Vitamin K2 Dosage: How Much MK-7 to Take (and with Vitamin D)
Informational summary of published research — not medical advice. ⚠️ If you take warfarin, do NOT start, stop, or change vitamin K2 without your doctor managing it.
Quick answer
For the usual MK-7 form, take 90–200 mcg/day (the landmark trials used 180 mcg), once daily with a fatty meal. It's commonly paired with vitamin D (~100 mcg K2 alongside your D3). Note the MK-4 form is dosed in milligrams — ~250× higher. ⚠️ The critical rule: K2 opposes warfarin — never combine without a doctor.
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MK-7 vs MK-4: the doses are wildly different
The single biggest dosing mistake is treating the two forms as interchangeable. MK-7 works at micrograms (90–200 mcg) because it's well absorbed and has a long half-life, so it builds up in the blood (Schurgers 2007). MK-4 is cleared fast and barely detectable in blood at supplement amounts, so its research doses are in milligrams — up to 45 mg/day (the prescription osteoporosis dose in Japan), roughly 250× an MK-7 dose (Shiraki 2000; Sato 2012). Most everyday supplements use MK-7. For the full comparison, see MK-7 vs MK-4.
Find your vitamin K2 dose
Pick your reason for the MK-7 dose used in the trials and an honest read on the evidence.
We read the shelf: the dose is right, the form is the problem
Original research · we read 892 vitamin K2 labels filed with the NIH (of 4,426 on the market), and this reports the 327 sold as a K2 product. The other 551 are multivitamins, D3+K2 combos and bone-health blends where K2 is one line among many — a different product, and pooling them fails validation outright (the in-range figure swings from 47% to 15% depending which half of the read you look at, entirely on their account). Every percentage below was recomputed in both halves before being printed.
First, the good news, because it is not what we usually find. On most supplements we have measured this way the market sells well past what was studied, or well short. The K2 shelf does neither: the median product is 100 mcg, 75.8% clear the 90 mcg studied floor, and 63.6% land inside the 90–200 mcg range the trials used. If you buy a K2 product more or less at random, the dose is very likely to be defensible.
The problem is that the number alone does not tell you what you are holding. As the section above explains, MK-7 and MK-4 are both sold as “vitamin K2” and their studied doses differ by roughly 250×. So 100 mcg is a textbook MK-7 dose and about a 450th of an MK-4 dose — the same figure, two completely different meanings. 72.5% of the standalone shelf names MK-7 and 22.3% names neither form, leaving a milligram figure that cannot be mapped to any trial.
MK-4 products are rare on this shelf — we found 14 of them, which is enough to show a pattern and not enough to quote a share. Their median dose is 350 mcg. The MK-4 research dose is 45 mg — 45,000 mcg. Those products are being sold at a small fraction of the only dose their own form was ever studied at.
So the check is one word, not one number. Find MK-7 or menaquinone-7 on the panel and the milligram figure means what this page says it means. If the label says only “vitamin K2”, you are holding a number you cannot interpret, and if it says MK-4 at a microgram dose you are holding a form that has only ever been studied in milligrams. Every pick on this page names MK-7 for exactly that reason.
And to be straight about our own shelf: the wider vitamin K category we maintain does list one MK-4 product at 100 mcg. By the argument above that is not the one to buy if what you want is the K2 evidence — it is here because it is a real product people search for, not because we would recommend it at that dose.
Pairing K2 with vitamin D
K2 is often stacked with vitamin D3, and the logic is sound: vitamin D raises calcium absorption, while vitamin K2 activates the proteins (matrix Gla protein, osteocalcin) that steer that calcium into bone and away from arteries. A typical pairing is 100–200 mcg MK-7 with your D3, and combined softgels make it easy. Honest caveat: the mechanism and biomarker data support the combo, but hard outcomes are mixed — a 3-year trial of MK-7 added to D3 + calcium improved carboxylation markers but didn't change bone density (Rønn 2021). It's a reasonable, low-risk stack — not a guaranteed outcome.
