A 2-year Dutch randomized trial found that 360 μg/day of vitamin K2 (MK-7) modestly slowed the buildup of coronary artery calcium in patients with established symptomatic heart disease. The effect was statistically real but small, and it did not change how many patients were classed as “fast progressors.”
Calcium in the coronary arteries is one of cardiology’s most reliable warning signs — the more of it you have, and the faster it accumulates, the higher your risk of heart attack. For years, a tantalizing idea has circulated in both clinics and biohacker forums: that vitamin K2, a cheap over-the-counter supplement, might put the brakes on this process. The biology is plausible. Vitamin K activates a protein called matrix Gla protein (MGP), the body’s main built-in inhibitor of soft-tissue calcification. Without enough vitamin K, MGP stays inactive and calcium deposits go unchecked.
Until now, the evidence was a patchwork of trials in kidney-disease and diabetes patients, often muddled by co-administered vitamins and inconsistent results. A team at Maastricht University Medical Center set out to run a cleaner test. They recruited 180 patients with symptomatic coronary disease and moderate existing calcification, randomly assigning them to either MK-7 or an identical placebo for two years, with CT scans at baseline, one year, and two years.
The result: calcium scores climbed in both groups — this is a progressive disease and nobody expected reversal — but climbed measurably slower in the MK-7 group. Placebo patients went from a median score of 145 to 214 Agatston units; MK-7 patients went from 135 to 184. Calcium mass, a more reproducible metric, told the same story. Blood tests confirmed the supplement worked biochemically, with the inactive-MGP marker rising less in treated patients.
Here is the catch, and the authors are admirably blunt about it. The overall effect was modest. The proportion of patients who qualified as “fast progressors” — arguably the more clinically meaningful cut — did not differ between groups. And the trial measured calcium on a scan, not heart attacks, strokes, or deaths. There is even a wrinkle worth remembering: more calcium can sometimes mean more stable plaque, so slowing calcification is not automatically good. The honest verdict is that MK-7 does something real to a surrogate marker, at trivial cost and with no safety signal — but whether that translates into fewer cardiac events remains genuinely unknown.
Actionable Insights
Intervention: MK-7 (menaquinone-7), 360 μg once daily, oral, for 2 years, in adults with existing moderate coronary calcification (CAC 50–400 AU).
Effect size, made concrete:
Think of “calcium score” as a number that tracks how much hardened calcium has built up in the heart’s arteries. A higher number means more buildup, and the score naturally climbs over time as the disease progresses. The question is whether the supplement slowed that climb.
- Calcium score: Over two years, the placebo group’s score rose by 69 points — a 48% jump from where they started. The MK-7 group rose by only 49 points, a 36% jump. In other words, the supplement spared about 20 points of buildup, roughly a 29% smaller increase than placebo. The statistical models that accounted for other factors put the difference at about 22 points, and were confident the true effect falls somewhere between 13 and 31.
- Calcium mass: Measured a second way (the actual weight of calcium deposits), the placebo group gained 12 mg and the MK-7 group gained 7 mg — about a 40% smaller gain. The catch: once the analysis adjusted for other variables, the gap shrank to just 2 mg, so the real-world difference here is small.
- The “fast progressors” — the number that matters most: Beyond the average, the more meaningful question is how many people had their disease advance rapidly. Here the supplement made essentially no difference: 65% of the placebo group were fast progressors versus 58% on MK-7, a gap small enough that it could easily be chance (and the statistics confirmed it wasn’t a reliable difference). So while MK-7 nudged the group average in the right direction, it didn’t meaningfully reduce the share of people whose arteries were getting worse quickly — arguably the outcome you’d most want to change.
Take-home: For someone with documented coronary calcification, MK-7 is inexpensive, well-tolerated, and biologically active on a validated surrogate. It is not demonstrated to prevent events. The signal that efficacy may depend on actual vitamin K deficiency (treated patients’ dp-ucMGP still rose) suggests baseline status — not blanket supplementation — likely determines who benefits.
Source:
- Paywalled Paper: Two Years of Menaquinone-7 Supplementation and Coronary Artery Calcification
- Institution: Maastricht University Medical Center + CARIM (Cardiovascular Research Institute Maastricht), with VieCuri MC (Venlo) as the community-hospital site.
- Country: The Netherlands.
- Journal: JAMA Cardiology.
- Impact Evaluation: The impact score of this journal is 14.1 (2025 Journal Impact Factor; 5-year IF 15.6; CiteScore 32.7), evaluated against a typical high-end range of 0–60+ for top general science, therefore this is a High impact journal. (Within its own field, cardiac & cardiovascular systems, it sits at roughly the 97th percentile — effectively elite for a specialty title.)
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