Vitamin K2 half-life
Vitamin K2 is a fat-soluble vitamin, and its half-life in the blood depends heavily on which form is taken. The MK-7 form clears slowly, with a plasma half-life of roughly 3 days (about 68 hours in humans), so it stays in circulation between doses and gradually accumulates with once-daily use. The MK-4 form clears within hours and does not build up the same way, which is why it is usually taken in much larger and more frequent doses.
What a half-life actually means
A half-life is the time it takes for half of what is in your blood to be gone. It does not mean the compound is finished at that point. Half goes, then half of what is left goes, and so on.
That is why the last traces take so much longer to disappear than the first. Most references treat something as effectively cleared after about five half-lives, which for Vitamin K2 is roughly 2.1 weeks.
How Vitamin K2 clears
| Half-lives | Time since dose | Roughly left |
|---|---|---|
| 1 | 3 days | 50% |
| 2 | 6 days | 25% |
| 3 | 9 days | 12.5% |
| 4 | 12 days | 6.25% |
| 5 | 2.1 weeks | 3.125% |
These are round numbers from a single half-life figure. Real clearance shifts with dose, body composition, liver and kidney function, and what else you are taking. Treat it as a shape, not a schedule.
Why the timing matters
A short half-life means levels swing between doses, so timing and frequency do most of the work. A long half-life means levels build for days or weeks before they settle, so a change you make today might not show up for a while, and stopping does not clear things straight away.
Vitamin K2 sits at about 3 days, so it behaves like the medium end of that range.
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On a repeating schedule the amount in your body climbs until what you take in each interval matches what clears in it. That plateau is called steady state, and it arrives after roughly five half-lives whatever the dose. For Vitamin K2 that is about 2.1 weeks of consistent dosing.
The typical starting schedule is 1x daily with fat, at 100 mcg/day. Until that plateau, every dose lands on top of more of the last one than it will later, which is why the first weeks of a protocol can feel different from the same dose a month in.
Skipping doses resets part of that climb. One missed dose costs roughly one half-life of accumulation, so the shorter the half-life the more a gap matters.
Mixing and measuring Vitamin K2
Oral capsule — no reconstitution
Store at 15-25°C (room temp). 2 years sealed.