By goal (what the trials used)
- Bone density: MK-7 180 mcg/day for 3 years slowed bone loss at the spine and femoral neck (but not total hip) in postmenopausal women (Knapen 2013); the MK-4 osteoporosis data uses 45 mg (Shiraki 2000).
- Arterial stiffness: MK-7 180 mcg/day for 3 years improved arterial stiffness (most clearly in women with stiffer arteries at baseline) and halved a vitamin-K-status marker (dp-ucMGP) (Knapen 2015). Higher dietary K2 intake tracked lower heart-disease risk in the observational Rotterdam Study (Geleijnse 2004).
- Honest limit: these are biomarkers and associations — no large trial has shown MK-7 supplements reduce actual heart attacks or strokes. One older open-label MK-4 trial (45 mg/day; Shiraki 2000) did report fewer fractures, but it wasn't blinded and used a ~250× higher dose — so it doesn't establish that MK-7 (the form most people take) prevents fractures. Promising, not proven.
MK-7 picks
100 mcg MK-7, 240 servings — the standard form at the lowest cost per day.
Vitamin D3 + 100 mcg MK-7 in one softgel — the convenient way to pair them.
300 mcg MK-7 if you want the upper end of the range; take with a fatty meal.
Compare all picks on the best vitamin K2 ranking, or see MK-7 vs MK-4.
Frequently asked questions
How much vitamin K2 should I take per day?
For MK-7 (the usual form), 90–200 mcg/day once daily with a fatty meal — the landmark trials used 180 mcg. MK-4 is different: research doses are 1,500 mcg up to 45 mg, ~250× higher. Not with warfarin unless your doctor manages it.
How much K2 with vitamin D?
Usually 100–200 mcg MK-7 alongside your D3 (combined softgels are common). Sound mechanism, but hard-outcome evidence is mixed — one trial improved markers without changing bone density. A reasonable low-risk stack, not a guarantee.
MK-7 vs MK-4 dose difference?
Large — MK-7 works at 90–200 mcg (long half-life, accumulates); MK-4 is cleared fast, so its studied doses are in milligrams (up to 45 mg), ~250× higher. 180 mcg MK-7 ≠ 180 mcg MK-4. Most supplements are MK-7.
Can I take K2 with warfarin?
Not on your own — the key safety rule. K2 opposes warfarin and can make it fail; even one typical MK-7 capsule can matter, and starting/stopping swings INR. Only with your prescribing doctor managing it. (Doesn't apply to apixaban/rivaroxaban — confirm with your doctor.)
Does K2 prevent heart disease?
Promising, not proven. MK-7 improved arterial stiffness and a K-status marker in a trial, and dietary K2 tracked lower heart disease in observational data — but those are surrogates/associations. No large trial shows K2 supplements cut actual heart attacks or strokes.
Related
- Vitamin K2: what the evidence shows
- MK-7 vs MK-4 — the forms compared
- Best Vitamin K2 Supplement
- Vitamin D Dosage Guide — the common partner
Sources
- Knapen MHJ, et al. "Three-year low-dose menaquinone-7 supplementation and bone loss." Osteoporos Int. 2013. PMID: 23525894
- Knapen MHJ, et al. "Menaquinone-7 improves arterial stiffness." Thromb Haemost. 2015. PMID: 25694037
- Geleijnse JM, et al. "Dietary menaquinone and coronary heart disease (Rotterdam Study)." J Nutr. 2004. PMID: 15514282
- Shiraki M, et al. "Vitamin K2 (menatetrenone) prevents fractures in osteoporosis." J Bone Miner Res. 2000. PMID: 10750566
- Schurgers LJ, et al. "Vitamin K1 vs natto-derived menaquinone-7; anticoagulant interference." Blood. 2007. PMID: 17158229
- Sato T, et al. "MK-4 vs MK-7 bioavailability in healthy women." Nutr J. 2012. PMID: 23140417
- Rønn SH, et al. "MK-7 on bone mineral density and microarchitecture (3-yr RCT)." Osteoporos Int. 2021. PMID: 33030563
- Couris R, et al. "Dietary vitamin K variability affects INR." Int J Vitam Nutr Res. 2006. PMID: 16941417