For most of a decade, vitamin D came with a warning: take it on its own, and the calcium it raises ends up in your arteries instead of your bones. The fix, supposedly, is vitamin K2. The claim is unusually specific for supplement advice, specific enough to put to randomized, placebo-controlled trials with arterial calcium scored on CT before and after. The trials came back. They don't agree with each other. So what does the evidence actually show, and did a 2026 trial change the answer?

0:00 – The trio everyone's told to take together

1:09 – The magnesium story

2:47 – Why K2 is different

3:45 – Putting it to the test

4:15 – What the trials found

5:55 – What you should actually do

6:40 – K2: cutting through the hype

7:06 – When it makes sense, when it doesn't