-4) is a form of vitamin K that plays a role in calcium metabolism and bone health. Some preliminary studies suggest it may contribute to improved bone density and cardiovascular health, but the evidence is very limited and not well-established.
Weak EvidenceEffective at: Unknown (insufficient research data)
Source: auto-research
Absorption & Bioavailability
Moderate — MK-4 is fat-soluble and should be taken with a meal containing dietary fat for best absorption. It has a relatively short half-life compared to longer-chain menaquinones like MK-7, meaning it clears the body faster and may require more frequent dosing.
Red Flags to Watch For
- MK-4 interacts with warfarin (Coumadin) and other blood thinners — do not supplement without medical supervision if on anticoagulants
- Pharmacological doses used in Japanese osteoporosis trials (45 mg) are roughly 450x higher than typical nutritional supplement doses (100 mcg) — marketing often conflates these very different dose levels
- Limited published research was available for this analysis — most evidence comes from general scientific knowledge, not the provided study abstracts
- Supplements vary widely in dose and form; MK-4 and MK-7 are often marketed interchangeably but have different pharmacokinetics and evidence profiles
Products Containing Vitamin K2 (MK-4)
See how Vitamin K2 (MK-4) is used in these analyzed products:
Research Sources
- General knowledge
- Limited published research available
This information is for educational purposes only and is not medical advice. Always consult a healthcare professional before starting any supplement regimen. Last updated: 2026-04-06